Two reviews:
Aim-1 & Sol-20
The Nascom
Story
Computing history
in school
Going on-line
with Pet
shoosing your
first computer-
eight-page guide
-Simplicity is the watchword
EUROC is anew, simple to use, fast, powerful
micro-computer system for business. It's British, the
programme tried and tested.
EUROC is already being talked about by bankers,
accountants and businessmen. See it on Stands 1 & 2 at
the Micro Computer show - Bloomsbury Centre,
July 5th to 7th.
EUROC hardware is manufactured exclusively for
Euro-Calc Ltd., by Plessey Micro Systems Ltd. EUROC
will be on permanent display at Euro-Calc’s branches at
55, High Holborn, London, W.C.1., and at 224, Tottenham
Court Road, London, W1.
For further information and trade-distribution enquiries, talk to Peter Ingoldby, Managing Director, Euro-Calc Ltd,
55, High Holborn, London, WC.1, telephone 01-405.3223 or Anthony Manton, Sales Director at y |
Tottenham Court Road on 01-636 5560.
@ Circle No. 101
actical
omputing
Managing Editor
Dennis Jarrett
Editor
Peter Laurie
Features Editor
Robert Walczy
Computabits Editor
Nick Hampshire
Staff Writer
Kay Floyd
Production Editor
Harold Mayes
Advertisement Manager
Erica Gibson
Advertisement
Department
Tom Moloney
Tina Roberts
Subscription Manager
Annabel Hunt
Publisher
Wim Hoeksma
Company-Secretary
Carole Fancourt
Managing Director
Richard Hease
Editorial: 01-359 8451
Advertising: 01-359 8151
Production and
Subscriptions: 01-359 7481
Practical Computing is
published by ECC as a
subsidiary of
WHICH COMPUTER? Ltd
at its registered office,
30-31 Islington Green,
London N1
and printed by
Eden Fisher Ltd,
Southend-on-Sea.
Distributed to newsagents
by Moore Harness Ltd.,
31 Corsica Street, London N5
and to specialist shops
by Practical Computing Ltd.
Subscription rates:
Single copy: 50p.
Subscriptions: U.K.,
£6 per annum
(including postage);
overseas: £12
(including airmail postage).
© Practical Computing 1979
ISSN 0141-5433.
Every effort has been made to
ensure accuracy of articles
and program listing. Practical
Computing cannot, however,
accept any responsibility
whatsoever for any errors.
PRACTICAL COMPUTING July 1979
CONTENTS
MICROCOMPUTER SHOW GUIDE
The official stand-by-stand guide to what can be seen and heard at the Microcomputer Show, July 5-7 . . 63:
REVIEW I- AIM-65
Full review of another microprocessor which has just been introduced to the market ............ ..38
REVIEW II- SOL-20
Full review of this microprocessor which just been introduced to the market............. ates = 2
GOING ON-LINE WITH PET
The first of two articles on how to get even more from your Pet .... 0.220600 eee 99
THE NASCOM STORY
We look at the leading British manufacturer which has just introduced the Nascom-2 ...............- 76
TEACHING HISTORY WITH A COMPUTER
The winner of the Research Machines computer in our Christmas competition shows how computers can
Delisediinnovativelylinischool! jcc... tS iwegeGen cc we FF ts ee a ee ee es Se 80
CHOOSING YOUR FIRST COMPUTER
Eight pages of advice on what to look for when making the great decision ....................-.,.-. §3
DESIGNING A SMALL BUSINESS APPLICATION
Partitwo oloumennee-partisenes . 222... .- ch qs ee inc fer Te, Se EB EIN EE FIG ee es aA
BIORHYTHMS - COMPLETE PROGRAM
Now you can use your computer to forecast your good and bad days by charting cycles ............. 103
LOW-COST WORD PROCESSING
We complete our two-part review on word processing systems available on micros . Berne aL
MICROCOMPUTER BUYERS’ GUIDE
Our invaluable guide to the microcomputers available on the market ............ we ; . 125
GLOSSARY OF COMPUTER TERMS
Our popular series explaining what the words mean .....-..... 222-00 eee ee 131
ALL THIS AND MORE
FREDBACK@ er ere -f.--e5 -- 6. ee: 33 APPRE Ri Bc sccm .cn .cx cere RESET he 97
Your letters and our replies More to do with your Apple
PRINTOUT Myee ing os oe. on » tie. ee. ae 36 MICRO MEDITATIONS ................ 107
All the news and the views Nick Laurence formulates an idea
CASSETTE SOFTWARE REVIEW ........ 84 DEAR rose om «ss ga en = Sey oT 109
Our views on ready-to-run programs Key future events
ILLUSTRATING BASIC ................. 87 C0 ee eee Se eee me O3
Teach yourself programming, continued We look at Rostronics
BOOKGRE VIEWS Wii oo. ine oneness 93 COMPUTABIUS yee som |. rae. See os 5 1313
All about what to read More articles for computer enthusiasts
TANDY. FORUM?) 0 ft 2 nee ee 95 ADVERTISEMENT INDEX .............. 133
Tips and ideas for the TRS-80
AUGUST ISSUE ON SALE JULY 11- ORDER NOW
Q
S
S
i
A
ib
mber one
micro-computer centre
If you’re wondering if a micro-computer
can help you, we are here to advise you.
At Lion House-London’s leading centre
for micro-computers-you'll find:
+ Experts who'll explain the equipment
in a way you can easily understand,
showing how and where it applies to your
work.
+ Demonstration areas where youcanget
immediate experience of using micro-
computers yourself.
»* Probably the biggest range of soft-
ware inthe UK.
+ Programmes can be tailored for your
particular commercial needs by our In-
House Analysts and Programmers.
+ Total service -including the availability
of full maintenance after you've bought an
installation.
> Leasing and HP. facilities immediately
available.
> A computer book section with publica-
tions that give you new insight into the
world of micro-computers.
AAR AAAAARAA?
& EKER
Telex: 28394 LionG.
Open 9 to 6, Monday to Saturday (Thursday to 7).
How will micro-computers help you? In
thousands of ways-only a few can be
mentioned here... pe)
MICRO-COMPUTERS
FOR BUSINESS
For business and professional, the
versatility of compact micro-computers
means that all the benefits of big com-
puters are made available to all atlow cost.
The businessman can now computerise
his accountancy, his stock control, his
records and much more -cutting his over-
heads and improving his efficiency.
For the home, micro-computers have in-
numerable uses and considerable value
too-sometimes in unexpected ways.
LION MICRO-COMPUTERS
SMALL COMPUTERS-TO MAKE YOUR BUSINESS BIGGER
Lion Computer Shops Ltd, Lion House, 227 Tottenham Court Road,
London W1 (First Floor). Telephone: 01-637 1601.
onweme
a OD)
ESS
=
MICRO-COMPUTERS
FOR THE HOME
Budgeting ... investments . . . con-
trolling heating or security ... storing
information on things like recipes...
designing complex and _ fascinating
games...education...
Come and see. We invite you to visit us
and investigate the possibilities and the
potential. If you're too far away, phone or
write and we'llsend youmoreinformation.
You need a micro-computer. We can
supply it.
@ Circle No. 102
PRACTICAL COMPUTING July 1979
GRAMA (WINTER) LTD
This is how your business appears on the screen
A complete Business Program Package free with the purchase of a 32-40K computer system. At
stand 46 Microprocessor Show only.
Approx 60 entries * updates require only 1-2 hours weekly and your entire business is under
control.
* PROGRAMS ARE INTEGRATED SELECT FUNCTION BY NUMBER
1=ENTER NEW NAMES/ADDRESSES 13=PRINT CUSTOMER STATEMENTS
2=* ENTER/PRINT INVOICES 14=PRINT SUPPLIER STATEMENTS
3=* ENTER PURCHASES 15=PRINT AGENTS STATEMENTS
4=* ENTER A/C RECEIVABLES 16=PRINT VAT STATEMENTS
5=ENTER A/C PAYABLES 17=PRINT WEEK/MONTH SALES
6=ENTER/UPDATE STOCKS REC’D 18=PRINT WEEK/MONTH PURCHASES
7=ENTER ORDERS REC’D 19=PRINT YEAR AUDIT '
8= EXAMINE/UPDATE BANK BALANCE 20=PRINT PROFIT/LOSS ACCOUNT
9=EXAMINE SALES LEDGER 21=UPDATE ENDMONTH FILES
10=EXAMINE PURCHASE LEDGER 22=PRINT CASHFLOW ANALYSIS
11=EXAMINE ORDER BOOK 23=ENTER PAYROLL
12=EXAMINE PRODUCT SALES 24=RETURN TO BASIC
WHICH ONE (ENTER 1 TO 24)
EACH PROGRAM GOES IN DEPTH TO FURTHER EXPRESS YOUR REQUIREMENTS.
FOR EXAMPLE (9) ALLOWS: z.. list all sales; b. monitor sales by stock code; c. invoice search; d. amend
ledger files; e. total all sales.
THINK OF THE POSSIBILITIES, AND ADD TO THOSE HERE IF YOU WISH
Note programs 19, 20, 22, 23 not linked at time ©! go'ng to press; estimated completion July. Price for current package £275 plus VAT, improved version — inc
aged debtors analysis etc. £375, or full listing pls nanual to be typed-in on most computer systems £150. Barclaycard enquiries welcome.
sp je systems tailored to your requirarm-ents {SWTP and PET) from £600 to £5,000 approx. Above package is intended to work with processor, twin-floppy
and printer.
LIS: OF FUNCTIONS AND FILES IN THIS PACKAGE
Program 1 BUS dis alay , above options
Program 2 TRANSAC1 cre .:es invoice file containing all sales information
Program 3 TRANSAC2 cre: ©3 accounts received file
Program 4 TRANSAC3 prin» sales invoices and credits
Program 5 TRANSAC4 ente s invoice details to monthly ledger
Program 6 TRANSACS ente:3 invoice details to 2nd ledger for payment
Program 7 TRANSACE links current invoice files to old file for third copy purposes
Program 8 TRANSAC7 updates payment ledger with monies received and rejects discrepancies
Program 9 TRANSACS8 prints final total outstanding and enters to liquidity
_ Program 10 PURCHAC1 enters purchases made and creates ledger file
Program 11 PURCHAC2 enters monies to be paid out, with a check against discrepancies
Program 12 PURCHAC3 updates purchase ledger file with new entries
Program 13 PURCHAC4 evaluates old creditors balances and updates to include purchases
Program 14 PURCHACS updates creditors balance to include payments made out
Program 15 PURCHACE evaluates and prints new ledger balances and gives final liquidity balance
Program 16 ADDRESS examines, adds, amends, prints lists of address files (up to 999)
Program 17 STOCK examines, adds, amends, prints lists, gives valuations of stocks on hand
Program 18 ORDER examines, adds, amends, prints lists, valuations and confirmations to clients
Program 19 TRANSPRT examines, adds, amends, prints lists of ledger entries and stocks sold
Program 20 PURCHPRT examines, adds, amends, prints lists of ledger files
Program 21 VATPRT lists ledgerfiles for three months and prints vatform entries
Program 22 CUSTPRT _ prints customer statements with aged debtor analysis for 1 or all clients
Program 23 AGENTPRT prints agent statements for 1 or all, with 4 commission rates presented
Program 24 SUPPRT prints suppliers statements
Program 25 ENDMTH _ updates all files for month end, to clear files to another disc
Program 26 BANK examines, adds, amends, totals bank transactions
Program 27 AUDIT (in work) prints years audit
Program 28 PROFIT (in work) prints years profit/loss account
Program 29 CASHFLOW (in work) prints years calendar of cashflow to include standing orders etc
Program 30 PAYROLL (in work) evaluatés weekly payroll and taxation applied to record files
FINAL 4 OPTIONS WILL ADD APPROX. £200 TO ABOVE
Please telephone for appointment — Tony Winter on 01-636 8210
GRAMA (WINTER) LTD 22 dncersantes. w.,
@ Circle No. 103
PRACTICAL COMPUTING July 1979
5,
BN
9999999999999999999Y
Sumlock Electronic
Services (Mi/cr) Ltd.
Manchester
Announcing the opening of our new showrooms
at 198 Deansgate.
is
#88 COMMODORE BASIC 888
31743 BYTES FREE
READY.
al
PAM is a self-contained add-on memory unit for PET computers. It is
available in 8K, 16K,-24K and 32K versions. 8K cards are available. to
augmentall but 32K versions ata later date.
Your North-West stockist of
Adler—Brinlock-—Busicom—Casio—
Commodore—Cannon—Sharp calculators.
Operation is simply by plugging-in to PET’s memory expansion port,
using the high-quality, protected connector provided, and to the mains.
PET power consumption, temperature and warranty are unaffected.
The standard, 24K version upgrades PET’s memory to the full 32K address-
able in BASIC, giving over 4 times the capacity of the standard 8K PET.
All units are guaranteed for 6 months and are supplied with full instructions
PRICES—8K £154
(ex VAT) 16K £232 plus £4.50 carr.
24K £310 and insurance
32K £367
8K plug-in card £78 plus £2.50 carr. and insurance
Over-the-counter repairs to all makes of
equipment
Commodore PET main agents
Prices are correct at time of going to press—subject to change without Prog rams written to customer specifications
notice,
OMB electronics, Riverside, Eynsford, Kent DA4 0AE
Tel: Farningham ee) 863567 Royal London House
99999999999999999999999999
pares sets asi ssistssistsistscstssistatsisicis
PET 196-198 Deansgate
_ MANCHESTER
M3 3WE
Tel: Sales/Software 061-834 4233
- @ Tel: Service 061-834 4234
Sehaas : DOLHOHOOOOHOGOOHHLHEL
@ Circle No. 104 @ Circle No. 105
New Low Price Miarsnalls
a ees ee or
Microprocessors
and associated
components
We distribute the fabulous KIM System - the ready
to use microprocessor system — a new concept in
microcomputers. Not a kit but supplied fully tested,
wired and guaranteed. Expandable memory that grows
with your system — not just an evaluation kit. Starting with
KIM 1 at £108.00 VAT incl. you get immediate capability
which can be expanded to a complete system capable of
: addressing up to 65K bytes of memory.
We also stock PET and a comprehensive range of ROMS, RAMS, PROMS, EPROMS, 74LS series, 74C
series, microprocessor support components, the National SC/MP Microprocessor and the MEK 6800 DI! kit.
In addition to these we stock an extensive range of discrete semiconductors, passive components and
DIL switches, etc.
Send for details to: MARSHALL'S ELECTRONICS Kingsgate House, Kingsgate Place, London NW6 4TA Tel: 01-624 0805
Retail Sales London: 40 Cricklewood Broadway, NW2 3ET. Tel: 01-452 0161/2. Telex: 21492
London: 325 Edgware Road, W2. Tel: 01-723 4242. Glasgow: 85 West Regent Street. G2 20D.
Tel: 041-332 4133. Bristol: 1 Straits Parade, Fishponds Road, BS16 2LX. Tel: 0272 654201.
NEW 1979 CATALOGUE NOW AVAILABLE 50p post paid or 40p to callers.
@ Circle No. 106
6 PRACTICAL COMPUTING July 1979
Room PC
313 Kingston Road, Ilford,
TE\tereases oe
A COMPREHENSIVE SELECTION OF MICROCOMPUTER BOOKS AND MAGAZINES
FOR THE HOBBYIST, EDUCATIONALIST, PROFESSIONAL AND RETAILER.
Introduction to Microcomputers: Microprocessor Interfacing Techniques £8.75
Vol 0: Beginners Book £5.95] Z80 Microcomputer Handbook £7.50
Vol 1: Basic Concepts £6.301 TV Typewriter Cookbook £7.50
Vol 2: Some Real Microprocessors (without binder) £18.95} T.T.L. Cookbook £7.50
Vol 2: Some Real Microprocessors (with binder) £24.70} CMOS Cookbook £7.95
Vol 3: Some Real Support Devices (without binder) £11.95] IC OP-AMP Cookbook £9.50
Vol 3: Some Real Support Devices (with binder) £17.70) RTL Cookbook £4.25)
Updating subscription (6 issues) for Vol 2 £18.95] IC Timer Cookbook £7.50
Updating subscription (6 issues) for Vol 3 £18.95] The Cheap Video Cookbook £4.30
Updating subscriptions for Vol 2 & 3 £30.00
1 Updating issue (specify for Vo! 2 or 3) £4.00} Introduction to Personal and Business Computing £4.95
1 Binder (Specify for Vol 2 or 3) £5.75] Getting Involved with your Own Computer £4.75
Your Home Computer £5.95
How to Profit from Your Personat Computer £6.50
6800 Programming for Logic Design £6.30
8080 Programming for Logic Design £6.30] Hobby Computers are Here £3.95
Z80 Programming for Logic Design £6.30] New Hobby Computers £3.95
Understanding Microcomputers and Smail Computer Systems £6.50
BASIC Computer Games £5.50) instant BASIC i
What To Do After You Hit Return £8.95] Basic BASIC £6.50
8080 Galaxy Game £6.95] Advanced BASIC £6.00
My Computer Likes Me... When| Speak in BASIC £2.75
Computer Rage (A Board Game) £6.95] Introduction to PASCAL £3.95
Artist and Computer £3.95
Accounts Payable and Accounts Receivable £10.95
Games, Tricks and Puzzles for a Hand Calculator £2.49} Payroll with Cost Accounting. £10.95
General Ledger £10.95
Z80 Instruction Handbook £2.95] Basic Software Library:
8080 Programmers Pocket Guide £1.95] Vol 1: Business and Games Programs £17.50
8080 Hex Code Card £1.95] Vol 2: Maths, Engineering and Statistical Programs £17.50
8080 Octal Code Card £1.95} Vol 3: Advanced Business Programs £26.95
: Vol 4: General Purpose Programs £7.95
Vol 5: Experimenters Programs £7.95
Dr Dobbs Journal Vol 1 £10.00] Vol 6: Miniature Business System £32.50
Best of BYTE Vol 7: Chess/Medbil/Wdproc Programs £26.95
Scelbi BYTE Primer £9.95
Best of Creative Computing Vol 1 £6.95 | Some Common BASIC Programs f £6.30
Best of Creative Computing Vol 2 £6.95] Computer Programs that Work (in BASIC) £2.55
Best of MICRO-6502 Journal £5.50 | First Book Of KIM £7.00
8080 Standard Monitor P
8080A/8085 Assembly Language Programming £6.45 | 8080 Standard Editor £9.95
6800 Assembly Language Programming £6.45 | 8080 Standard Assembler £9.95
8080 Software Gourmet Guide and Cookbook £6.95 | Special Package: 8080 Assembler, Editor, Monitor £20.00
6800 Software Gourmet Guide and Cookbook £6.95 | Bar Code Loader for 6800, 8080, Z80 and 6502 £1.75
Tiny Assembler for 6800 Systems £5.75
UK Overseas
Price Price Magazine Back Issues:
Subscriptions start within 3 weeks Micro-6502 Journal: £1.50
MICRO-6502 Journal (12 issues) £14.50 £15.00 Personal Computing £1.75
Personal Computing (12 issues) £16.00 £17.00 Interface Age £2.25
Interface Age (12 issues) £20.00 £21.00 |ROM £1,75
Dr Dobbs Journal (10 issues) £13.00 £13.50 |.Or Dobbs Journal £1.75
Computer Music Journal (4 issues) £10.50 £11.00 Computer Music Journal £3.75
Recreational Computing (6 issues) £8.00 £8.50 People’s Computers (recent issues called Recreational Computing) £1.75
BYTE (12 issues) £21.00 £21.00 | BYTE £2.25
Creative Computing (12 issues) £16.00 £16.50 Creative Computing £1.75
Calculators and Computers £1.75
Kilobaud (12 issues) £20.00 £21.00 puowaud (reprints only) es
3 .25
Microprocessors from Chips to Systems £7.95 | Magazine Storage Box (Holds 12) £1.25
THIS LIST CANCELS ALL PREVIOUS PRICE LISTS: EFFECTIVE APRIL 1979
DUE TO FLUCTUATIONS OF THE DOLLAR, PRICES SUBJECT TO CHANGE WITHOUT NOTICE
HOW TO ORDER Send to address above All Orders must be Prepaid |
Please note our prices include | Indicate Payment Method:
postage and packing, but not insur-
Magazine Subscriptions:
Total Enclosed £......... |
ance, if wanted add 12p for every | ain My cheque, P.O., I.M.O. is enclosed in Sterling on U.K. Bank
£10 of books ordered. Make che- : |
ques, PO’setc. payable to ess Charge to Barclaycard/Visa/Access/Diners/American Express
re BITC erbs abcented Credit CardiiNo ressaranscramenencesnersermeny. eroages Ss a ee a ee eo EX Piri Date iaccesscws. «genes |
BARCLAYCARD VISA/ACCESS | RII Satna eect a e
DINERS CLUB/AMERICAN EXPRESS ys ie |
N.B. Diners Club orders cannot be ING OSS kecowsers criqysevsvtssscnvevensucveses ss dvvcires 5 sgu5s ice encs sap tree COR Meee SEL LALO OTERO STN SRE Oe os
accepted by telephone. |
Phone: 01-553 1001 for Credit Card
orders (24-hr answering service) SIG PACUIMC, eerste acta tage cect scr ans ceop sense cere Be: reac retest Onmeenewrersciccs iiss cece rer Ras cas esau ving sens “|
All publications are published in U.S.A. and shipped air-freight by L.P. Enterprises. in unusual cases, processing may exceed 30 days.
Prices subject to change without notice.
TRADE ENQUIRIES WELCOME
@ Circle No. 107
PRACTICAL COMPUTING July 1979 zy,
THERE’S MORE TO LUTON THAN
CAMPARI AND THE AIRPORT
There’s the Commodore PET, the APPLE II, the North Star Horizon, Processor Technology’s
Sol, Cromemco’s Z2, Z2D and System 3. Together with disc drives and terminals and printers
and VDUs and all manner of accessories and books and magazines. Almost everything the
Personal Computer lover could wish for. So put away the holiday brochures and come
along to —
Ssierdwoods
PERSONAL COMPUTER SYSTEMS
110 Leagrave Road - Luton - Tel (0582) 424851 - Just off the M1.
With acknowledgements to David Campari and Luton Airport
@ Circle No. 108
ALMARC PRESENTS:
MORE FROM VECTOR GRAPHIC
Now Vector Graphic give you more for your money with
the 48K dynamic ram board and the System B
Wale VECTOR «GRAPHIC MZ THE VECTOR GRAPHIC ers em GB
*" AMHZ Z80A CPU *-Complete Vector MZ system plus:-
" 48K ram “Vector Mindless terminal
* 630K Bytes disk storage * Flashwriter 2 video board (24 x 80)
* Serial port and two parallel ports * Software driver on prom
* Prom/ram Board with monitor *" MZOS North Star compatible DOS
“ MDOS Operating system * CP/M configured by Almarc
* Z80 Assembler
* Basic Interpreter
Price £2300-00 plus VAT Price £2850-00 plus VAT
Plus a large range of CP/M compatible software including Fortran, Cobol, Macro
assemblers etc.
Contact: ALMARC DATA SYSTEMS LTD.
29 Chesterfield Drive, Burton Joyce, Nottingham.
Telephone 0602 248565
@ Circle No. 109
8 PRACTICALCOMPUTING July 1979
The microcomputer for those who
need more than the minimum. The
right processor for business,
scientific and educational use.
Proven applications include Games
e Educational e Word Processing «
Invoicinge Stock Control
e Sales Ledger e
Purchase Ledger e
Mailing e Scientific.
Languages
Powerful Basic including sequential
and random access disc files e
formatted output e strings e line
editor e machine languageCALLe
many other facilities. Optional
additional software
(under CP/M
operating system)
includes BASIC
compiler, FORTRAN and COBOL.
Horizon Z80A computer with 2 double~density
disc drives and 24K RAM £1,823 (exclusive of
VAT and carriage).
The Horizon computer
includes:-
Specification
Zilog Z80A MPU e S-100 bus (12 slots}e Solid
well-built case e Up to four Shugart mini-floppy
disc drives. I80KB each e Serial port for CRT or =.
Teletype e Real-time clock on motherboarde 44@&%
\ Optional additional
serial port and
parallel port e
Powerful operating
system and monitor
¢ Access to wide
range of S-100
special application
boards.
Equinox Computer
Systems Ltd.
“Kleeman House”
16 Anning Street,
New Inn Yard,
London EC2A 3HB.
Tel:01-739 2387/9,
01-729 4460.
For North Star Horizon systems and software
contact the people ‘with experience:
LONDON
Equinox Computer Systems Ltd.,
16 Anning Street, New Inn Yard,
London. EC2A 3HB.
(Tet: 01-739 2387/9-01-729 4460)
HUNTS
Paxton Computers, 26 High Street,
Great Paxton, Huntingdon, Cambs.
PE19 4RF. (Tel: 0480-213785).
HANTS
Claisse-Allen Computing, 5 Upper
High Street, Winchester.
(Tel: 0962-69368).
LANCS & NORTH WALES
Cortex Computer Centre, 25/35 Edge
Lane, Liverpool. (Tei: 051 -263 5783).
KENT
SCOTLAND
Scotia Software Services,
95 Woodfield Avenue, Edinburgh.
(Tel: 031-441 603).
SURREY
Radix 2 Technology 1.14...
92 Wimbledon Hill Road, Wimbledon,
S,.W.19. (Tel: 01-946-8887).
DORSET
Biue Chip Microsystems, Market
Place, Sturminster, Newton, Dorset.
DT10 1BB. (Tel: 0258-72946).
CAMBS
Wisbech Computer Services Ltd.,
10 Market Street, Wisbech, Cambs.
(Tel: 0945-64146).
Microtek Computer Services, 50 Chislehurst Road, Orpington,
Kent, (Tel: 66-26803).
Tor Business Systems, 83 Timberbank, Vigo Village, Meopham,
Kent, (Tel: 0732-822956).
ESSEX
DEVON
J.A.D, Integrated Services
(Plymouth) Ltd.
21 Market Avenue, City Centre,
Plymouth, Devon.
(Tel: 0752-62616).
MIDDX
Jacobs Computer Systems Ltd.,
36 Bengeworth Road, Harrow, Middx.
HA1 3SE. (Tel: 01-908-1134),
SOUTH WALES
Micro Media Systems, 12 Clarence
Place, Newport, Gwent.
(Tel: 0633-50528),
LINCS
Loveden Computer Services,
167 Bartowby High Road, Grantham,
Lincs. (Tel: 0476-72000).
UINOX
COMPUTER SYSTEMS LTD.
“Kleeman House” 16 Anning Street,
Micro Software Systems Ltd., Stanhope House, High Street,
New Inn Yard, London EC2A 3HB.
Tel: 01-739 23879. 01729 4460.
Stanford-le-Hope. (Tel: 03756-41991/2).
@ Circle No. 110
PRACTICAL COMPUTING July 1979 9
Your Own Complete
PERSONAL MICRO COMPUTER
for only £305:00 war 24 extra 8%)
THESE ARE THE FEATURES
Standard Keyboard (ASCIi Encoded)
Ready Built 12” VDU Monitor (uncased)
Complete Kit of Parts to construct a: powerful
Microcomputer
Full Documentation
On Board PROM Programmer
Tiny Basic Interpreter
Programmable in Machine Code or Basic
Powerful Motorola Software Available
Additional options available as standard without
obsoleting any previous purchases
Such as: More Memory both ROM and RAM, Hard
Copy Printer, Floppy Dics, I/O User Ports and Software
for the above, i.e. Disc Operating System and Disc
Interactive Extended Basic.
ORDER NOW!! We take plastic or real money!!
CROFTON
Electronics Limited
35 Grosvenor Road, Twickenham
Middlesex e Tel: 01-891 1923
@ Circle No. 111
NORTH STAR COMPATIBLE SOFTWARE
ALLEN ASHLEY ENTERPRISES is
PDS Program Development System for 8080 or Z80 computers PDS is an exceptionally 75.00
powerful assembiy language development package. PDS includes a unified assembler/
editor, a macro assembler with a relocating linking loader, a string oriented text editor
and trace debugger/disassembler, POS supports full 280 code. The following is a list of 75.00
source modules compatible with PDS:
MODULE FUNCTION REQUIREMENTS
ALPHSORT High speed alphabetic sort None 10.00
NUMRSORT High speed numeric sort None 10.00
FPPACK BCD floating polnt arithmetic None 10.00
FOURIER Fast Fourier transform FPPACK 10.00
MINV Matrix Inversion FPPACK 10.00
MATPRO Matrix Product FPPACK 7.50
RATPOL Rational function and utilities FPPACK 7.50
SORT Square root FPPACK 5.00
TRIGS Sine, cosine, TAN, ATAN FPPACK, RATPOL 10.00
LOGEXP Exponential, logarithm FPPACK, RATPOL 10.00
FPIOP Floating point 0 None 10.00
FORMAT Formatted floating polm output None 7.50
NFILES North Star disk handler None 10.00
INOPS. integer multiply/divide None 5.00
The complete set of modules (Iistad above) 59.00
THE BYTE SHOP OF WESTMINSTER
NORTHSHARE North Star BASIC timesharing package. Supports two to four terminals
Each terminal shares the same copy of BASIC simultaneously; but independent of the
other user(s}. All book-keeping is done by a separate task supervisor. 37.00
DIGITAL RESEARCH
CP/M Disk Operating System. Includes an 8080 assembler, general purpose text editor
and an advanced debugger with HORIZON customisation. 90.00
DESPOOL - Permits simuttaneous printing of date from disk while user executes
another program from the console. 45.00
MAC — Macro Assembler, features include an assembly-time expressions, conditional
assembly, page formatting and a powerful macro assembler. 85.00
SID - Symbolic Instructlon Debugger 60.00
TEX = Text formatter. 60.00
INFORMATION UNUMITED
WHATSIT - Data Base Management System. Supports a disk-resident data base and
processes enquiries (as well as updates} in a real-time conversational mode. 55.00
MICRO MIKES
4/SSHARE — Interrupt Driven Bank Switching Timesharing Software for the North Star
HORIZON computer. Timesharing executive resides in the first 8X of RAM. 37.00
MICROSOFT
FORTRAN-80 — ANSI ‘66 {except for COMPLEX), plus many extensions. Includes
relocatable object compiler, linking loader, library with manager, Z80 assembler and
cross reference utilities. 245.00
Disk Extended BASIC — New version, ANSI compatible with long variable names,
WHILE/WEND, chaining and much more.
ORGANIC SOFTWARE
TEXTWRITER I! — Affords word procassing capability for North Star systems under the
CP/M Operating System. 59.00
INTERAM Computer Systems Ltd.,
59 Moreton Street, Victoria, London SW1V 2NY
01-834 0261/2733
SUPERBOARD II
4K — £263", 8K — £299°
(Modulator included)
FIBRE GLASS CASE £24.95
TRS -80 KEYBOARD
4K LEVEL Il - £390°, 16K -£490°
(Modulator included)
POWER SUPPLY £9.90"
ATARI VIDEO
COMPUTER
VCS — £139", CARTRIDGES £12.95°
NEW - CODE BREAKER, BRAIN GAMES
HUNT & SCORE
SOFTY EPROM
DEVELOPMENT
BURNER SYSTEM
(Kit) - £79.50"
“PRICES EXCLUDE 8% VAT — FULL DETAILS ON REQUEST
VIDEOTIME PRODUCTS
56 Queens Rd, Basingstoke
Hants RG21 1REJ
Tel: (0256) 56417. Telex: 858747
@ Circle No. 112
NORTH STAR COMPATIBLE SOFTWARE
NORTH STAR
PASCAL Development System = Includes an editor, compiler, debugger and file
handier {requires 48K RAM). 37.00
PAS-AUX — Auxillary package for the above. Inciudes an assembler and utilities. 27.00
NSSE DISKS 1-12 - North Star Software Exchange volumes one to twelve. Each disk
generally contains # specific set of programs; whether games, mathematical routines,
PILOT System, ulilhties or various applications software.
Each volume (disk) is priced at 6.00
The complete set of twelve disks is priced at 43.00
Special versions of North Star BASIC (please supply serial no. of your present copy).
That is either 10, 12 or 14 DIGIT PRECISION BASIC. 15.00
SYRUCTURED SYSTEMS
CBASIC-2 = Commercial BASIC Pseudo Compiler. 65.00
All the above software is normally supplied on North Star compatible media. Please specity when
ordering whether software is for a North Star single (Releases 1, 2, 3 and 4) or dua! (Release 5)
density system. Comming soon ... Accounting software, ie. Inventory, General Ledger, Payroll
etc. Software products are being continually added to our range so please enquire about software
not listed here.
NORTH STAR HARDWARE
€ Kt £ Ass.
HORIZON-0-0K 475.00 650.00
HORIZON-1-16K-D 995.00 1265.00
HORIZON-2-16K-D 1245.00 1575.00
HORIZON-1-32K-D 1125.00 1445.00
HORIZON-2-32K-D 1375.00 1785.00
Z80A Processor Card 145.00 175.00
Hardware Floating Point Board 195.00 215.00
16K RAM Board 225.00 275.00
32K RAM Board with Parity 375.00 425.00
HRAZ-SIO Serial Port 29.00 45.00
HRZ-PIO Parallel Port 23.00 45.00
North Star compatible disk (1-99) 3.00
North Star compatible disk {100-999) 2.25
North Star compatible disk (1000+) 2.00
Library Case for above {holds ten disks) 2.00
OTHER MANUFACTURERS
Cromemco TU-ART 1/0 card 130.00 180.00
Heuristics 20S speech card n/a 145.00
Heuristics 50S speech card n/a 225.00
Morrow B080A CPU/Front Panel n/a 195.00
Parasitic Engineering Equibox n/a 495.00
Parasitic Engineering Euinox 100 n/a 625.00
Amp S-100 (IMSAI type} edge connector 3.25
Elbit DS1920, mode! 30 VOU n/a 700.00
All caps mod. for above n/a 10.00
Page/Scroll software switch mod. n/a 25.00
Interdec Intertube I} VDU n/a 525.00
All pices given are exclusive of VAT and carriage, and are corract at time of going to press
Educational and OEM terms are available on request. Piaase send 12p stamp for full details.
INTERAM
Circle No. 113
10 PRACTICAL COMPUTING July 1979
0.K. SO you've got a computer.
So we've got all the add-ons!
Floppy Disks
Micropolis drives are available in 143K and 31 5K (formatted) versions expandable from One to four drives in
various packaging options. Prices quoted below are for single 143K units including 240V power supply and
case. f
For $100 computers: Cromemco, Vector, Horizon, SOL, Sourcerer with $100 expansion.
4042-1 Master unit; includes controller card and Micropolis system software £499 1022-1 Add-on unit £339
cp/M £100 COBOL £400
For NASCOM and other small Z80 configurations:
44382 Master unit; includes controller card and Raindos system firmware €499 1022-1 Add-on unit £339
For Motorola D1/D2, SWTPC MP-68 and other small 6800 configurations:
443BM Master unit; includes controller card and RPDOS system firmware £499 1022-1 Add-onunit £339
For TANDY TRS 80 with expansion interface:
4027 (T) Drive 1, 2,30r4 £339
For $100 computers: For $$50 (SWTPC, MSI) computers:
vector 8K Static £150 4K Static €¢ 80
Vector 16K Static with bank switching £300 8K Static £140
Vector 48K Dynamic, 280 refresh £500 32K Dynamic, Onboardrefresh €495
Microspeech
For SS5S0 (SWTPC, MSI) computers:
Microspeech analogue speech synthesiser converts text strings in phonetic spelling to audio output.
Complete with special BASIC interpreter €295
6
All prices exclude VAT and carriage Si ntrom
Dealer enquiries welcome
ee for complete shortform Mi | > ros h O 2
Please enquire for add-ons to computers et eaves Ce ems
not mentioned above ' :
SINTROM GROUP = Telephone Reading (0734) 85464
@ Circle No. 114
PRACTICAL COMPUTING July 1979 1
BUILD THE
NASCOM 1 W British Design W UK Best Selling Kits
COMPUTER rurt arter sates seavice & GUARANTEE
We ara the Sole Approved London Stockist and National Distributor
FREE MODULATOR and 8-BUG
FEATURES €165 - 8% VAT
We Supplied in kit form for POST FREE
self-assembly
W Full documentation supplied
% Fully screened double-sided
plated through hole printed circuit
board
W Full 48 key keyboard included
%& 2K x 8 Ram
Ww 1K x 8 monitor program in.
Eprim
tw Powerful Mostek Z80 CPU
% 16 x 48 character display
interface to std un-modifled T.V.
W T.V. display memory mapped
for high speed access additional 16 1/0 lines
Ww On bosrd expansion to 2K we Memory may be expanded to
x 8 Eprom A full 60K
12,000 ALREADY SOLD
KITS IN STOCKS .
DP-1000
Series Printers
Ww On board expansion for
EXPANSION
YW Expansion buffer board £32.50
MEMORY KITS (inclusive all
hardware)
8
¥ 1/0 board with decoders and
all hardware except ICS will
accept up to 3 PIOs, 1 CTV and
OTHER HARDWARE
%& 3A power supply tor up to
32K expansion £19.90
wIA power supply for up to "
32K expansion Mk It... ...£24.50
Ww 8A power supply for larger
than 32K expansion .....€60.00
wW Expansion card frame ..£29.60
we E PROM programmer . £40. 00
%& E PROM Eraser
Ww Keyboard cabinet
¥% Programming manual ..
SOFTWARE
wk 1K x-8 monitor program
providing
W 8 operating commands,
supporting Mem examine/modify,
tabulate, copy, break, single step
execute tape, load, tape dump
W Reflective monitor addressing
for flexible monitor expansion
through user programs
W Monitor sub-routines include—
delay ASCII coding, binary to hex
convers/pn, clr screen, scroll up;
string print, cursor shift and many
others
NEW T-4 operating system in (2)
2708 EPROMS upwards
compatible from T2 and B-BUG
Tiny Basic
Super Tiny Basic (with editor
and machine utility routined} £35.00
Zeap assemble? editor . £32.00
Prints 40 cps in 40 columns.
Plain paper, multiple copy.
Data storage — 168 characters. A
Ww VAT 8% ALL ITEMS EXCEPT BOOKS ye DEMONSTRATIONS CON-
TINUOUS DAILY © ye WE WELCOME EXPORT--EDUCATIONAL AND
§tNDUSTRIAL ENQUIRIES yw FREE BROCHURE—SEND SAE 93 x 63
STAMP 12}p.
Current Loop, RS.232
Parallel Bit inputs. Anadex Lta.
Dorna House, Guildford Road,
Phone: Chobham (09905) 6333
Telex: 858762 ANADEX G
@ Circle No. 117
London W2
All mail to: Double width printing selection. West End, Woking, Surrey
ES ENRGS Henry's Radio _——_ GU24 9PW
404 Edgware Rd
Phone (01) ny 1008
OEM quantity price £295
@ Circle No. 115
PERIPHERALS
“Pet Peripherals
Internal memory expansion 24K £320
(full instructions included)
External memory expansion
(available from 8K to 32K) from £169
8K Plug in cards for above £85
Anadex DP-8000 printer
(including |/EEE interface for Pet) £679
Pet 2001 8K £550
Pet 2nd cassette deck £55
Kim-1 available ex-stock £99-95
COMPUTER SYSTEMS LTD.
Introducing our new keyboard, which boasts 71 profes-
sional reed switches, & a full upper/lower-case ASCII
Output, switchable to Teletype/Telex mode.
Please send for further details.
REMEMBER! Do you need a ee keyboard, or a cheap
one?!
BASIC KIT PRICE £92.50 + VAT.
Basic Kit + numeric pad £99.50 + VAT.
Special offer to purchasers of 1648 VDU & Keyboard —
£212 + VAT, the pair, save £10.
ALSO NEW A complete stand-alone monitor less terminal
housed in steel-variants available for OEMS — Please write
or ‘Phone for details.
1648 VDUs still available in built & Kit versions.
£154.50 & £129.50 + VAT.
We also stock a comprehensive range of software
for Commodore Pet.
Send for our comprehensive hardware and soft-
ware Catalogue.
Add 8% VAT to allitems.
Computer Division
D.A.M.S. (Office Equipment) Ltd.,
30/36 Dale Street,
Liverpool L2 5SF
TANGERINE COMPUTER SYSTEMS
LTD.
Rivermill Lodge, London Rd., St. Ives,
Huntingdon, Cambs. PE17 4BR.
| TEL: (0480) 65666. _
@ Circle No. 116
@ Circle No. 118
12 PRACTICAL COMPUTING July 1979
CHIC
SGlENTIFIC
Microcomputers from the world’s largest
PUY Se Seo CoLrer
Mini Floppy
ini
20K RAM oP
Basic + Assembler
Personal, Games, Small
Business & Educational Disks
90K Mini Floppy Storage
Printer Interface
OS 65D V:30 Operating System
International Distributors:
American Data-Home and
Office Computer,
1030—15th Street, N.W., Suite 300,
Washington, D.C., 20005
Tel: (202) 466-6612
Telex 64405
See your nearest auth-
orised dealer for full
price list and
catalogue, of
Challenger IJ, I I,
series.
pa Littleborough Lancs ane Lit ice Giese
acu uarry Hill, Box Corsham
Conia a a nil Sota Wiltshire SN14 HT
London W‘ Tel: 01-580 8841 Components
14 Station Road Thames Personal
The Byte Shop Ltd New BarnetHertsENS1QW Computers
426-428 Cranbrook Road, Tel: 01-441 2922 13 Wilmot Way Camberley
Gants Hill, Ilford, Essex Surrey Tel: 0276-27860
: Linn Products
Tel: 01-518 1414 235 Drakemire Drive U Microcomputers
Castlemilk Glasgow PO Box 24 Northwich
brook
Tochiical Seevs0es G45 952 Scotland Cheshire CW8 1RS
1 Higher Calderbrook Tel: 041-634 3860 Tel: 0606-75627
@ Circle No. 119
PRACTICALCOMPUTING July 1979 13
FOR NASCOM-1%
IN SCOTLAND “
COME TO
STRATHAND aay, * aT
VT monitor & Keyboard Kits
9
2
a
°o
oy
Available now
ex-stock
we ew
WewLR
HA =5*
— +
In stock; Nascom-1 buffer boards 8, 16,
32K RAM boards. Super Tiny Basic zeap on Keyboard Monitor
tape. *Full 128 character ASCII *Resolution — 80 charo/line
encoding *Video response — 20 MHz
*+5 volt only *All inputs TTL compatible
*Positive or negative strobe *9" diagnonal high resolution
*Circuit, layout and full tube, P4 (white) phosphor
assembly instructions *625 or 525 line standard
*Two-key roll over *+11v @ 1A input
*Price £28-50 0 50p p/p *Price £85 + £2 p/p
GLASGOW (041) 552 6731
Telephone order welcome with Access
and Barclaycard.
Coming soon — boxed, built and tested VDU full
cursor control, 16 x 64 format, keyboard & display
included — price £280.
All prices include VAT — discounts available
BOOKS AND SOFTWARE Please note it is
ee won ra tees not our policy to Vid T a i
AND COLLEGES NOW advertise Nascom
AVAILABLE. products which t €0 ermina )
are not currently 197 Hornbeams, Harlow, Essex
available.
Tel 0279 30132
@ Circle No. 120 @ Circle No. 121
PCC 2000 PCC 2000 PCC 2000
Low-Cost Business Computer
Hardworking
Easy to use
Designed for the Smaller Business
Nationwide Field Servicing
Business Packages available
Word Processing
{BM Compatible
Built and backed by the Pertec Computer
Corporation
SOFTWARE
CP/M. BASIC. FORTRAN. COBOL.
FEATURES
64K Bytes RAM: 4 Channel DMA:
Vectored Interrupt Handling:
1.2 Megabytes Disk Storage:
Built-in CRT with forms handling.
Meconmpelce
14-15 BERNERS STREET, LONDON WP SDE
Telephone 01-636 1392
Circle No. 122
14 PRACTICAL COMPUTING July 1979
comart
... the specialists
Ali the small computers you Contact us and discover how
need! your application can benefit
Micro computers for scientific from cost-effective micro-
research, control, educational computing.
A Cromemco System 3/64
Computer
B The North Star Horizon
C Processor Technology's SOL
and commercial applications.
Comart have single card
computers for control;
development systems and
interface boards for research;
multi-user systems for
education and word processing
for commercial users.
The computer systems are
modular and flexible — you
choose only those facilities
you need.
PRACTICAL COMPUTING July 1979
Contact us direct or call your nearest Comart dealer
The Byte Shop, liford, Essex. Tel: 01-554 2177
Cambridge Computer Store, Cambridge. Tel: (0223) 68155
Microcomputermart Ltd., Manchester. Tel: 061-832 2269
Crayworth Ltd., Camberley, Surrey. Tel: (0776) 34044
Digitus Ltd., London W.1. Tel: 01-636 0105
Holdene Ltd., Leeds. Tel: (0532) 459459
isher-Woods Ltd., Luton, Beds. Tel: (0582) 424851
Newbear Computing Store, Newbury, Berks. (0635) 30505
Xitan Systems Ltd., Southampton. Tel: (0703) 38740
@ Circle No. 123
15
NASCOM
FLOATING POINT
BASIC LEVEL C Runs on an 8K system
Full floating point arithmetic
Software compatible with Levels A and B
Contains all features found on A and B Plus more
Line editor, 52 variables
Commands include:—- FOR; NEXT; READ; DATA; PEEK;
ANNOUNCING A FANTASTIC
NEW LOW COST PRINTER
= THE TRENDCOM 100 40 COLUMN HIGH PERFORMANCE :
SERIAL PRINTER WITH:-
POKE; IN; OUT; USR; INKEY . rif ake ction |
a. 3 cter Set including lower cas oe
BASIC LEVEL A Runs on the minimum Nascom se ae a 2 q ae 33
NO extra memory needed 33 %& = Bi-Directional Look-ahead Printing ss
Fitted in 2 minutes in place of monitor a8 ‘ P a
Integer arithmetic <,>, <>, <=, >=,= es ae Rmaniting 3
Fast execution time 7: % Low cost White Thermal! ss
Keyboard pause and interrupt AH Paper with Blue or Black Print 4
Abbreviated commands allow economical use of your!|# y Attractive Casing 4
memory, and consist of:— LET; PRINT; IF; GOSUB;
RETURN; INPUT; REM; STOP; GOTO; LIST; NEW; RUN;
SAVE; ABS; RND
BASIC LEVEL B As previously advertised. eleliiliibeiaeales sg =—
£295Ex VAT #
LEVEL A or B in 2x2708 PROMS £21.50 3 * Interface for Pet, Apple 11, TRS 80 or Sorcerer 3
LEVEL B Cassette £7.50] |=: * 1 80 ft. Roll of Paper (Blue Print) re
LEVEL C in 4x2708 PROMS £42.00 || #3 * Delivery UK Mainland
LEVEL C Cassette £12.50
a pie al £5.00 JUST PLUG IN AND START PRINTING!
uperstartrek for Level BorC £4.50 ;
Relocator package £4.00 dig bre ed
ADD 8% VAT.
All products fully documented
CCSOFT (Southfields)
83 Longfield St London SW18
Tel 01-870 4891 (Anytime)
Callers by appointment please
@ Circle No. 124
DETnSae
OF? DON 10
BUSINESS!
WYESIDE COMPUTING
NETHERTON
ROSS-ON-WYE,
HEREFORDSHIRE. Tel: (0989) 4321
@ Circle No. 126
KES (Computers)
make little things mean a lot
Consult KES (Computers) before you buy a
Microcomputer System or you could make an
expensive mistake.
KES (Computers) can give you expert and
independent advice to help you make a
profitable decision.
KES (Computers) can provide —
@ tailored system design of hardware and software
for your application.
@ Ideas (fully developed) of products for you to
ACCOUNTS RECEIVABLE!
ACCOUNTS PAYABLE,
INVENTORY, LEDGER,
WORD PROCESSING, produce and/or sell.
INFORMATION HANDLING, ;
WHATEVER. @ Complete microcomputer systems by OHIO
Ohio Scientific’s full lineup of small business computer systems
can handle any part of your business. Or all of it. Quickly,
accurately, and economically. Each model costs less at the start.
Nice for small budgets. And using a low-cost building-block ap-
SCIENTIFIC INC. costing from £200 to £12,000
based on 6502, 6800 or Z80.
proach, Ohio Scientific’s computers can grow with your needs.
Simply, you get the most for your money, right from the start.
There’s a full library of easy-to-use business programs, too.
See this onlo SCIENTIAG dealer today’
MILLBANK COMPUTING
2, EAST LANE, KINGSTON UPON THAMES. SURREY
KT1 2NN ENGLAND TELEPHONE.O1 549 7262 TELEX.8951525
~~ @ Circle No. 125
Contact KES (Computers),
4 Summerfields,
Yarnfield,
Stone, Staffs.
ST15 ORH.
Telephone 0785 77 297
@ Circle No. 127
PRACTICAL COMPUTING July 1979
in about the same area as this advertisement, we
have designed a microcomputer with 20K of
addressable memory ON-BOARD. With Kansas
City standard cassette interface ON-BOARD. With
TV/monitor interface ON-BOARD. With control
decoding ON-BOARD. With all bus lines fully
buffered ON-BOARD.
We call this microcomputer Nascom-2. And for
under £300 this is what it has:
Microprocessor
Z80A. 8 bit CPU. This will run at 4 MHz but
is selectable between 1/2/4 MHz.
This CPU has now been generally accepted
as the most powerful, 8 bit processor on
the market.
The software library for the Z80, with its
base around the 8080, has rapidly
expanded with the increasing use of its
more powerful instruction set.
Hardware
12''x 8" Card
All bus lines are to the Nasbus
specification.
All bus lines are fully buffered.
PSU +12v, +5v, —12v, —5v.
Memory
On-board, addressable memory :—
2K Monitor — Nas-Sys | (2K ROM)
1K Video RAM (MK4118)
1K Work space/User RAM (MK4118)
8K Microsoft Basic {MK36000 ROM)
8K Static RAM/2708 EPROM
INTERFACE
Keyboard
New expanded 57 key Licon solid state
keyboard especially built for Nascom. Uses
standard Nascom, monitor controlled,
decoding.
TV.
The 1v peak to peak video signal candrivea
monitor directly and is also fed to the on-
board modulator to drive the domestic TV.
PRACTICALCOMPUTING July 1979
If you can buy more on one board
for under £300-
buy us one too!
2/4MHr
CRYSTAL Clees
OSCILLATOR
& DIVIDERS
rd
al:
a
{
NASCOM 2 in outline
1/0
On-board UART (Int.6402) which provides
serial handling for the on-board cassette
interface or the RS232/20mA teletype
interface.
The cassette interface is Kansas City
standard at either 300 or 1200 baud. This is
alink option on the NASCOM-2.
The RS232 and 20mA loop connector will
interface directly into any standard
teletype. .
The input and output sides of the UART are
independently switchable between any of
the options — i.e. itis possible to use
input on the cassette and output on the
printer.
PIO
There is also a totally uncommitted Parallel
1/0 (MK3881) giving 16, programmable,
I/O lines. These are addressable as 28 bit
ports with complete handshake controls:
On-board Decoding
The NASCONM-2 makes extensive use of
ROMS for on-board control decoding. This
reduces the chip count and allows easy
changes for specialised industrial use of
the board.
Link options are on-board to allow the
Reset control to be reassigned to an
address other than zero.
Character Generators
The 1K video RAM drives a 2K ROM
character generator providing the standard
ASCIl character set with some additions,
128 characters in all. There is also 4 socket
for an optional graphics ROM on-board.
The PCB is, of course, of industrial
standard, through hole plated, masked and
screen printed.
Documentation.
Full construction article is provided for those
who buy a kit and an extensive software
manual is provided for the monitor and
Basic,
We think no other board has quite so
much on it for £295 (plus 8% VAT).-If you
find a board that has more, buy one for
us too!
Nascom Microcomputers
121 High Street Berkhamsted Herts.
(04427) 74343
@ Circle No. 128
LINBURG ELECTRONICS LTD
QUALITY SEMICONDUCTORS WITH FULL
INDUSTRIAL SPECIFICATION
74LS TTL
74LS00 19p
74LS01 19p
74LS02 19p
74LS03 19p
74LS04 20p
OUR 1979 CATALOGUE RAM
2102A-2
1024 x 1 250ns
1.19
including the first edition of
STOP PRESS
* LATEST LOW PRICES
* FASCINATING NEW ITEMS
* SPECIAL OFFERS
a bargain on their own
* LOWEST PRICES EVER FOR TTL
MOTOROLA
MC6800P CPU £7.10
MC6810 RAM £3.20
MC6820 PIA £4.50
MC6850 ACIA £4.50
MC6875 CLOCK £3.80
1
16 For £16.96
18
Linburg
aD
D2EVALUATION KIT £176.00
(MEK 6800 D2)
ZILOG
280 CPU 2.5MHZ £14.00
Z80 CTC £9.00
Z80 PIO £9.00
PROMS
2708 1K x 8 EPROM £6.75
2716 2K x 8 EPROM £17.00
(TEXAS TRIPLE SUPPLY
VERSION)
SUPPORT CHIPS
MC1488 V24 Tx
MC1489 V24 Rx
8216 BUS DRIVER
AY-5-1013 UART
8 in. FLOPPY DISCS
(SINGLE DENSITY,
SINGLE SIDED)
74LS08 20p
74LS10 20p
74LS14 74p
74LS20 22p
74LS27 32p
74LS30 26p
74LS32 26p
74LS42 88p
74LS47 £1.00
74LS74 30p
74LS75 40p
74LS90 54p
74LS93 54p
74LS155 57p
74LS174 80p
74LS367 54p
PLEASE ADD 30p
POSTAGE AND PACKING
AND THEN ADD 8%
V.A.T.
LINBURG ELECTRONICS LTD
DEPT PC, MOSS WAY DONIBRISTLE
INDUSTRIAL ESTATE, HILLEND
DUNFERMLINE, SCOTLAND
TEL: (0383) 823222
@ Circle No. 129
* FREE 45p WORTH OF VOUCHERS
USE OUR "ORDER-RING” LINES RN
VAT INCLUSIVE PRICES P+ P 25p
CHROMASONIC
electronics
56 Fortis Green Road,
Muswell Hill London N10 3HN
Telephone 01-883 3705/2289
@ Circle No. 130
SMALL SYSTEMS ENGINEERING LTD.
(Incorporating R. BAILEY ASSOCIATES)
62 New Cavendish Street, London W1M 7LD, Tel: 01-637 0777, Telex: 8813085 Abacus
A MAJOR SUPPLIER OF PET MEMORY BOARDS AND
INTERFACES IN EUROPE
PET BOARDS
Sole official U.K. Agent for PME memory boards.
We provide approved technical back-up, up-grade and service
facilities for these boards in the U.K.
Internally mounting memory boards available in 2 configurations;
—24K .... £328 —32K .... £432
IEEE-488/RS232C SERIAL INTERFACE
—Fuil {EEE address decoding, RS232C or 20mA loop output,
—Switch selectable Baud Rate, Crystal controlied Baud Rate timing,
—Boxed units complete with connectors, full operating instructions
and sample programs supplied
—Lower Case Printing
—Serial Interface 8, input and output... . £186
—Serial Interface A, output only . . . . £106
IEEE-488/CENTRONICS TYPE PARALLEL INTERFACE
Low cost unit without IEEE address decoding
Also suitable for Anadex DP-8000 Printer. : . . £45
ANALOG INPUT/OUTPUT
—IEEE-488, 16 Channel, 8 Bit A-D .. . . Price to be announced
—lEEE-488, 16 Channel, 8 Bit D-A . . . . Price to be announced
CUSTOM INTERFACE DESIGN
Interfaces designed for special applications. Interfaces supplied so far
include Analogue Input/Output, XY plotter, stepper motor control.
PET INTELLIGENT TERMINAL SOFTWARE PACKAGE
A software package which, in conjunction with an Interface B
enables the PET to operate as an intelligent terminal. The software
implements full 1BM or DEC protocols .. . . £100
TV/VIDEO MONITOR INTERFACES
—Video and UHF output (piugs into aerial socket of domestic TV)
urea fso
IEEE-488 TELEX PUNCH AND INTERFACE
—50 chars/sec. Telex punch... . Price to be announced
NOW AVAILABLE
P & T 488 S-100 IEEE-488 INTERFACE
—Interfaces S-100 computers to the
IEEE-488 instrumentation bus.
—Functions as a 488 controller, talker
or listener.
—Three software packages available:
North Star DOS/BASIC interface
CP/M interface.
Custom systems interface package... . £325.
TERMS: All prices EX. VAT. All orders C.W.O.
Cheques should be made payable to SMALL
SYSTEMS ENGINEERING LTD. Orders should
include £2:50 P&P per unit. All goods supplied
under 90 days warranty.
@ Circle No. 131
PRACTICAL COMPUTING July 1979
Dik SINGLE BOARD
al bo COMPUTER
In the August issue of PE, we will be
presenting COMPUKIT UK 707. It
compares very favourably with
machines three times its price and is
similar to Superboard II (recently
reviewed by us) using the same 8K
Microsoft, full feature, BASIC which
runs faster than other currently available
personal computers. Faster than some
business computers. Its features are:
© Up to 8K RAM on board.
¢ Fully expandable via on board
sockets.
© Cassette interface (CUTS).
¢ VDU — with its own dedicated
RAM (1K).
¢ Full ASCII keyboard.
e U.H.F. modulator on board.
¢ P.S.U. on board, transformer
included in kit.
© Full machine code monitor (2K)
and 1/0 utilities in ROM.
© Upper and lower case plus
graphics and gaming characters.
It will mate with all Superboard extras.
For example:
© Expander board for up to 24K
static RAM.
© Mini-floppy interface.
® Port adaptor for printer and
modem.
¢ OSI 48 line expansion interface.
Compukit UK 107 will sweep the board in the hobby
computer field. It is an excellent design with full feature
(not Tiny) BASIC. A complete kit will be available from
Computer Components for £219+ VAT.
FULL CONSTRUCTIONAL DETAILS
STARTING IN
PRACTICAL
ELECTRONICS
AUGUST ISSUE ON SALE FRIDAY, 13 JULY
@ Circle No. 132
PRACTICAL COMPUTING July-1979 19
20
NEW DOLPHIN BD 80 PRINTER
om
Low cost 80 column printer combining simple mechani-
cal design with sophisticated micro-processor contro},
upper and lower case, 112 c.p.m., many features.
Stand, cables, memory buffers available.
E-stock prices from £595.
Dealer enquiries invited.
SPECIAL OFFERS for July only.
CP/M now available on Micropolis Mod II configured
for Sorcerer — £98.
C12 Computer Cassettes 42p each — £3.75 for 10.
5” diskettes — £29.50 per box of 10.
2708 EPROMS - £7.99 each.
NEW PRODUCT
DOLPHIN PRINTER is plug compatible to the Sorcerer's
serial and parallel interfaces and is supplied in a beige
cabinet — plug in and print.
The EXIDY MONITOR and PROGRAM DEVELOPMENT
ROM PACS are on demonstration in our showroom.
| SORCERER TECHNICAL Manuals and handbooks are
available ex-stock.
A vast amount of software is nearing completion, so
please keep in touch for early news of availability.
EXIDY SORCERER — A COMPLETE BUSINESS SYSTEM
UNDER £3000 + VAT 32K Machine with Z80 processor
and 8K ROM BASIC. 128 character ASC11 keyboard and
superb graphics.
DOUBLE DRIVE configured MICROPOLIS DISK SYSTEM
with MDOS or CP/M 630Kb. Professional quality
monitor, various sizes up to 16”. Printer — optional 80 or
132 column printer. Software packages are available or
can be written to your own specification.
The system can be expanded to suit your own
applications.
UNDER £1000 — BASIC SYSTEM
32K Machine, 10” professional monitor (not a converted
TV), quality cassette recorder, necessary cables, manu-
als etc.
| Price £999 + VAT.
Sorcerer Prices from £650 (8K).
|
77/68 BEARBAGS - The well supported 6800 based kit
from Newbear. Active user group.
PRINTERS — CENTRONICS, DOLPHIN, OK11.
MONITORS — Professional quality 9”, 10”, 12”, 16”
(ideal for teaching).
COMPUTER BOOKS — for professionals, hobbyists,
businessmen and newcomers. Catalogue now contain-
ing updates — over 500 titles — Micro, Mini and
Mainframe. Quantity discounts available.
CROMEMCO 2Z2 —- The powerful one — ASSEMBLER,
MACRO ASSEMBLER, FORTRAN, COBOL, DATA BASE
MANAGEMENT, WORD PROCESSOR.
Prices from £395 (Z80 Single Board Computer)
NORTH STAR HORIZON - The popular computer for the
business user. Expandable to 48K, 3 diskettes and
hardware floating point. Basic system 16K. RAM, serial
interface. EXTENDED BASIC, DOS, CP/M, mini diskette
and power supply.
Prices from £1295.
SOL 20 —- The professional terminal computer re-
nowned for its high quality capacitative keyboard and
Word Processing application. Minimum 16K RAM,
monitor, serial and parallel interfaces. EXTENDED
BASIC, FORTRAN, FOCAL, ASSEMBLER, EDITOR,
GAMES, mini floppy disks.
Prices from £1785.
SOL* STAR WORD PROCESSOR from £2500.
THE COMPLETE SERVICE
Feasibility studies — undertaken by our senior consul-
tant analysts with long experience of commercial data
processing.
Software packages available and/or specially designed
and written for your own applications.
We can supply work stations for your computer
hardware, standard configurations or made to mea-
sure. Insurance, maintenance, HP facilities BARCLAY-
CARD, TRUST-CARD, ACCESS.
Universities, Colleges and Schools — official orders
welcome.
OFFICES & SHOWROOM open Monday-Saturday 10.00a.m.-6.00p.m.
Personal callers welcome (Please phone first).
34B London Rd., Blackwater, Camberley, Surrey. Telephone (0276) 34044.
Telex 858893 |
@ Circle No. 133
PRACTICAL COMPUTING July 1979
TAKE A NEW LOOK AT
SC/MP
Our new SC/MP NIBLE-BASIC Mic-
rocomputer kit system is available.
This new National Semiconductor SC/MP-
based microprocessor is more versatile
than many similar systems. The CPU board
includes a pre-programmed 4K Nible-Basic
interpreter ROM in conjunction with the
SC/MP II. The board also incoyporates
RS232C/V24 input and output buffers.
Full kit price, including PCB and instruc-
tions £50.95.
SC/MP microprocessor board plus 4K
RAM board. Special Price £139.00
When used with our other kits you will
have a useful and reliable computing
system with plenty of scope for expansion.
To launch this new board we are offering a
special package deal on a complete system.
This package includes:
SC/MP Microcomputer Board (79075);
ASCII Keyboard (9965); 4K RAM (9885);
Power supply (9066); TV Display terminal
(9966); BUS Board (9857); TV Modulator
(9967) inclusive of VAT£275.00
Compare this to other systems available as
KITS. Remember that we sell only first-
class components and PCBs. We do not try
to cut corners by supplying inferior keys or
flimsy unmarked boards. Most of the
boards are standard Eurocard size for rack-
mounted systems. A cassette interface card
software will be
with built-in control
available shortly.
=. -
BUS PRINT | BUS PRINT
EPS 9857
BUS PAINT
MODULAR
MICROCOMPUTER
SYSTEM KITS
Semiconductor SC/MP microprocessor.
They offer a unique stage-by-stage building
and learning system which develops froma
simple digital display unit, through a HEX
address and display stage, to a complete
minicomputer with ASCII Keyboard and
TV display. The system is robustly con-
PRACTICAL COMPUTING July 1979
These kits are based on the National
structed, which makes it ideal for use in
Schools and Colleges where microcompu-
ter techniques are now part of the syllabus.
Many of the kits can be used to supplement
other systems.
SC/MP Board and RAM Input/Output
Board
These demonstrate the working of the SC/
MP chip. Data is fed in using digital
switches and read out on LEDs
9846-1/2 £26.75
CPU Board
This is used in conjuction with the RAM
board and contains all the devices needed
to control the overall system.
9851 £42.90
Memory Extension Board
This contains 3/4K of RAM and 3K of
PROM. It also houses the multiplexer and
the priority decoder. This enables the SC/
MP to handle interrupt requests from more
than one peripheral device.
9863 £38.50
BUS Board
Simple interconnection system for the
Eurocards
9857 £3.00
HEX input/output board
Used in place of the RAM input/output
board, this unit enables the SC/MP to be
addressed in hexadecimal. The board also
displays Hexadecimal output using seven-
segment LED displays.
9893 £62.55
ELBUG
Three pre-programmed EPROMS de-
signed to control the system.
9800E £37.00
Power Supply
Designed to power all the units in the
system with room to spare to power
additional boards. +5 Volts 3 Amps, -12
Volts 0.5 Amps.
9066 £19.50
4K RAM Card
Full 4096 x 8-bit RAM capacity. More)
than one of these cards can be added to the
system using a simple buffer circuit.
9885 £92.55
Cassette Interface
Record and replay your programs using
this Kansas City format interface. Transfer
Tate up to 1,200 baud.
9905 £16.50
ASCII Keyboard
Uses the AY-5-3276 encoder to provide all
the alphanumerics and control functions
for the microprocessor system. Full-size
keyboards.
9965 £46.50
@ Circle No. 134
TV Display Terminal board
Used in conjuction with a TV modulator,
this board enables a display format of 16
lines of 64 characters per page to be
displayed on a normal television set.
Cursor and scrolling functions are in-
cluded. The unit also offers a choice of six
baud rates.
9966 £69.00
TV Modulator
For use with the display board
9967 £6.45
Microprocessor Interface
Input/output buffer to interface RS232C
amd V24 type equipment with either KIM
or our SC/MP system.
79101 £6.75
Further details of this system on request.
TV GAMES COMPUTER
KIT
Most TV Games fall into one of two
catagories. Either their programs are fixed
by the type of control IC which generates a
few simple bali games, or they can be re-
programmed by plug-in modules. The
modules for the latter type tend to be
expensive and it is always uncertain just
how long the manufacturer will issue new
games.
This TY GAMES COMPUTER over-
comes these problems by enabling the
owner to take advantage of the software
available and to devise new games using
the keyboard. These programs are then
transferred to tape for future use. The
game is controlled by the Signetics 2650
Microprocessor IC and offers up to eight
colour variations in the display, together
with a score count system and sound
effects. The unit also includes joystick
control for two players.
_ Full data supplied with the kits.
Keyboard (79073-2) £26.10; Main Board
(79073) £166.40; Power Supply (79073-1)
£14.20; Modulator (9967) £6.45; Joystick
Controls £5.50 each
Special package price of all these kits plus
Software record. £215.00.
Individual components for all these pro-
jects are available, send SAE for prices.
All our prices include VAT rate applicable
at the present time. We reserve the right to
change our prices should this rate be
altered.
HOW TO ORDER
U.K. Orders:Send Cheque or Postal Order
payable to DE BOER ELEKTRONIKA,
2 Lynn Road, Grimston, Kings Lynn,
Norfolk, PE32 1AD. Add S0p for postage
and packing. Telephone Hillington (04856)
553. Office hours Mon-Fri 9.00am-5.00pm.
Overseas Orders: De Boer Elektronika,
Kleine Berg 41, Eindhoven, Netherlands.
Telephone 40-448229 Telex 59307.
Pdebocr
elektronika
Kleine Berg 38-41 Eindhoven, 4
Nederiand, 1e1, 040-448229
ee |
21
Which British system can offer the following:
COLOUR. Aerial Input, Alphanumerics
and Graphics
BBC Television Teletext
service
IBA Television Teletext
service
ROM-Resident
Interpreter
Motorola 6800 Machine
Code
Instant Information service
CEEFAX.
ORACLE.
BASIC.
MONITOR.
VIEWDATA.
TECS:
TECHNALOGICS
EXPANDABLE
COMPUTER SYSTEM.
Prices start at around
£360.
Rack-mounting and Tabletop versions
(illustrated) —The Logical Development everyone
has been waiting for.
See us onstand 11 at The Microcomputer Show.
Please send large S.A.E. for details to:
TECHNALOGICS (DEPT. PC)
8 Egerton Street, Liverpool L8 7LY
@ Circle No. 135
22
Mol MINE OF INFORMATION LTD Mol
1 FRANCIS AVENUE, ST ALBANS AL3 68L ENGLAND PHONE 072752801 TELEX 925859
SELECTED MICROCOMPUTER BOOKS
PASCAL
WILSON/ADDYMAN £3.50 A Practocal tntroduction to Pascal
1978 148pp Excellent vaiue for money
0 333 23582 7 Reprinting in May 1979: reserve your copy now!
HARTMANN AC 5.20 Concurrent Pascal Compiler for Minicomputers
1977 119pp Describes v seven pass compiler generating Virtual code for
0 387 082409 any 16-bit computer
JENSEN/WIRTH 5.20 Pascal User Manual & Report: 2nd Edition
1975 167pp Recognised as the international reference work on Pascal
0 387 90144 2
COLEMAN Derek 5.50 A Structured Programming Approach to Data
1978 222pp
0 333 219430
OGDIN Carol Anne 6.60 Software Design For Microcomputers
197B 196pp How to tackle the software crisis
013 8217440
BOWLES Kenneth 7.00 Microcomputer Problem Solving Using Pascal
1977 563pp This book teaches the extended Pascal from UCSD which 1s
0 387 90286 4 sweeping the micro community
GROGONO Pater ‘7.60 Programming In Pascal
197B 359pp Probably the best American book avattable for learning
0 201 02473 X Pascal
KIEBURTZ Richard 8.00 Structured Programming and Problem-Solving With Pascal
1978 365pp This book emphasises method mare than janguage
O 13 854869 2
HOW TO ORDER
Circle the price of each title chosen and indicate quantity required
f
Total value of books chosen
Extra one percent of value for insurance in transit
Extra £1 for delivery outside the UK {any quantity}
TOTAL DUE © Cheque 1 Bank draft
== © ACCESS {) PO/IMO
Make cheques etc Creditcard number:
Payable to ‘Mol’ Cardholder‘s signature:
Your reference:
Mol ref:
Name:
Address:
Please phone and complain if books do not arrive within 14 days
1 Please invoice
Prices are subject to change without natice, due to external factors
E\terprses >
RECENT ADDITIONS TO OUR RANGE
OF BOOKS
RA6800ML — An M6800 Relecatable Macro Assem-
bler by J. E. Hemenway
LINK 68 — An M6800 Linking Loader by Grappel
and Hemenway
Calculating With BASIC by R. Guido
Users’ Guide to North Star BASIC by R. R. Rogers
Programming the 6502 by R. Zaks -
SCELBAL High Level Language plus Supplements
by Arnold & Wadsworth
PIMMS ~ A Database Management System.
Program Design
MONDEB ~ An advanced M6800 Monitor Debugger
by D. Peters
SUPER-WUMPUS - A game in 6800 Assembler
code and BASIC, by J. Emmericks
HOW TO ORDER
Send cash with order to L. P.
Enterprises, Room NB/PC, 313
Kingston Rd, Ilford, Essex IG1
1PJ. Credit card orders (not
Diners Club) accepted by
telephone. Tel. no. 01-553 1001.
Payment must be in sterling and
drawn against a British bank.
Mol
1 FRANCIS AVENUE, ST ALBANS AL3 68L ENGLAND PHONE 072752801 TELEX 925959
ed. by Liffick
6800 Tracer — An aid to 6800 Program debugging
£5)
£15.95
£5.50
£4.95
£10.00
£7.95
£20.00
£5°95
£4.25
£3.50
£4.25
@ Circle No. 136
MINE OF INFORMATION LTD Mol
SELECTED MICROCOMPUTER BOOKS
Scientific American
1977 145pp
0 7167 0066 2
LIPPIATT Arthur
1978 192pp
0 13044750 1
OSBORNE Adam
1977 300pp
0 931988 08 x
OSBORNE Adam
1977 350pp
0931988 020
BARDEN William
1977 240pp
0 672 213516
ZAKS Rodnay
1977 420pp
0 89588 001 8
SARRON/CURNOW
1979 244pp
0903804 425
STOKES Adrian
1979 10Cpp
0 905897 218
ALCOCK Donald
1979 134pp
0521 217040
LE€/BEECH/LEE
197B 100pp
0905104 03 x
NEVISON John
1978 t5ipp
G@ 201 052474
LEWIS TG
1978 256pp
0 8104 5761 X
AHL David (ed)
1978 185pp
0 89480 052 3
BOSWORTH/NAGEL
1977 224pp
0574 21090 3
POOLE/BORCHERS
1978 193pp
0 931988 06 3
POOLE Lon
1978 375pp
0 931988 136
POOLE/BORCHERS
1979 375pp
0931988 209
£3.20
4.00
5.40
7.50
4.50
6.30
9.50
START HERE!
Microelectronics
Broad semi technical introduction
Architecture of Small Computer Systems
Clear and methodical British textbook
Volume Zero: The Beginner's Book
Gently leads the reader up to Valume One
Volume One: Basic Concepts
One of the wartd’s best selling textbooks enhanced by free
Mol list of pedantic corrections.
How to Buy and Use Mini and Micro-computers
C201 Microprocessors: Fram Chips to Systems
Very populer starter book for those with a background in
electronics
The Future With Microelectronics
This powerful new book will almost certainly form the basis
of UK Government policy this year
Viewdata: A Public Information Utility
BASIC
Hhastrating BASIC
Excellent book for novices explains haw to write portable
Programs in BASIC
Computer Programs That Work!
Twenty four educational programs oriented ta schoo! sclence
including the game of LIFE
The Little Book of BASIC Style, or How to write a program
you can read
With 19 rules and ten complete program examples
How To Profit Fram Your Personal Computer
Ideas on how to make it pay for itself
BASIC Computer Games - Volume 1
Latest revised editian using Microsolt Basic makes this
excellent value for money
Programming in BASIC For Business
Aims to get you writing useful programs quickly
Some Common BASIC Programs
Seventy six tested programs in finance, maths, statistics
Accounts Payable and Accounts Recelvable
Documented program tistings in WANG BASIC make @
complete business package
General Ledger
Documented program hstings in WANG BASIC for another
complete business package
@ Circle No. 137
PRACTICAL COMPUTING July 1979
DATA PRECISION [Equiament] Lid.
~-
DETAILED SPECIFICATION
MODEL VDP 10
VIDEO
— One page memory
*64 characters per line *16 lines per page
— Full 128 ASCII character set
*96 upper and lower case characters *32 control symbols
— Comprehensive cursor controls
*Left/right/up/down *CR/LF *Clear/home/line-erase
— PROM ttranslation from inbound characters, giving:-
*Proqrammable coding for cursor commands
*Programmabie display control for each input code
— Cursor command codes can be displayed using:-
“Display’ key for protocol debugging *V28 input bit 8
under remote software control
— European compatible composite video out for:-
*TV monitor, or *Modified TV set.
V28 1/0
— High/low rates externally switchable and jumper selectable
from:-
*9600/4800/2400/1 200/600/300/150/75 bits/sec
*220/110 bits/sec. (NOTE: at high receive speeds, remote
software should allow 8.3 ms for CR. LF and 132 ms
tor Clear)
*Odd, Even or No Parity *Full duplex or local mode
*One or two stop bits *V24 serial 1/O using standard 25 pin
socket
KEYBOARD
— 72 key ultra-reliable solid state contactless keyboard
— Standard ASCII layout plus programmable cursor control
keypad
— QWERTY standard, AZERTY optional extra
— Full N key rollover
— Caps Lock with LED for TTY compatibility
— Repeat key.
MAINS POWER SUPPLY
— Built-in — needs 220-240V 50Hz.
PRACTICAL COMPUTING July 1979
proudly present
THE
VIDEO
KETBOARRU
— 72 key ultra-reliable contactless capacitive keyboard
with cursor command keypad
— RS 232/V24 serial |/O up to 9600 bauds
— Composite video output for monitor or modified TV
— Built-in mains power supply
Although low-cost, the Video Keyboard is‘OEM built
in the UK using only top-quality components. Other
low-cost products use cheap, low MTBF contact-switch
keyboards. The Video Keyboard uses the same pro-
fessional quality ultra-reliable contactless keyboard
used by top-flight UK terminal manufacturers.
CABINET
— Tailor-made to house all electronics, keyboard, video and
V24 sockets, switches and power supply.
SWITCHES
— Power on/off
— On-line/Off-line
— Baud Rate Select
*Medium/High/Low “Normally set to 9600/1200/300
— Display Key
*Displays contro! characters for easy protoco! debugging
AVAILABLE IN TWO VERSIONS (Monitor/converted TV not
included). ;
Complete Video Keyboard. ..... £260+VAT (UK p&p paid)
Stripped Video Keyboard ....... £190+VAT (UK p&p paid)
[stripped version excludes case, case hardware (switches,
plugs), 240/9-0-9 VAC transformer but otherwise complete
and tested]
Both versions are brand-new with data sheets and 12-month
warranty.
DATA PRECISION (Equipment) LIMITED,
81 Goldsworth Road, Woking, Surrey GU21 1LJ
Tel: Woking 64444/67420 Reg. in England No. 913775
Please send me:
.... Complete Video Keyboards @ £280.80 each, inc. VAT
and UK postage and packing
«... Stripped Video Keyboards @ £205.20 each, inc. VAT
and UK postage and packing
[J | enctose my cheque
LC} Charge to my VISA/ACCESS/DINERS Card Not VISA
LILI tii ttt |
Name
Address
Signature
@ Circle No. 138
23
24
A bef - ¥ rs | q ;
Pweemorphic Etc.
a We Products
Wet stocks
mum K. Only
mgales over-
2 are Mounts to
trade Prices. - usm
For exampige:: Fey
Econorafi.
bytes staat y+
Econoratfigy, iy D
bytes st ney | -
Econbratee lt, SAP Z Zax
bytes WHRRY tara RES EZ S
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Ass.
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fi ne is
foe £195
£275
£359
Econora
bytes stax
All prices iitGi
(overseas ¢
Further 5%
Also Educditig
Please sent
@ Circle No. 139
SIRTON PRODUCTS (sP)
Micro Software Systems
DESK TC? COMPUTERS
A
A really affo: iat: 2 and reliable computing
system con pris! g acommercial
microcomp.!:er \ y:th dual disc drives, VDU
and printer, with accounting and payroll
software dutie: i !s now available to
businessmen f{ » just £4,500 exc. VAT.
Full details of ‘his and other systems
available.
EES
Micro Software Systems,
Stanhope House,
Stanford-le-Hope,
Essex
Tel: Stanford-le-Hope (03756) 41991/2
13 WARWICK ROAD
COULSDON
SURREY Tel: 01-660 5617
MIDAS $100 SYSTEMS
Substantial
stock.
MIDAS 1: Z80 System from £625 (built)
MIDAS 2: S80 Disc System from £1100 (built)
DON’T MISS THE
Mainframe to house your $100 system, with
optional 5” or 8” disc drives. Special systems built to your
requirements from Z80 CPU and other S100 boards held in
Don’t Bore your Computer with Data Preparation!
Let it run programs that work for you while the TEXTOR is used
to edit programs and data off line.
TEXTOR has 2K of user memory, text editing facilities, and
transmits and receives via serial link to your computer.
FROM £485
Mainframes from £228
SDS 200 BUSINESS COMPUTER
COMING JULY
JADE «© CROMEMCO + SDSYSTEMS >
ITHACA AUDIO «
GODBOUT + ECT + SSM « Etc
a
@ Circie No. 141
PRACTICAL COMPUTING July 1979
QTY.
DIODES/ZENERS
20-pin
22-pin
24-pin
28-pin
1N914 100v 10mA 0 LM323K 5.95 LM380_ (8-14 Pin}1.19
1N4005 600v 1A LM709 (8-14 Pin) .35
1N4007 1000v 1A
1N4148 75v 10mA
1N4733 5.1v 1 W Zener. 65 ECGNAIS 35
= . i)
1N753A 6.20, 500 mW Zener . LM309K (340K-5) 1.50 LM340T18 95
1N758A 10v ” LM310 85
1N759A 12v ” LM311D 715
1N5243 13v ” LM318 1.75 LM340K15 1.25
1N5244B8 14y Trae LM320H6 719 LM340K18 1.25
1N52458 15v a SMa 20H 5 79 LM340K24 1.25
: LM373 2.95
SOCKETS/BRIDGES LM320K12 Ee
8-pin LM320K24 1.65 78L12 Z
14-0 LM320T5 1.65 78L15 75
alii
16-pin
18-pin
LINEARS, REGULATORS, etc.
QTY. QTY.
7905 (LM320K5) 1.65 LM377 3.95
74221 74LS02
1.00
74367 74LS04
40-pin . ww 74.0535
Molex pins .01 To-3 Sockets 74LS08 35
2 Amp Bridge 100-prv 74809 35
25 Amp Bridge 200-prv 74LS10 35
= 74S11 35
2, TRANSISTORS, LEDS, etc. et 2
"_2N2222 _(2N2222 Plastic .10) 15 Aico ce
2N2222A “74183235
74.37 35
PNP (Plastic Unmarked) 4034 2.45 mae 45
NPN (Plastic Unmarked) 4035 75 ee 5
NPN 4037 1.80 74.842 75
NPN 15A 60v 4040 75 :
PNP Darlington 4041 “69 T4LS51_ 48
LED Green, Red, Clear, Yellow = 4.874 45
D.L.747 7 seg 5/8’' High com-anode 1,95 4042 65 MALS76 50
4043 50 ‘T4886 45
.65 74890 65
: 74893 65
MAN74 7seq com-cathode (Red) 1,50 “741810750
FND359 7 seg com-cathode (Red) 1.25 74L8123 1.20
74LS151 85
9000 SERIES i 741815385
Qty. QTY. 74H101— 74LS157 85
— a & 3322 ad 74H103 74LS160 95
f 3308 38 5 74106 —-aLS164 1.20
4069/74C04 35 B uss 1 BS
MICRO’S, RAMS, CPU’S, E-PROMS 7418244 1.0
enNE SUM: 741836795
8113 1.50 2107B-4 4.95 448367 95
BT23 ; 741$368 95
BT 24 74800 35
74802 35
8197
|—__3 z a 80325
[ 1488 1,25 2716 (5v) 4515 2.95 T4304 25
1489 1.25 2758 (5v) 4519 85 74505 35
1702A 4.50 3242 : 74808 35
AM 9050 4116 4522 1.10 74810 35
6800 74811 35
(= MM 5314 ; __ 1482025
MM 5316 [4529 95, s#0_ 2
MM MC 14409 14.50 ae aH
TR 16028 3.95 MC 14419 4.85 oo 73
UPD 414 4.95 74C151_ 1.50 —
Z80A 22.50 ei a
L 2 80 17.50 CABLE ADDRESS: ICUSD i) ee
ZBOPIO 10.50 ae fe
Ki 2102 1.45 TELEX # 697827 <_<
2102L 1.75 TMS 4044 9.95 asi 28
= . ; Pa 9 A.M,-6 P.M. MON. thru SUN, —_— a
INTEGRATED CIRCUITS UNLIMITED sist 30
____ 748158 30
7889 Clairemont Mesa Blvd. ¢ San Diego, California 92111 U.S.A. ae = =
NO MINIMUM B13! 2.75
COMMERCIAL AND MANUFACTURING ACCOUNTS INVITED
ALL PRICES IN U.S. DOLLARS. PLEASE ADD POSTAGE TO COVER METHOD DF SHIPPING. SPECIAL DISCOUNTS
ORDERS OVER $100 (U.S.) WILL BE SHIPPED AIR NO CHARGE.
; Total Order Deduct
PAYMENT SUBMITTED WITH ORDER SHOULD BE IN U.S. DOLLARS. $35-$99 10%
ALL IC’S PRIME/GUARANTEED ALL ORDERS SHIPPED SAME DAY RECEIVED. $100-$300 15%
CREDIT CARDS ACCEPTED: $301-$1000 20%
Phone (714) 278-4394 BarclayCard / Access / American Express / BankAmericard / Visa / MasterCharge
@ Circle No. 142
SRACTICAL COMPUTING July 1979 25
Does your computer speak to you?
“WEHL IHT KAAN DOO WIHTH MEE!’
Features
@ Single PCB plugs directly
into an SWPTc 6800 bus.
@9 parameter vocal tract
model.
@ Realtime software
converts any stored
phonetic code to speech.
@ Computer Games.
@ External input for special
musical effects.
@ Adds speech output to
existing BASIC programs.
Microspeech package
@ Speech synthesizer board
(assembled & tested).
@ MSP2 Software on floppy
disc or cassette.
@ Hardware & Software
manual.
@ Speaking BASIC software
option.
TIM ORR DESIGN
CONSULTANT
55 Drive Mansions,
Fulham Road,
London, SW6
Make your computer
talk
Just by entering phonetic
text (as in the sentence at
the top of the page).
Microspeech with the
MSP2 software can make
your computer speak.
MSP2 uses only 4K of
memory. Every extra 1K
of buffer space can store
90 seconds of speech.
It speaks for itself
COSTRONICS
ELECTRONICS
13 Pield Heath
Avenue, Hillingdon,
Middlesex
foronly £99 (*vaT)}
FEATURES:
* 16 lines of 64 characters per line
* On board rectifier and regulator (only needs 12.6V
transformer)
* Full set of 128 ASCII symbols including upper and lower
case and Greek characters
* Full cursor control
* 8 bit ASCII or 5 bit Baudot operation
* 20mA loop opto isolated interface
* Full duplex 110-300 Baud rate interface
* 625 line 1.5V p-p video (will drive UHF modulator)
* Board will interface with standard ASCII keyboards
Comes complete and tested, with detailed manual. Please
send cheque or P.O. for £108.50 {includes VAT, postage and
packing.
7-day money back guarantee, if returned as new.
JILTA MICRO
647 High Road, Seven Kings, Essex G3 8RA
TV GRAPHIC AND ALPHANUMERIC VIDEO RAMS
Intel SBC-80, LSI-11, S100 and general purpose cards,
modules and LS! ICS. Some can be operated together
for colour or TV picture + Alphanumerics or graphics
+ alphanumerics
Eg
MTX 1632 16 rows 32 chars module
ALT 250 x 256 graphics (S100)
MSBC—2480 SBC—80 24 row 80 char
MDC—512 (PDP-11) 512 x 512 graphics
MTX—A1 uPC controller-—KBD + LEDs
26
f 1-off
£162:00
£28400
£35600
£99500
£ 28:00
SHELTON INSTRUMENTS LTD.,
22/24 Copenhagen Street, London N10JD_ ‘Tel: 01-278 6273
pe
PT
pe
@ Circle No. 145
PRACTICAL COMPUTING July 1979
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Circle No. 146
27
PRACTICAL COMPUTING July 1979
THE TRIED AND TESTED Pion MULLIONS
MINICOMPUTER computer YARWELL
SYSTEM a il PETERBOROUGH
THAT EXPANDS Hardware by
_ TO MEET
YOUR NEEDS EQUINOX
SWTPC TEXAS
DIABLO
SPECIFICATION:
*RCA 1802 8-bit microprocessor,
with 256 byte RAM
expandable to 64K bytes
*RCA 1861 video IC to display
program on TV screen via the RF
Modulator
Single Board with
Professional hex keyboard -- fully
decoded to eliminate the waste
of memory for keyboard decoding
circuits
Load, run and memory protect
switches
16 Registers
Interrupt, DMA and ALU
Stable crystal clock
Built in power regulator
5 slot plug in expansion bus
less connectors
BOARD WITH VIDEO OUTPUT
NOW ONLY
£7995 ::°
Software by SOURCE (UK)
ACCOUNTS: PARTS . MAIL: sBasict FOR SWTPC SYSTEMS)
One Day Courses each Month
e Introduction to Micros.
2. 2. ... =
The personal computer division of HL Audio Ltd 138
Kingsland Road, London E2 8BY 01-739 1582
Please send me the iterns ticked below:
e Business Applications.
PROTECHNIC
(Choose either components or wired and tested units) INC. VAT
ELF || KIT COMPLETE WITH FULL WIRING INSTRUCTIONS AND OPERATING
ELF IIKITWIRED AND TESTED 107.95 0780- 782746/'782913
BOWER SUPELY (Gai FOR ELF Ii a @ Circle No. 148
EXPAND YOUR ELF II with the following hardware, a comprehensive range that is belng
continually increased through research and development.
GIANT BOARD KIT — includes a system monitor/editor that works on all 64K bytes of
possible memory; a cassette I/O routine for recording programs on an ordinary cassette;
two 8 bit parallel I/O ports with handshaking for connecting the ELF II to a printer and
ASC II keyboard or any 8 bit parallel interface. The serial RS 232 and 20ma TTY 1/O's
allow connection to printers, terminals or any serial I/O device 37.50
GIANT BOARD WIRED AND TESTED 59.40
4K STATIC RAM BOARD -— Add up to 16K on board. ELF II will accept up to 64K and is : > =
addressable to any page to 64K. Requires ELF tl expansion power supply 75.60
4K STATIC RAM BOARD WIRED AND TESTED 97,15
EXPANSION POWER SUPPLY - required when adding 4K RAM Boards 20.52
ASC II KEYBOARD — Complete with connector to plug directly into the ELF II Giant Board
and is powered by the ELF |! Expansion Power Supply. The ASC II Keyboard follows the
standard typewriter configuration and generates the entire 128 character ASC || upper/
iower case set with 96 printable characters, with onboard regulator, parity logic selection
and 4 handshake signals 54.63
A powerful multi-user
multi-tasking
ASC Il KEYBOARD WIRED AND TESTED 76.22 multi-language
aoe Lee es eit 16.22 1 ee : 7‘
MODULATOR to use with TV 3.00 5-bi i eC I
KLUGE PROTOTYPE BOARD - accepts up to 36 IC's in 40, 24, 18, 16 pin formats with 6 { MICFOCOMPBUISE times prig si Sten,
86 PIN GOLD PLATED CONNECTORS (One required for each add on Board) 4.32 support i ng
ELF t! LIGHT PEN TO WRITE OR DRAW ON TV SCREEN 7.02
BASIC
ALSIP
PASCAL
* Floppy discs
Hard discs
AVAILABLE SHORTLY TO EXTEND THE SCOPE OF YOUR ELF ti:
VIDEO GRAPHICS BOARD
THE SOFTWARE that makes ELF II an ideal machine with which to learn computer
techniques rapidly
ELF Il TINY BASIC CASSETTE TAPE — Makes programming even easier. Commands
include: Save, Load, Let, ff/Then, Print, Goto, Gosub, Return, End, Rem. Clear, List, Run,
Plot, Peek and Poke. TINY BASIC ALSO INCLUDES: 16 bit integer arithmetic + x + ()
and 26 variables A-Z and also comes fully documented with an alphanumeric generator
for direct display on your TV 14.5
ELF-BUG Monitor Cassette eliminates the need to single step through a program to fine
the contents, with the ability to run and edit from any point in the memory 4.58
“SHORT COURSE IN PROGRAMMING’ by Tom Pittman. Written specifically for the EL
(las a Step-by-step course which fully exploits the potential of ELF Il
eiaer COURSE IN TINY BASIC’ by Tom Pittman teaches how to program in Tiny
asic’ 4.00
RCA 1802 Users Manual 4.00
AVAILABLE SHORTLY:
TEXT EDITOR ON CASSETTE, ASSEMBLER ON CASSETTE, DISASSEMBLER ON
CASSETTE
(enclose cheque/PO No. for£
including a powerful Text Formatter,
Assembly Language Development System
and disc-based Sort utilities.
Priced from under £5,000
Write or phone for further information.
(Add £2 post and packing for orders over £20) or charge
Barclaycard No.
Access Card No
Name
EQUINOX COMPUTER SYSTEMS LTD
“Kleeman House” 16 Anning Street.
New Inn Yard. London EC2A 3HB.
Tel:01-739 23879. 01-729 4460.
Address ..;..
SIGUINALUILE: - pmmemen eeussaresse Wee aa veirereeceantuneeen ites
Hours of business: ‘Mon-Fri 9. 30-5.30, Sat 9. 30-1 00,
Dealer Enquiries Welcome
Telephone Orders Accepted 01-739 1582
@ Circle No. 147 @ Circle No. 149
28 PRACTICAL COMPUTING July 1979
Ba er
space available for an onboard regulator 13.82 |
EXPANSION MOTHERBOARD Kit £50
8K STATIC RAM CARD Kit. . . . £97
8K EPROM BOARD Kit. ... . £97
Full details available in our brand new 1979 computer products catalogue,
so order your copy right now! Don’t forget VAT is extra at 8%.
User club £4 per annum.
To: TRANSAM COMPONENTS
LTD., 12 CHAPEL STREET, NW1
Name = : Please send me the following
1 A copy of your latest
catalogue | enclose 30p +
S.A.E.9 x 7
| am interested in the Triton
Address (please print)
=
[_]
[J
[J
1
t
!
t
t
!
! 2 Acopy of the Triton Manual
t l enclose £5 + 70p P & P
1
|
t
!
!
!
!
'
e
3 A complete kit of parts for
Triton Computer, £286 +
VAT + £4P&P
4 A Printed Circuit Board
£50 + VAT & £1 P&P
BARCLAYCARD, ACCESS,
VISA & MASTER CHARGE
ARE WELCOME. SEND
YOUR CARD NUMBER WITH
ORDER
TOTAL ENCLOSED €£......
Cheque, Money Order, etc.
ee
Pe ewww er we eee mew ee Be ee RH wm ew ee Mw emer eH He Re eee eK em eM Ke Ke HO
PRACTICAL COMPUTING July 1979
The exciting new
TRITON
Personal Computer
exclusively from:
Complete kit of parts
available only £286; + vat)
Basic in Rom: a powerful 2k Tiny
basic resident on board, makes
Triton unique, easy to use and
versatile.
Graphics: 64 Graphic characters
as well as full alpha numerics.
Single Board: Holds up to 8k of
memory, 4k RAM and 4k ROM, sup-
plied with 3k ROM and 2k RAM.
Memory Mapping: 2 mode VDU
|/O or memory mapped for animated
graphics.
Cassette Interface: crystal con-
trolled Modern tape I/O with auto
start/stop + ‘‘named” file search.
UHF TV Interface: On board uhf
modulator, plugs into TV aerial
socket.
Comes Complete with KEY-
BOARD, CASE, POWER SUPPLY,
THRO-HOLE PLATED QUALITY
P.C.B. FULL DOCUMENTATION
POWERFUL 1k MONITOR & 2k
TINY BASIC PLUS ALL COM-
PONENTS INCL. IC SOCKETS.
NOTE TV SET & CASSETTE NOT
INCLUDED.
Expansion: Expand your Triton
simply and easily with our new 8-
slot motherboard complete with
its own P.S.U. takes 8 plug-in
Euro cards. Plug-in 8k RAM card
now available.
TRITON HUMBUG VS.|I.
Runs in 4K on main board. Extended Basic includes
peek, poke, read, write, call and edit. New I°5K monitor
has software mod for printer and much more. Youreturn
the eproms from Triton and we supply four new ones,
fully programmed and documented. £25 + VAT, for
details send £1 and SAE.
All components can be bought
separately and eleven packs
can be purchased on an easy-
to-buy scheme. See catalogue.
TRAINSAM
TRANSAM COMPONENTS LTD.
12 CHAPEL STREET, LONDON, NW1
TEL: 402 8137
Next to Edgware Road Tube Station iets Line)
Triton Computer is the Trade Mark of
TRANSAM COMPONENTS LTD.
@ Circle No. 150
29
C. CRYSTAL ELECTRONICS C. |
C RON
8K XTAL BASIC
FOR NASCOM 1
1..Commands:— CALL CLEAR CLOAD CONT. CSAVE READ
.DATA..RESTORE DEF..FN DIM EDIT’ END FOR..TO..STEP..NEXT
GOSUB..RETURN GOTO IF..THEN INPUT LIST NAS NEW
ON..GOTO ON..GOSUB OUT POKE PRINT REM RUN SPEED
STOP WAIT SPC() TAB()
2. Variables:— Names must start with a letter, but can be up to any
length. First two characters used to distinguish one variable from
another. Strings of up to 255 characters, also Multi-Dim, Arrays
and String Arrays. Numbers range from +/— 1E+/—38, with an
accuracy of six significant figures.
3. Functions:— ABS ASC ATN CHR$ COS EXP INP INT LEFT$ LEN
LOG MiID$ PEEK POS RND RIGHTS SGN SIN SIZE SIZE$ SQR
STR$ TAN VAL.
4. Operators:— Arithmetic: + — */** (To the Power of’)
Relational: =< ><> >= <=
Arith-Logical: And Or Not
String: + (Concatenation)
5. Cassette commands:— CSAVE CLOAD for saving and loading
programs. Also CSAVE@ CLOAD@ for saving and loading of
numerical arrays.
6. Special Commands: EDIT ~ Powerful line editor. CALL — Machine-
code subroutine call. NAS — Return to ‘NASBUG’ under software
control. OUT, INP & WAIT — for control of 1/0 ports.
7. Compatibility:— Tape routine provided for use with T2 Monitor.
Fully compatible with T2, T4 & B-Bug Monitors.
8. Size:— Actually fits in 7K of Ram (1000H-2BFFH),But recommend
>=16K Expansion Ram in your system.
9. Availability:— On C12 cassette tape, with documentation.
10. Price £35.00 + VAT.
PROGRAMS BEING WRITTEN NOW READY FOR WHEN THIS
ADVERT IS OUT. PLEASE PHONE FOR DETAILS.
A
FEATURES INCLUDE:
*20 COLUMN PRINTER
*20 CHARACTER
ALPHANUMERIC DISPLAY
*“ FULL 54 KEY TERMINAL-STYLE
KEYBOARD
“TTY INTERFACE
* TWIN CASSETTE INTERFACE
* RAM — 1K TO 4K OPTIONS
OPTIONAL EXTRAS INCLUDE:
8K ‘BASIC’ INTERPRETER ROM APPLE.
— £70.00
4K ASSEMBLER ROM — £59.50
POWER SUPPLY — £41.83
CASE (Including Power Supply)
— £78.00
EXPANSION MOTHERCARD
— £136.50
Pelco (Electronics) Ltd
Enterprise House 83/85 Western Road HOVE East Sussex BN3 1JB
eS
Tel: Brighton (0273) 722155
Buy it with your Access or Barclaycard.
30
NASCOM NATIONAL DISTRIBUTOR TRADE INQ WELCOME.
AIM 65 comes to you fully built
and tested with a full alphanumeric
keyboard. 20 character display
and a 20 column printer — y
for keeping a permanent
record of all your work. Available
in 1K-and 4K-byte RAM versions,
AIM 65 is designed around the
6502 CPU, which has 64K address capability
with 13 addressing modes. This is the
microprocessor at the heart of many other,
more costly, systems such as PET and
AIM 65 has a 4K ROM-resident monitor
program for all peripheral control and user
programming functions, Spare sockets are
included for expanding on-board program
memory via user PROM-based programs
and/or Rockwell assembler, text editor and
BASIC interpreter plug-in options.
AIM 65 has a connector for external
access to system bus for memory and
SW AGENTS
APPLE
COME AND SEE THE. APPLE IT’S WORTH IT_ |
APPLE SOFTWARE AVAILABLE
MANY GAMES - FROM £5.00 TO £15.00 NOW
STOCK CONTROL £100.00 + VAT Now
MAILING LIST £50.00 + VAT NOW
COMPONENT STOCKISTS TO. (VERO STOCKISTS). 74
SERIES, 74 LS SERIES, CMOS, CAPACITORS, RESISTORS,
POTS, BOXES, SEMICONDUCTORS, BOOKS, TOOLS,
TRANSFORMERS, ETC. ETC. + “BEAR BAGS”
BOOKS
6502 MANUAL
280 MICRO HANDBOOK
£7.95 + 35p pp
ST SELLERS
BE ‘ £6.95 + 35p pp
+ MANY MORE
BASIC COMP GAMES £5.95 + 35p pp
NASCOM SOFTWARE AVAILABLE
MINIMUM SYSTEM GAMES TAPE £6.00 + VAT NOW
TINY BASIC GAMES TAPE £12.00 + VAT NOW
C12 TAPES & 53 in. DISKS STOCKED
40 MAGDALENE ROAD
SHOP OPEN TORQUAY
0930-1730 DEVON
EXCEPT: ENGLAND
WED & SUN. Tel: 0803 22699
COMPUTERS
AND
OMPONENTS
@ Circle No. 151
C,
dean
=.
cl
\/(O expansion, a separate connector for
interfacing a teletype and two cassette
recorders. There is a user-dedica ted
Versatile Interface Adaptor, featuring three
8-bit, bidirectional ports (two parallel, one
serial) and two 16-bit interval timer/event
counters — thus allowing the user to
interface his own system, without extra
interface devices in many cases.
AIM 65 is probably the most effective,
low-cost microcomputer development
system available — an invaluable
educational aid to first time users and an
ideal general purpose micro-computer for
the engineer
AIM 65 is available in the UK only from
PELCO ELECTRONICS LTD at £245.50 +
VAT, complete with User's Manualand
Schematic, R6500 Programming and
Hardware Manuals and a handy pocket
reference card.
@ Circle No. 152
PRACTICAL COMPUTING July 1979
The VDU that
fits most micro,
mini and main-
frame systems—
lots of built in
features
Acoustic data
modem speeds up
to 300 bauds—
works either at the
computer or
terminal end of
a datalink.
Provides an economic
solution for companies
with commercial and
data base requirements
Text editor, basic inter-
preter and commercial
packages available,
many packages full
Top quality IBM compatible
single sided floppies plain
label from leading
manufacturer.
PRACTICAL COMPUTING July 1979
THE CUB
An economic
answer to
simple VDU
needs,
64 x 16ch,
cursor control
The feature packed
INTERTUBE compares
with terminals costing
up to three times as
much. Protected fields
page editing. self test,
cursor control, graphics,
28 programmable
function keys—just a
few of the many
features
Probably the
best value
80 col, 112
cps printer on
the market
The portable
hard copy
terminal that’s
built to last—
thousands of
satisfied users.
A proven range of micro
computer systems backed by a
wide selection of software
packages. Has a choice of floppies
or cartridge discs and built-in
screen.
Write or call for details:
Computrade Ltd
Silverwood House, Oxshott Rd.,
Leatherhead, Surrey.
Tel (03723) 79143
or contact your nearest distributor
North 061-477 4960
Midlands 0533-536077
South East 01-658 5906
@ Circle No. 153
31
Jeff Orr and Graham Knott
are now trading as:
Cavineete Oe . 5
oe Dual Drive Floppy Disk
£840 +VAT
%¥ Diskman operating system
% Random & sequential access
* 100k on each drive (200 k
on double density)
2k ex-stock
Expandamem
Memory
Expansion
24k i £320 VA
16k and 32k also available
All ex-stock
Undirectional interface I-EEE to RS232 £89 + VAT :
Bi-directional interfaces, 1 or 2 port,and A/D convertors ao
‘COM ER
also available. SERVICES
PUT
We also supply:
Commodore Pet complete range. Peripherals SS
software and manuals. Petsoft, CBM and STACK 625 Video Adaptors
software. for Pet £29 +VAT
Apple Il 16k, 32k or 48k Joystick £25 +VAT
mini-disk drives, interface cards and software.
ITT 2020 16k, 32k or 48k . Page Printer Interface
plus all peripherals (20m A loop) £95 VAT
Printers Centronics 779, Perkins Elmer Pussycat
Teletype 43 etc., including interfaces and stationery. ex-stock
PHONE US ON
Stack Computer Services is the
trading name of Mardonstar
fi Ltd.
All prices are --VAT at 8% and
include carriage. Please make
i payable to Mardonstar
td.
for details of our catalogue or write to
Stack Computer Services, 1 Westward View, Waterloo, Liverpool
@ Circle No. 154
32 PRACTICAL COMPUTING July 1979
SS eT NE ac Se
Publisher’s
‘Letter
READERS whose memories stretch for a
year — a long time in microcomputers -—
will recall that what is now the Mic-
rocomputer Show was last year the Do-
It-Yourself Computer Show. Then, too,
Practical Computing contained the offi-
cial Show Guide.
That 60-page issue was sold out very
quickly and is now a much-sought-after
collectors’ item. This year’s bumper
Show Edition contains 136 pages but the
price remains at the original 50p.
It is not just Practical Computing
which has grown so dramatically in the
last year but also, as will be particularly
obvious to Show visitors, the whole
microcomputer industry.
You will be faced with a tremendous
choice of very sophisticated hardware.
To some it might seem a bewildering
choice, and it would be worthwhile
studying our guide to buying your first
computer (page 53) before making such
a momentous decision.
Assimilating the latest Practical Com-
| puting Buyers’ Guide (page 125) and
stand-by-stand review (page 63) should
then enable you to focus your attention
on where your time, and eventually your
money, is best spent at the Bloomsbury
Centre from July 5-7.
Enjoy the show, buy wisely, and by all
means visit our stand to browse through
the back numbers or to talk to the people
who make this your magazine.
PRACTICAL COMPUTING July 1979
Our Feedback columns offer readers the opportunity of
bringing their computing experience and problems to the
attention of others, as well as to seek our advice or to make
suggestions, which we are always happy to receive. Make
sure you use Feedback—it is your chance to keep in touch.
User groups
WE are aware that there are about 30
members of the ACC in our area but
from the regular appearance of your
magazine in newsagents we suspect that
there are many people “going it alone”’.
We would find regular exposure in a
“User Groups Page” very helpful. If
space is a problem a diary would be
acceptable.
Our one Tandy owner was pleased to
find the TRS-80 Forum in Practical
Computing and in view of this I am
surprised that you do not exploit the 10K
or so Nascom owners — not me, I have a
6800 -— by having regular programs for
them; likewise, the other popular
systems.
On the subject of software, would it
not be possible to have all machine code
cross-compiled to cover all the common
processors, and also to detail changes of
Basic programs for different machines?
Finally, since several of our members
know nothing of the general electronics
hobby press, it might be helpful if
components suppliers advertised in your
magazine.
N. P. Butcher
Bushey Heath, Watford.
Initial system
I WOULD be grateful for your advice on an
initial computer system for hobby/
scientific/possible commercial use which
may be expanded into a multi-user
system at a later stage:
Cost, £2,000 including VAT;
Memory initially 32K, expandable to
64K;
Fortran IV, Assembler, Basic, Algol and,
eventually Cobol;
Dual floppies, CP/M operating system,
file-orientated, IBM-compatible, 8in or
256K to run _ reasonable-size Fortran
programs;
To reduce initial costs, printer and
possibly VDU to be added later; if a
VDU has to be obtained - no UHF TV
output — which ones are best suited to 80-
character screen width?
Graphics capability later, high resolution;
later, input/output paper tape or cassette;
good quality documentation, reliability —
little or no maintenance costs; low power
consumption - not affected by mains
variation;
Where can discounts be obtained?
Summing up, maximum reliability and
expansion, plus performance, for
minimum cost. M. J. Stalker
Farnborough, Hants.
Bank switching
I WAS interested to note Allen Secker’s
letter in your April issue and your
comment concerning the availability of
bank switching boards.
I am a main importer for Imsai in
South-east England and can confirm that
Imsai has now discontinued manufactur-
ing the IMM bank switching board which
permitted megabyte addressing.
As I understand it, there was insuffi-
cient demand on the American market
for such a facility on microcomputers.
There are, however, doubtless dealers in
the U.S. who have stocks of this board;
and if any individual or company requests
it, I will gladly attempt to trace one.
Imsai is concentrating on the VDP and |
PCS microcomputers.
Graham Jenkins
Corner Computing Services
Epsom.
@ Apart from that, we hear also that
Imsai recently filed for Chapter 11 bank-
ruptcy protection. This is a provision in
the U.S. legal code which gives a company
a few months to put its affairs into order,
if it can.
On the other hand, we have also heard
from another Imsai distributor, Compu-
ter Mart of Norwich. ‘‘In answer to your
comments on bank-switched memory
boards, we. handle all products made by
Imsai.
‘*Bank-switched memories are available
in three sizes: 16K @ £500 + VAT; 32K
@ £867 + VAT; 64K @ £1698 + VAT.
Please check with our office for prices”’.
Educational software
IAM a psychologist working in the field of
employment rehabilitation and am seek-
ing information on educational software
packages suitable for commercially-
available micros. My interests range from
computer-assisted education in simple
arithmetical skills to the teaching of basic
computer programming. Any informa-
tion would be most gratefully received.
Peter Spencer
Employment Rehabilitation Centre
Dovedale Avenue
Ingol, Preston.
(continued on page 35)
33
OTUS
34
Pet Expansion
Computhink
Dual drive
minifloppy
Complete with 4K disk operating system in ROM,
plugs into Expandapet memory. Adds 15 new com-
mands to Pet’s Basic to give full disk extended Basic.
Loads 8K in 2.6 seconds. Automatic reorganisation
of free space. Utility Disk
£833.47.
Expandapet memory
Powered by Pet’s own powersupply and mounted
internally in 5-10 minutes without special tools.
ees £261 +V.A.T.
P| ener pateaeady se fee eas YO £320. V.A.T.
Soe. ses £374. V.A.T.
Alt units are fully built and tested.
Super Board Il
pe
gui eee
“pt rbot
pce
A a4 sent
“sneme HE
.
—_—-
This 6502 based microcomputer comes with a full
8K Microsoft basic in ROM. Full keyboard. 4K static
user RAM (on board expandable to 8K). Kansas City
standard interface for use with an ordinary cassette
recorder. Machine code monitor and 1/0 utilities in
ROM. Direct Video access with 1K dedicated RAM
(besides 4K user RAM) and full graphics set.
Fully built and tested only needs a 5V 3amp power
supply and T.V. Monitor or R.F. modulator to be up
and running. £263.84 +V.A.T.
Apple || was the original with full colour high resolution
microcomputer Basic, and it is still the best. With a
very wide range of expansion available, including disk
drive, interface cards, voice recognition card, light pen
and many others.
Apple || has been well tried and approved by the public
(over 200,000 sold) because of its thoroughly pro-
fessional design and high quality engineering. You
cannot get better value for money. Please send us a large
s.a.e. for further details.
£ 820 +V.A.T.
With 16K user RAM only
Applell &TRS8O
Memory Expansion
Save Over £100
TRS 80 and Apple I! memory expansion kits. Fully
guaranteed and with full specification 4116 16K RAMs.
Kits come with full instructions and new jumper sets
where necessary. Fitting takes 5-10 minutes, or bring
along your Apple or TRS 80 and we will fit it for you
for £5.
16K upgrade kit £85 + V.A.T.
U n) >» 4 MORGAN STREET TELEPHONE:01:981 3993
LONDON E3 5AB TELEX: 261426 ATN. LOTUS SOUND
PRACTICAL COMPUTING July 1979
@ Circle No. 155
(continued from page 33)
North Star plea
HAVING had certain problems with
understanding North Star Basic manuals,
it occurs to me that it would be useful to
get in touch with other North Star users
so that there may be a pooling of
experience and ideas.
If any of your readers would be
interested, please could they contact me?
J. L. A. Cary
Venture Capital Report Ltd
2 The Mail
Clifton, Bristol BS8 4DR.
Unsung
THIS neat Basic game arrived without a
covering letter but it should help while |
away the occasional wet evening:
10 REM NPBF11 SEQUENCE GAME.
20 PRINT “TYPE ME FiVE NUMBERS IN A SEQUENCE™
30. PRINT “I WILL GUESS THE SIXTH. EXAMPLE 2, 4, 6, 8, 10"
4 =DIM X (10)
50. INPUT A,B,C,D,E
F=(O- (X(1) *2)) + (X(2) *5) + (O- (X(3) *2)) + (- (X(4) °4)) +
55 XG)=E
70 PRINT A; B; C; D; E; “("5F;")"
80 PRINT TAB (23), MY GUESS";'“1S IT RIGHT?
TYPE YES OR NO"
90 INPUT AS
100 iF A$ = “YES” THEN 1 40
110 PRINT
PRINT
PRINT “THAT WAS EASY”
PRINT
PRINT “DO YOU WANT ANOTHER GO? TYPE YES OR NO”
INPUT AS
IF AS = “NO” THEN | 0
PRINT
PRINT “TYPE ME ANOTHER SEQUENCE”
GOTO Su
65 PRINT
35 PRINT
END
B. H. Field
Fordingbridge, Hants.
Far and wide
HAVING just received a copy of the
March, 1979 issue, I decided a personal
subscription was essential. I especially
enjoyed reading Tandy Forum. I have a
TRS-80 Level II 16K microcomputer —
believe it or not there are three such units
in Tripoli.
I have a few comments and questions:
@ Is it possible to have a series of
articles on assembly language program-
ming for the beginner?
@ Tandy Forum refers to Optronics and
J & J Electronics. For readers outside the
U.K. an address or two would be helpful.
@ Is an index available for Volume 1 of
Practical Computing?
Dr Anthony P. Schmitt
Petroleum Research Centre
Tripoli, Libya.
@ Having readers in Tripoli must be akin
to success. We are considering authors for
a series on assembly language program-
ming which we would start in the
Autumn. We are also computerising our
index and will print a cumulative index
soon. We take the point about addresses;
in future we will give them.
‘PRACTICAL COMPUTING July 1979
Bewildered
HAS Commodore boobed? I refer to the
new 16K Pet with large keyboard. Cer-
tainly I like the look of the machine, and
the resident monitor is most useful for
anyone in the machine code environ-
ment, although the manual I had with the
unit didn’t explain how to call Monitor.
I must thank my local supplier, HB
Computers of Kettering, for help in
finding the magical instruction which is
SYS (64785) - and also for explaining
that some of the Basic subroutines are
different on the new models.
After finding that several programs
written for the 8K Pets didn’t work on the
16K, however, I looked closer at the
memory map to find that most of the
zero-page locations have been changed.
Perhaps Commodore was aiming for
an improved ROM - but it has proved to
be a disaster for me and, I suspect, other
users. Any machine code programs which
change various pointers in zero-page or
programs which make use of free areas of
zero-page will almost certainly go hay-
wire. Microchess 2, for instance, does not
work.
Another annoying fact is that the
upper- and lower-case configuration has
been changed. On the 8K models, a
POKE 59468,/4 will change graphics into
lower-case and leave the upper-case
characters as they were, but on the new
16K model the same command causes
graphics to become upper-case and the
upper-case to become lower-case. A
program containing lower-case output
really looks odd on this machine.
If you are now suitably confused, join
the club; I’m still bewildered and would
look forward to any comments from
Commodore.
V. A. Withnall’
Rushden, Northamptonshire.
For new owners
| | HAVE recently started a club for owners
of SC/MP based machines like the Mk 14.
Initially, the club consists of a circulating
newsletter to which ideas and programs
can be added by members.
For anyone who is interested, I would
be glad to add names to the existing
circulation list. The object of the newslet-
ter is to help new owners to get to grips
with their machine and provide a means
of communication between members.
Geoff Philips
_ 8 Poolsford Road
London NW9 6HP.
Suggestions
I WOULD like to suggest two additions to
your magazine — a Hardware at Chip
Level section for those who wish to build
or modify their own computers, and a
readers’ advertisements section for those
| Easy solution
a
wishing to buy or sell computers, chips or
software.
I have a personal interest in both of
these since I have acquired for £10 a 16-
bit minicomputer complete with high-
speed optical paper tape reader but
without keyboard, VDU, printer, or
other human interfaces. There is one |
major snag — all the manuals are in
Japanese, so I am thinking of taking out
the CPU and replacing it with a micro (Z-
80) but using the existing power supplies
and memory - 12K x 16 bits = 24K x 8
bits of old-fashioned non-volatile core
memory.
I have a Honeywell 8100 instrumenta-
tion tape deck which needs attention/
rebuilding of the signal processing cir-
cuits. It is a sin. wide tape, 103in. NAB |
spool capacity, four-speed (1%, 33,15, 30
ips) eight-channel machine with fully
working tape transport (three motors),
but I haven’t the time to do what is
necessary.
If anyone would like to take it for the
giveaway price of £60, including five
tapes, I shall send a donation to Practical
Computing. Two other damaged tape
decks (three motors each) are also
available for £15 the pair.
I enjoy the magazine and wish you well
in your contribution to smashing the
barriers of ignorance and fear about
micros.
Finally, I would like to contact Jack
Pike (Feedback, May) of Chawston,
Bedfordshire about his Adventure II
game and to inform him that I am
working on a text-packing routine requir-
ing two bytes per written word with
automatic spacing and the facility to
insert standard ASCII codes at any point
in such text, except in mid-word.
John E, Foggitt
Stony Stratford
Milton Keynes, Bucks
IF SOME Of your readers are, like myself,
fellow Nascom users but are tired of
waiting for Nascom to produce a decent-
size Basic interpreter, as opposed to its
Tiny Basic, they might be interested in an
8K Basic which I have found, available
on tape, from my local computer shop -
Crystal Electronics of Torquay.
Although not an ideal solution, it eats
into RAM - the facilities of an 8K
Basic, including extensive string handling |
and floating point maths, transforms
Nascom to bring it on a par with Pet and/
or Tandy TRS-80.
M. Dwyer
Malborough, Kingsbridge, Devon
35
Prepare for arrival of world’s
fastest eight-bit micro
INTEL is about to announce the
8088, the world’s fastest eight-
bit microprocessor. ‘Fast’
refers simply to the amount of
work it can accomplish.
The point about the 8088 is
that it combines some of the
virtues of the Intel 16-bit chip
set, the 8086, with many of the
more desirable attributes of
eight-bit Intel micros.
The 8086 has a 16-bit inter-
nal architecture — much faster
internal operation than an
eight-bit processor, full
software compatibility with
the 8086, and a clever instruc-
tion set which allows programs
to be used with other eight-bit
machines.
The 8088 can process eight-
or 16-bit data in single, string,
or block form; and 20-bit
addressing means it can access
directly up to one megabyte of
memory. There are 24 addres-
sing modes, which will ease
the programmer’s task and
facilitate development of more
efficient program code.
The 8088 contains many
hardware arithmetic instruc-
tions but in addition to its
number-crunching
capabilities, there are many
string operations specifically
intended for alphanumerics —
block moves, string compari-
sons, data scans, data transla-
tions. Internally, the 8088
looks well set-up for word
processing and business equip-
ment applications.
A 16-bit data bus has, in
Over-the-counter
market survey
THE Frost & Sullivan opus The |
Over-the-Counter Computer
Market predicts an eight-fold
growth in the business done by
retail outlets, from $250 mil-
lion in 1977 to $2 billion in
1985.
The researchers reckon that
the so-called hobby shop will
become the normal mode of
distribution to end-users, al-
though the hobbyist compo-
nent among the customer base
| is about at its peak.
More growth is due from
small business, the educational
end, and other establishments;
the big boom is forecast in the
consumer sector.
This is how F&S sees the
revenue split in percentage
terms for the immediate
future:
1978 1981 1985
Establishments 66 48 55
Hobbyists 2, 10 5
Consumer 12 42 40
Add-on purchases run from
1.5 times to twice the initial
investment so there’s an op-
portunity for peripheral
makers. “Software is the cru-
cial variable” in buying deci-
sions, so there may be scope
there, too.
F&S reckons that the aver-
36
age annual turnover of compu-
ter stores is about $255,000
now. Strategic Business Ser-
vices agrees, more or less, with
a 1977 figure at $220,000.
SBS isn’t afraid to list the
restricting factors, like capital
limitations, geographic satura-
tion, and the _ technological
developments in distributed
computing. It still estimates a
40 percent annual growth rate,
to reach total revenues of $945
million by 1983. That’s a little
more pessimistic than Frost &
Sullivan. Q@
theory, twice the bandwith of
an eight-bit bus; but, like the
8086, the 8088 has an ‘instruc-
tion look-ahead’ feature, an
instruction queue which in-
creases the efficient utilisation
of the data bus. Throughout
comparisons then become
applications-dependent but
Intel says that, typically, the
eight-bit 8088 will manage 70
percent of the throughput of
the 16-bit 8086.
Intel retained an eight-bit
bus structure to maintain com-
patibility with existing
hardware; ‘an eight-bit board
can be re-designed and up-
graded without changing back-
planes, connectors, memory
structure, or peripheral con-
trollers. A bus eight bits wide
also offers savings in drivers,
transceivers and board space.
You can use the many
multiple-function devices al-
ready available for the eight-
bit family.
Despite the intellectual en-
thusiasm for 16-bit micros,
there are many applications
for which they are unnecessar-
ily powerful — personal com-
puting is probably one. On the
other hand, it would be pleas-
ant to have 16-bit throughput
if you did not have to pay 16-
bit prices and wait for the
development of 16-bit support
chips.
We expect to see the Intel
8088 appearing in many new
products. B
Infectious
enthusiasm
ENTHUSIASM generated for the
6502 from the 6502 Program
Exchange is infectious, par-
ticularly if you possess a Sym,
Kim, Pet, Apple ITT 2020,
Jolt, or Ohio Scientific micro-
computer.
The Program Exchange lives
up to its name. The latest
newsletter dwells at length on
XPLO, a compiler language
which outperformed the Ohio
Scientific Basic dramatically in
a 1977 Kilobaud test.
We like the look of XPLO
because it has many of the
virtues of Pascal — intermedi-
ate code, simple to understand
the principles, highly struc-
tured format — without the
disadvantages. It is easy to
understand the code in XPLO
— unlimited procedure names
help, too — and in general it
looks a friendly language.
Does anyone use it? If not,
$50 buys a cassette and
manual.
Other offerings from the
Exchange include a kind of
super-Focal called FCL-65 - a
step up from Basic or Fortran.
There is Tiny Basic, of course,
for a bargain $10, and a good-
looking Experimenters Manual
for $15. There are several
games and systems programs
at bargain prices, including the
classic Wumpus in machine
language for Kim or Sym.
The 6502 Program Ex- |
change is at 2920 Moana,
Reno, NV89509, U.S. Contact
the company before sending
money. B
Newsletter for Sorcerer
SUBSCRIPTION orders are being
sought for what we understand
to be the only independent
user newsletter dedicated to
the Exidy Sorcerer. The first
issue will be available shortly.
Its name is Source and its
contents are promised to be
items of general interest to
Sorcerer owners, program list-
ings, how-to-do-it articles,
hardware and software re-
views, and letters from
readers.
The publisher is a Michigan
firm which already produces
The Paper for owners of the
Commodore Pet, Rainbow
(for Apple II owners) and The
Viper (dedicated to the RCA
Cosmac VIP).
“Our intention is to provide
useful information at all levels
of expertise,” Aresco de-
clares. ‘Many publications
offer information incompre-
hensible to beginners and to
intermediate level computer-
ists.
‘‘Aresco policy is that
people have to start from the
beginning and there’s no place
for them to obtain beginner-
level information. Then the
intermediate people are stuck,
because the ‘‘hacker”’ informa-
tion is too technical to be
comprehended without an ex-
tensive knowledge of elec-
tronics machine language.
Orders for the Source should
be sent to Aresco, PO Box
1142, Columbia MD 21044.
Master Charge (Access) and
Visa (Barclaycard) are ac-
cepted. Overseas subscriptions
are $25 including airmail post-
age if desired.
Following our review of the
Exidy Sorcerer in May, we
hear that S Gimblett of HMS
Neptune, Faslane,
Helensburgh, Dumbarton-
shire G84 8HL is trying to start
a U.K. user’s group. Contact
him if you want to partici-
pate. =
PRACTICAL COMPUTING July 1979
All ship-shape and Bristol
fashion for Image Data
BRISTOL seems rapidly to be
becoming the Tottenham
Court Road of the U.K. Image
Data has opened a headquar-
ters and manufacturing facility
there.
The British-owned company
will be manufacturing its
Image Data Eight microcom-
puter and the facility is ex-
pected to create more than 100
jobs for electronic assemblers,
all to be recruited locally.
The microcomputer was de-
signed and produced originally
as a development system for
Image Data but it found |
market appeal, so the com-
pany decided to produce it in
quantity and is increasing pro-
duction from 20 to 100 systems
a month.
It is built around a series of
printed circuit boards and pro-
8085 processors compatible
with other PCBs in the bus
system.
There are two systems ac-
commodating six and 12
boards which offer 4K and 8K
RAM, 1K increments of
ROM, CRT, keyboard, Tele-
type I/O, cassette interfaces
and line printer output. Max-
imum storage is 40K RAM
and 24K ROM. A floppy disc
board will follow.
The Image Data Eight
houses the processor in a cage
}
design which the company be-
lieves will appeal to the educa-
tion market, where it can be
sold as a construction kit. The
end-user, OEM and “the high
end of the hobbyist market”
will provide the rest of the
customer base.
Software includes 8K Basic,
Editor and Assembler pro-
grams, resident monitor for all
peripherals, and diagnostic
support for cassettes. After-
sales support is available with
Motorola tests
FIRST successful tests on parts
of the Motorola 64K RAM
have been carried out at ICL.
‘“‘The Motorola samples
worked perfectly’, said Bill
Talbot, ICL technical director,
| who was described by a
vides Motorola 6800 and Intel |
“ee
Motorola spokesman as
hard man to please”’.
It looks as though Motorola
will be first in the great 64K
RAM race but industry pun-
dits believe the device is not as
far advanced as Motorola
might suggest.
ICL admits that it will take
some months before all checks
have been carried out and it is
totally satisfied with the
product.
The Japanese firm, Hitachi,
is likely to second-source
M68000 microprocessor pro-
a
Pascal developed
for SWTP 6800
THERE ARE many very clever
and very enthusiastic micro-
orientated people in the
Netherlands. Some of them
are part of Lucidata and they
have developed a Pascal for
the SWTP 6800.
By popular request, we are
preparing an item on the pros
and cons of Pascal as a high-
level language; it does particu-
larly well as an alternative to
Basic, its advocates say.
For this one you need the
SWTP system — or an equiva-
lent M6800-based microcom-
puter -— running the TSC
FLEX 1.0 operating with a
mini-floppy disc and 16KB
(more memory means faster
execution).
i
The run-time system inter-
faces with FLEX. It includes a
paging facility which is in-
voked automatically if there is
insufficient real memory for a
large program.
In a 32KB system with dual
floppy discs, Pascal programs
can be compiled at more than
80 lines per minute according
to Lucidata. With only 16K
bytes, compilation is at 35
lines per minute under the
paging mode. Programs are
claimed to execute “tens of
times faster” than with con-
ventional interpreters.
Further details from Lucida-
ta, Oosteinde 223, Vourburg
2271 EG (ZH), Nether-
lands. |
‘PRACTICAL COMPUTING July 1979
high-level 6809.
a 24-hour turnround of re-
placement boards.
Cost range is from £500 to
£2,500, depending on
peripherals and model size.
Only a few PCBs are needed
for a minimum system, and
expansion does not enforce
scrapping earlier investments.
The Image Data Eight is
available only from Image
Data at 1-4, Portland Square,
Bristol, BS2 8RR. Tel 0272
40248/9. a
Comart was
neglected
OUR review of the North Star
Horizon homed-in on one of |
the major U.K. dealers but |
neglected the other. Comart in
Huntingdon has the Horizon,
it also sells the Processor
Technology Sol — reviewed in
this issue — and the Cromemco
range (the Z-2D was reviewed
in February). Hi
Comart offers nationwide
maintenance cover by virtue of
its contract with the specialist
service organisation CFM. It
also has nine distributors. &
ducts. Hitachi will manufac-
ture the range of products
which the new processor will
create.
The processor is of an ad-
vanced 16-bit design for high-
level language implementation
with 32-bit internal processing
capability.
The second Motorola semi-
nar, Microcomputer Forum —
last year called Micro Forum
until the Business Equipment
Trade Association claimed
copyright on the name, hence
the change — took place last
month at the Institution of
Electrical Engineers, Savoy
Place, London, and the focus
of attention was the 6800
processor.
Five top Motorola men dis-
cussed all the latest micro-
processors and memories, ap-
plications of the single chip
6801 microcomputer and the
a
Price list
RAPID RECALL has published a
comprehensive price list which
provides details of microcom-
puter, memory, analogue and
data acquisition equipment
from Digital Equipment Cor-
poration, Intel, Intersil, Opto
22 and ITT.
The list is organised by
product group rather than by
manufacturer, which makes it
easy for you to identify the
system or component you
might be seeking.
The price list is available at
£1 from Rapid Recall, 6 Soho
Mills, Wooburn Green,
Bucks. If you buy something
from Rapid Recall it is free.
Converting
1/O devices
PROLIFERATION Of electric ty-
pewriters has for some time
encouraged people to convert
them for use as I/O devices on
personal computers.
Now a U.S. company,
Rochester Data, has a device,
I/O Pak, which fits over a
typewriter keyboard - you
affix two mountings to hold it
in place. The I/O Pak com-
prises a bank of solenoids
mounted in an array which fits
directly over the keyboard of
the typewriter. Energising a
specific solenoid causes a
specific typewriter key to be
depressed, thus printing 4
character.
Electrical actuation of the
solenoid is done by self-
contained drive electronics
which operate in response to
the selection of a pair of one-
out-of-eight control lines.
The unit is claimed to oper-
ate virtually any electric type-
writer with powered function
keys with no mechanical mod-
ifications to the typewriter. All
adjustments are self-contained
in the I/O Pak, for which is
claimed easy initial installa-
tion, ‘‘instant detachability
and replacement”, ‘modest
power consumption and “high
reliability”’. <
The interface appears to be
a six-bit parallel one, and
naturally you, or your compu-
ter, have to provide some
external timing.
The I/O Pak cost $395 from
Rochester Data, 3100 Monroe
Avenue, Rochester, NY
14618. @
37
WITH the introduction of higher-density
memory components, a new group of
single-board computers is emerging.
They do not exactly constitute the
method of operation, and designs are not
so different from previous boards to
justify this label.
The AIM-65, produced by Rockwell
and available here from Pelco Elec-
tronics, is one of this group. Strangely
enough, the newer systems, which in- |
| clude the Ohio Superboard II and the
Synertek Sym 1, all use the 6502 micro-
| processor, as utilised in the Pet and
| Apple II.
Again, like the Ohio Superboard (re-
viewed in Practical Computing, June,
1979) the reputation of the AIM-65
precedes it to some extent. It has been |
hailed as ‘‘the best-engineered cheap
| 6502-based system”.
Facilities
The AIM-65 is a single-board computer
| offering as the input device a 54-key
alphanumeric keyboard in the standard
QWERTY typewriter layout. Also on the
board is a 20-character alphanumeric
LED strip display and a column thermal
printer.
The processor is the Rockwell 6502 |
running with a clock speed of 1MHz and |
an 8K monitor in ROM, plus 1KB of user
RAM; the user memory is expandable
on-board to 4K. An audio cassette
interface programmable for two tape
recording formats is also provided.
| Setting-up
The AIM-6S is_a fully-assembled unit.
“It requires only the connection of the
| keyboard to the computer board via a
ribbon cable and i.c. ‘headers’ — they did |
not seem to be very robust and required |
careful handling.
For power, the AIM-65 requires a
single SV supply at two amps to work; but
to have printer operation, a separate 24V
supply at 2.5 amps is required, which is
not very convenient.
In use
With the SV supply attached, at switch-
on the AIM-65 does a ‘power-on re-set’.
The display ‘ROCKWELL AIM-65" ap- |
pears momentarily on the LEDs, fol-
lowed by ‘PRINTER DOWN’. At that
stage it is ready to accept commands via
the keyboard or a Teletype — this is
switch-selectable on the computer board.
The 54-key keyboard has a very good
feel and because it is separate from the
main board it can, in theory, be
positioned for fast and comfortable
typing. Because the connecting ribbon
cable is very short, however, this is not so
easy.
The 20-character alphanumeric display
is clear in normal room lighting and the
38
{
|
}
|
AIM-65 only cheap |
built-in pri
characters are easy to read, even if a few
of them are a little contorted. The display
uses 16-segment LEDs and for this
reason is upper-case only.
Firmware
Two 4K-byte ROMs of the 2332 type
contain the monitor and utility firmware.
This monitor is very impressive. It does
the usual display/change memory or
registers, start execution and tape dump/
load.
What makes the AIM-65 outstanding
is its powerful debugging package. It
allows the user to set up to four software
breakpoints and under single-step opera-
tion — switch-selectable on the board - it
can do an instruction trace and a register
contents trace, with automatic disassem-
—
by Vincent Tseng
bly on the machine code into assembly
instruction mnemonics, as the user prog-
ram is stepped through.
There is also a program counter history
| command which lists the last four ad-
dresses executed. As it does this in the
single-step mode and as both the instruc-
tion trace command Z and register trace
V print the program counter address, it
seems a little superfluous.
Entry of a program can be in
mnemonics as there is a direct assembler.
It makes life easier than entering machine
hex code, although this is also available if
you fee] masochistic. Because it is a direct
assembler, labels cannot be used; ad-
dresses, therefore, are absolute.
Text editor
To examine a program there is a
disassembler, so that instructions can be
displayed in the assembler mnemonics.
As if all that was not enough, there is also
a text editor with a reasonable set of
commands. It allows the creation of text
and message files, or it can cater for the
preparation of assembler programs to use
with the optional extra ROM assembler.
The commands are limited but are
certainly enough for use; there is a
powerful ‘find string’ function, although
operation will start only from the current
line.
All this can make program preparation
hard work - even though the commands
worked at a fairly high level ~ if we were
limited to the 20-character LED display.
If you want to examine a program and
{
H
| very quickly and only the tenth will be
have it disassembled for 10 instructions,
the AIM-65 will do it, but the first nine of
them will be flashed on to the display
left in view.
To examine 10 instructions in a more
leisurely manner you have to use the K
command to disassemble and enter the
hex address of the instruction, when the
monitor returns with the prompt (a
slash), you enter 01 for one instruction
and repeat all this nine times.
So the AIM-65 really scores when the |
printer is operational, which means you
hear that 24V power supply.
Printer
The 20-column thermal matrix printer
uses a roll of 2 in. (50cm) wide paper. The
print quality is good, and it can output at
approximately 90 lines per minute.
Power consumption we metered was
0.05 amps when idle, peaking to approxi-
mately 0.25 amps during a print cycle.
The meter may well have been slow in
response but there’s certainly a discre-
pancy between this and the Rockwell-
specified power rating of 0.5A when idle
and 2.5 amps.
Another point worth noting was that
the 24V power supply used with the
printer was limited by current on our
system to 1A and at no time did it look
distressed, even during a long print cycle.
So the quoted power rating required for
the printer may be something of an
over-kill in the specifications, or perhaps
Rockwell put the decimal point in the
wrong place. Certainly a 24V 0.25 amp
power supply is much more convenient
than a 24V 2Samp supply.
Paper loading
Paper loading is easy once you know
how, but try to find out how in the users’
guide and the roll seems to last and last.
One tends to forget how very useful it
is to be able to refer back to what has
been done — a printer allows you to do
this. Messages and reminders can also be
printed by involving the text editor —
using a small buffer area if memory space
is tight — editing and printing line by line.
The character set available to the
printer is small and there is a
wraparound. Our demonstration prog-
ram of the printer output and character
set also illustrates the use of the printer
for printer comments and messages.
PRACTICAL COMPUTING July 1979
nicro with
iter
Cassette interface
The audio cassette tape interface
boasts two recording formats, one at a
standard 1,200 baud and the other a Kim-
1 compatible version. The tape recorder
has to be connected via the board’s
‘application’ edge connector J1 but sadly
no edge connector socket was supplied on
our kit, and it is not good practice to
solder directly on to the board’s edge
connector gold-plated fingers. Your re-
viewer, fortunately, was able to comman-
deer an edge-connector socket from a
Kim-1 and connected the AIM-65 to a
cassette recorder.
The AIM-65 does not record and play
| back well with cassette recorders with
| automatic recording level controls. This
restriction probably covers almost all the
current cheap cassette units; it applied to
ours, and we confirmed this with other
users. Apparently, the AIM-65 needs a
manual recording level to overcome the
slow time response of the ‘automatic level
control’ recorder.
Inconsistent
The setting-up procedure and ‘Sync’
program in Section 9 of the Users’
Manual was tried. This could be set up —
adjusting VR1 - so that almost the full
range of the playback volume control was
accepted by the ‘Sync’ program.
When data was recorded it was very
inconsistent on loading and playback. |
Data recording was tried with both
formats and various impedence-matching
resistors were used, but all to no avail.
This was particularly disappointing
because the AIM-65 has some file-
handling capability we wanted to exer-
cise. A user’s file name can be given — up
to five characters — and on playback the
AIM-65 will search for the file name. At
1,200 baud, recording and playback for
256 bytes was fairly fast.
Two recorders
Remote start/stop controls are also
available, so that two recorders can be
used — one set to record, one for
playback. This is suggested for use with
the optional extra assembler in ROM. It
is a pity it does not work well with cheap
recorders.
The edge connector, incidentally, is the
same as for the Kim-1 — a double-sided
44-pin connector with 4mm pitch.
There appears at first sight to be a
fairly weighty documentation pack with
| the AIM-65, but the most useful and
PRACTICAL COMPUTING July 1979
}
relevant ones are the AIM-65 Users’
Guide of almost 500 pages, the 6500
| programmers’ reference card and the
AIM-65 Monitor Listings.
The two other substantial books are |
reference manuals for the 6502 and not
specifically for the AIM-65.
The Users’ Guide has all the informa-
tion, but it is not very well laid-out. For
example, to try to find how to load
printer paper from the index, you might
reach page 1-14 by yourself; on it there
are instructions on how to load the paper,
but no diagram showing where the
relevant parts are located. That is on
pages 11-15 in the chapter covering |
troubleshooting, warranty and servicing.
Similarily for the cassette, Section 2.9
States: “‘We assume that the cassette
recorder has been attached previously in
position 1 according to the instruction in
section 9”’.
There are, however, a few examples,
but not enough programming examples,
and a listing of a useful sub-monitor with
many extra facilities, but it uses some 457
bytes; and as the available user’s RAM
area on a 1K model is only 512 bytes,
memory expansion is needed for this to
be useful.
Compensation
Overall, the documentation at least has
all the relevant information but it is not
easy to follow for a first-time user and is a
headache for pure reference usage.
| Kim programs use subroutines in the
It’s a pity we were not able to test the
AIM-65 with the Basic-in-ROM option
because this would have taken the prog-
ramming to a quicker, higher level.
Ideally, we would prefer to have a TV
interface as well, but the printer compen-
sates to some extent for this.
It has been claimed that the AIM-65 is
hardware-compatible with the Kim-1 — |
and therefore the Synertek Sym-1, too.
This could mean that a TV interface
available for the Kim-1 could be used
with the AIM-65 but it is expensive and
the software interfacing would be
tedious.
The Kim-1 tape format is not that
useful, either, because many of the better
Kim-1 ROM monitor which is obviously
different from the AIM.
Conclusions
@This is the only cheap microcomputer
with its own built-in printer. It is a
worthwhile microcomputer offering the
right types of facilities. As it stands it
could do with more RAM (expandable on
board); then it becomes a reasonably
useful tool to learn assembler program-
ming for the 6502.
@With the Basic, which was not tested, it
is certainly worth consideration for home
use. The cassette interface could be
improved to work with cheap recorders
and the manuals could be made more
readable, but the AIM-65 is a very
pleasant system. @
39
GEMSOFT
Programs for the PET, supplied on high quality cassettes.
We are pleased to announce our new catalogue, containing
over 50 programs, all of them available-for the PET, and some
for the Exidy Sorcerer and Apple 2. Send SAE for full catalogue.
Programs are despatched immediately, and all prices include
postage, packing and VAT (except where stated).
TEXAS TM990/189M
for only £249 + VAT
GAMES
ZAP THE KLINGONS (S) Fast moving space game with excellent
graphics £6-00
DROPOUT (S) Get the ball through the maze without hitting the sides,
good graphics. £6-00
DOMINOES (S) Our version of the game, unfortunately it has an
uncanny knack of winning. See if you can beat it. £6-00
CROSSWORDS 1-3 A real crossword puzzle on your computer.
Excellent graphics, and three programs on one cassette. £6-00
OIL RUN (S) Fire torpedo’s at the enemy tankers, dodge the mines. £4-50
ARROW (S) An intriguing and fast moving game with excellent graphics
and sound effects. £5-00
INEBRIATED BLACKJACK A very different game of blackjack, one
which will keep you amused for along time. Super graphics. £6-00
RICOCHET (S) Aim the batl around the screen, and watch it ricochet,
a real arcade game with good graphics and sound. £5-00
pate ATTACK (S) Dogfights in space, with all the drama and sound
of S**rwe't.
STAR TREK Our version of this famous game good graphics.
PETALS AROUND THE ROSE A real mystery game with a hidden
formula. Amaze your friends with your intelligence (once you learn the
secret). £4-5
SCRAMBLE Write your own funny stories with the computer. £4-50
BATTLESHIPS Destroy your opponents. and out manoeuvre him. £4-00
NICKY NACKY NOO Every library has a number of guessing games,
The new single board computer from Texas Instru-
ments. Designed as a learning aid for hands-on
experience plus instruction in microcomputer funda-
mentals.
Available from WATFORD ELECTRONICS for only
this is ours. £3-50 E 3 :
OSC LANDER Land your lunar lander on the moon surface, excellent £249 + VAT. Comes complete with a comprehensive
graphics. £6-00 ' i on R ier
Other games in preparation include Horse Race, Explore, users guide; ideal for colleges and universities hes
Bagels Xx 2, Nimete. primary course book for a 16-bit microcomputer
MUSIKAL & JIGSAWS (S) Musikal.is a continuously moving kaleide- class.
scope, with rythmic atonal music. Jigsaw reassembles letters on the ‘ :
screen withsound. £4:50 For full details contact:
CALENDAR & DATE CALCULATOR Displays 1979 calendar (can be
updated to 1980), and finds any date. £3-50
JOTTOA five letter usable word guessing game. £3-00 WATFORD ELECTRONICS
CRYPTO Helps to break down coded messages. £3-00 33/35 Cardiff Road, Watford, Herts, England.
KEYBOARD RECORD (S) Turns your pet into a musical instrument.
Stores up to 255 notes, and will.play them back at will, from the mem-
ory. (S)
TEACH YOURSELF MORSE (S) The computer generates morse letters
and you have to match them, Will also generate morse from typed in
messages. £4-50
COMPUTER ART We have a small, but growing section of pictures
printed on our Teletype 43. Programs are available for: Nude Lady,
Miss Santa, Love, Poster and Calendar. Prices from £2°50 to £4:00. Send
for catalogue.
Educational & Scientific Programs
METRIC TABLES Converts Temperature, Weight Area, Volume, to and
from metric.
CURFIT Fits 6 different types of curves to your data.
TRIANGLE Solves triangles.
DISTANCE CALCULATOR Calculates distances between two points
from latitutde and longitude.
FACTOR FINDER Breaks down integers into prime factors. £3-00
MARKS Grades students exam results, stores data on tape for update and
future reference
Allthe above s & e programs are £4 unless stated.
BUSINESS PROGRAMS
We specialise in writing business programs for the Pet com-
plete with twin floppy disks and large memories. Please
contact us for complete hardware and software packages
based on the Pet. Programs available and in preparation
include Accountancy, Stock control, VAT, Mail lists etc. The
programs below, willallrun onan 8K Pet.
Mail Order, Callers welcome. Tel: Watford 40588/9.
@ Circle No. 157
PAXTON
COMPUTERS
LTD
Computer Systems Specialists
EQUINOX 300
NORTH STAR HORIZON
MORTGAGE Calculates monthly repayments etc. £4-00
PORTFOLIO Keeps a file of stocks and shares on tape, calculates buying,
selling, evaluation eic. £600
GENPACKS 1-4 A package of four programs on individual cassettes,
with full documentation, designed for the small businessman. Together
they calculate the VAT, and store results on files, a customer Jist, cash-
flow, debtor/creditor list, and other statistical information. £55 for 4
programs, or £15 each.
PROGRAMMING AIDS
LINE RENUMBER A new basic/hex subroutine for re-numbering a
program inincrements of 10. £6-00
HEXCONV Converts dec to hex and vice versa. Examines single bytes in
Hex, decimal, ASCII, and binary. Conversion chart supplied with pro-
@ Computer Systems Design
@ Computer Systems Software
gram. £1000
TRACE Shows program working line by line in slow motion. The lines
are displayed on the screen in reverse field. £8-00 PAXTO N co M PUTE RS LTD
GSI SOUND BOX The suffix (S) after a program name denotes that
the program has sound effects built into it, and these can be utilised to
the full with the GS1 Sound Box. This well designed speaker/amplifier
plugs into the user port. It is battery operated (not supplied) and costs
£15-50 direct from us (post 50p), or your nearest Gemsoft dealer,
TRADE ENQUIRIES WELCOME
COMPLETE BUSINESS SYSTEMS AND PACKAGES DESIGN-
ED TO ORDER. SOFTWARE AND HARDWARE SALES.
DUPLICATION OF COMPUTER PROGRAMS IN LARGE
QUANTITIES. MICRO SOFTWARE CONSULTANCY SERVICE.
See us at our stand at the 1979 Micro-Computer Exhibition at The
Bloomsbury Centre Hotel, July 5-7.
GEMSOFT:- "Alverstone Lodge’, Wych Hill Lane, Woking,
Surrey (04862) 60268
Foose esse [nfo on] Yoffa Yoni] of os] info] [no fu] ef o|eaoce =
@ Circle No. 156 @ Circle No. 158
PRACTICAL COMPUTING July 1979
26 High Street, Great Paxton,
Cambridgeshire
Tel. Huntingdon (0480) 213785.
BEDS - CAMBS - HERTS
NORTHANTS
L
o
Sol Terminal Computer
|
Robust SOL-20 becomes
competitive for the
small business user
THE SOL-20 terminal computer is manu-
factured by Processor Technology Corpo-
ration of California and has been around
for some three years. In the U.K. it is
tributors include The Byte Shop, which
loaned us the review system.
The system is built around an Intel
8080 microprocessor, with up to 64K
‘bytes of user RAM, 1KB of system
|scratchpad RAM, another 1KB RAM for
the display, and 2K bytes of ROM used
for what Processor Technology calls a
‘personality module’, or monitor.
Personality module
The: personality module supplied with
our SOL was the SOLUS operating
system. It allows the use of a bootstrap
disc loader and can run SOL as a stand-
alone system. Also available are a
cassette-based version and a third alter-
native for user-programmed ROM appli-
cations.
The SOL resembles an enlarged key-
board unit, minus the display but pro-
PRACTICAL COMPUTING July 1979
available from Comart, whose nine dis- |
puter
vided with wooden side panels — they
look not unlike teak. The keyboard is a
standard QWERTY layout with a sepa-
rate numeric pad. Built into the side
panels are two carrying handles but the
by Jim Wood
unit is still fairly bulky; it is large enough
for a display monitor to stand on and it
contains a large power supply and a fan.
Interfaces are provided for video
output, dual audio cassettes, an eight-bit
parallel 1/0 port, and an RS-232 serial
interface. Both parallel and serial ports
are 25-pin D-type sockets, the parallel
one male and the serial female. All are
located at the rear of the unit, easily
accessible and marked clearly.
The back of the cabinet also contains a
commendably large on/off switch, the
small but clearly adequate fan, a power
plug socket —- it certainly helped being
able to unplug the lead at both ends when
moving the SOL - and a socket for the
video monitor.
Keyboard
Despite the general air of substance
and size of the SOL, the keyboard is a
| little cramped in its layout. The space bar
| iS not separated but has cursor control
| keys on either side. The RETURN key is
about half the normal size one would
expect; it, too, is unfortunately sur-|
rounded by keys. It does not protrude
enough and it is placed next to the @ key.
In the SOLBasic this key has the effect of
scratching the line being entered. Hitting
it accidentally instead of RETURN hap-
pens far too often.
To balance those criticisms there are
many good points about the keyboard.
For instance, three colours are used to
distinguish between the normal al-
phanumeric keys, the controls, and spe-
cial keys. The keys to switch on-line/
local, upper/lower-case and shift lock
each have a small red light which shows
when the key is depressed and locked.
(continued on next page)
4)
(continued from previous page)
This is particularly helpful; so is the
provision of a separate upper/lower-case
key instead of having to use the more
common shift operation.
Easy access
Including upper- and lower-case, the
keyboard offers 85 standard characters.
By the use of the control key, a further 36
Pet-style graphics characters are avail-
able.
The cover of the SOL is easy to
remove. You slacken two butterfly nuts
at the rear and lift the two dove-tailed
sections clear. The S-100 bus and the
plug-in printed circuit boards are simple
to reach; the 22 internal control switches
are within the reach of a not over-long
fingernail. These switches determine the
mode of operation, allowing changes to
baud rate, display of control characters,
solid or blinking cursor, and normal or
inverse video.
Display
The monitor provided by Byte Shop
with our SOL was a Sanyo Super 12
portable monochrome TV. It proved to
be a rather cheap attachment to a system
which otherwise qualifies as more expen-
sive than most. The connectors bene-
fitted frequently from judicious wiggling
to find the best quality of display.
The characters are reasonably large,
the level of contrast defining the clarity,
but they tended to run into each other.
{'
ai Jerminal Gomputer
iGo er
ina
Sol Terminal Computer
TENN
The cursor may be selected as solid or
blinking; and the inverse video certainly
worked, though with the right-hand side
of the characters tending to drift back to
normal video.
Fourteen lines of 62 characters are
allowed on the monitor. Lower-case
characters have true descenders and
there is a rub-out key to remove charac-
ters from the screen. A cover is also
supplied to keep dust from the screen.
Manuals
The documentation supplied with the
system was extensive and of high quality.
The most important item was the Systems
Manual. It contains easy-to-follow and
well-structured sections covering almost
everything the SOL user would require to
know about the computer.
There is information on construction,
hardware set-up, peripheral connections,
wiring diagrams, hardware and softwaré,
definitions and explanations — even an
introductory letter to the (American)
SOL users’ society. The style is easy to
follow and in general the contents are
concise and to the point.
The manual we were given for the
Basic was the Users’ Guide to North Star
Basic - SOLBasic is almost exactly the
same as North Star Basic. It is sold
separately and we are reviewing it sepa-
rately. SOL is not the only computer
which can attach North Star discs but the
initial impression is that this is a well-
written guide to a disc-based Basic.
Prices
These prices were quoted by the Byte
Shop, which supplied the test system.
All prices are exclusive of VAT.
Hardware
SOL with 16KB £1,785
SOL with 32KB £2,060
SOL with 64KB £2,610
12in. display monitor included in basic
price ‘
| North Star mini-floppy drive £635
(80 or 160KB)
Dual drives £1,060
Hyterm 1610 printer £2,220
Hyterm 1620 keyboard/printer £2,400
Centronics printers £950 upwards
Software
SOL disc Basic
Included in the basic price
CP/M disc Basic £150
Disc
Word Processor (Electronic Pencil} £135
APL Not quoted .
Cassette
Extended cassette Basic ' £35
Basic 5 £20
Focal £25
ALS-8 (Assembly language) Not quoted
—
More systems
A number of cassettes and manuals for
FOCAL, Extended Cassette Basic and
Basic 5 were provided. We could not
attach a cassette recorder — we didn’t
have the proper leads — but we intend to
review them at a later date. A cassette-
based assembly language, ALS-8, is also
available.
Two further disc-based systems are |
available — CP/M disc BASIC and a |
version of APL; we had neither for |
review but any readers with opinions on
them are invited to send us acritique. |
A single North Star mini-floppy disc |
drive and a Diablo printer were also
supplied with our system. That occasions
further criticisms. The on/off switch on
the disc drive is not labelled and caused
some confusion when switching-on; and
we were unable to deduce how to send
something to a printer from a SOLBasic
program — the Users’ Guide makes no
mention of external printing.
Plus points
Points we liked about the Basic, a 16K
version, were:
@ string arrays with substrings.
® support for both sequential and random
files.
@ multiple statement lines.
@ string length restricted only by the
available memory size. |
@ a reasonable line editor, based on the
use of control keys. |
@ a line number range up to 65535, with |
automatic line numbering available
along with a simple re-numbering
facility.
The Basic is straightforward to use and
is definitely helped by the Users’ Guide,
which takes a humane step-by-step ap-
PRACTICAL:COMPUTING July 1979
proach to mastering the system, but we
have some criticisms:
@ there is no PRINT USING statement.
@ lack of printer addressing.
@ not all errors are notified to the user —
using a string variable with a length
greater than that defined wiil cause the
disappearance of the extra offending
characters.
@ Accuracy is limited to eight digits, al-
though the range for a variable is +10®,
One pressing criticism of the Basic is
that it is fairly slow. A standard simple
benchmark, the loop FOR 1=1 TO 1000/
NEXT 1, takes 2.4 seconds; that is about
the same as our Tandy TRS-80 and seems
on the slow side for a considerably more
expensive system.
Expansion
A less important and less annoying
attribute is the necessity to drop into the
operating system to create disc files; you
cannot do this from Basic.
The SOL scores well when expansion is
considered. Memory may be grown to
64KB — our system had 32KB — and up to
four mini-floppy disc drives and two
cassette units may be attached. As the
system utilises. the S-100 bus, there are
several compatible devices which can be
used. The basic system contains space for
five expansion modules.
RS
Conclusions
@ SOL is well made and seems robust. The quiet back fan keeps it cool and
there is much to be said for using standard technology (S-100 bus). There is a
wide range of software, both cassette and disc-based. The ‘personality module’
is another plus.
@ For an expensive personal computer system — £2,700 plus for the basic
32KB configuration and disc drive — the standard of monitor we tested is
rather poor. That could easily be altered, of course.
@ More important, the keyboard could certainly benefit from a redesign of
the layout.
| @ Standard basic is easy to use, though we bemoan the lack of PRINT USING
and an easy access to the printer. The User Guide we saw is good and in general
the standard of the Processor Technology documentation is excellent, both for
a reference user and the beginner.
@ At the price, the SOL is moving out of the personal computer market and
so must be aimed at the small commercial business user. There its price begins
to appear reasonably competitive. In this context, being able to have four disc
drives on-line is an advantage and while the Byte Shop doesn’t offer 8in. |
floppies, soméone else must do so.
@ Even so, the SOL works with dual-density mini-floppies and so can access a
minimum of 640,000 bytes of storage.
Practical Computing evaluation
Yes/No 1 2 3 4 §& ves/Now.§ 2..3 4 §
NA N/A
Ease of construction (where NA Assembly language v
applicable) wa Basic language v
Quality of documentation v Other languages Y
Dealer support/maintenance v Compatiblity with other
Can handle 32K of memory Y systems : | J
Quality of video monitor Reputation of manufacturer v
(consider resolution and A Y
- screen size) v le de ean
a as y
SS-50 Bus N eer hs
aaa No. of software applications
a v packages available J
Sockets for chips N Hobby use &
Numeric, calculator-type . ¥
pad on keyboard Y Business use ’
Large amount of removable Sducwionaliave
memory, randomly accessible Y Suitability for: 4
i
Cedestte tape recorder Commercial applications
capability: Own Home applications 3 v
Built-in recorder N Educational applications v
Floppy disc capability Ability to add printer(s) Y
Communications capability Ability to add discs Y
(can talk to other computers} Y Ability to add other
Speed of instruction cycle 2mHz manufacturers’ plug-in memory v
Ease of expansion v Ratings
Lower power consumption ‘, 1 = poor; 2 = fair; 3 = average; 4 = good; 5 = excellent. N/A =
PRACTICAL COMPUTING July 1979
not applicable.
43
HAVING carefully studied and, it is
: hoped, understood the requirements of
the system being designed, the next step
is to decide whether it is worthwhile
maintaining a file for each type of
information. If so, then we must also
decide on the most suitable method of file
| ‘organisation to use.
In small business systems the two
files found most commonly are the
product or item file and the customer file.
The former will hold all the details of
each item stocked or sold — part number,
description, price, quantity in stock — and
the latter the details of each of the
customers or potential customers — ad-
dress, terms of business.
Other files often will be necessary but
all my comments relating to those two
can be applied to any file of data.
For an order entry and invoicing
system both a product file and a customer
file may be needed but, we must not
assume automatically that they must
exist. A mail order company may have
many customers, each one ordering once.
only with a very low likelihood of repeat
business, so in that instance it would be
better not to have a customer file but to
type-in the customer details with each
order.
Besides, it is unlikely that a small,
floppy disc-based computer could handle
the large volume of data required to
create such a customer file — a reasonable
size of file to consider handling would
have a few hundred customer records.
rather than a few thousand.
Two approaches
Similarily, a business dealing in special-
ised, custom-designed products may well
not justify the creation and maintenance
of a product file.
purposes of this article it is assumed that
both a customer file and a product file are
needed and that, in addition, each
transaction will be recorded for subse-
quent processing to produce accounting
information.
On most small computers with floppy
disc of one form or another there will be
two possible approaches — sequential or
direct files. The choice between them
usually will be clear since sequential files,
as the name implies, can be written to or
read from only by starting at the first
record on the file and then progressing to
the next and so on.
This is obviously useless if we want
rapid access to a particular record — even
10 seconds is a long time to wait when
you are sitting in front of a computer
terminal with fingers poised for the next
entry.
If several hundred records have to be
read before the correct one is found the
delay could be an order of magnitude
greater. Our transaction file would fit
well on to a sequential file, though; it will
be processed by the accounting program
44
Anyway, for the.
How to
decide o
file organisation
only in the same order in which it was
written, so there will be no problem in
finding records.
Both customer and product files need
to be organised so that any record can be
found with minimum delay. Direct files
allow this and are simple in concept; the
problems lie in the ways in which direct
files can be used.
Stated simply, a direct file access
method requires to be given a record
number and will return with the contents
of that record. The format of the Basic
statement to do this will differ from
machine but will probably be of the
following form:
GET N,R,A£ to read from the file
PUT N,R,A£ to write to the file
where N is the file number and R is the record number
and the contents of the string variable AZ are either read
from or written to the record.
Mike Collier’s introduction to
computer user in business now
systems analysis for the small
looks at records and files.
each key table entry will be nine charac-
ters, and 14 pairs can be stored on a 128-
byte record. The entire key table for a file
of 280 products will thus occupy 20
records. To find any record will require
an average of 10 GETs to find the correct
key table entry and one more to read the
record from the data file. That is almost
the maximum number of GETs which can
be tolerated, so for larger files another
approach has to be found. For small files
this approach is simple to use and simple
to program and does not require any
sorting of the data file or the key table.
Larger files require a more complex
method to keep down response times. If
sufficient memory is available the key
table could be resident (i.e. in memory).
It is important, however, that whenever a
new record is inserted, the revised key
The required record can thus be found
given its record number, but this is not a
complete solution — the record number
still has to be found. The user of the
system cannot be expected to know the
record number of each part or customer
and to enter it each time access to a direct
file is required.
As you will have read in last month’s
article, it is unrealistic to expect the
person entering data to know any more
than the part number or customer code to
which he has always been accustomed.
What has to be devised is some way of
converting, within the computer, the part
number into a record number on the
product file and the customer code into a
record number on the customer file.
There are several possible approaches
to performing this conversion, which to
choose depends on the circumstances and
the size of the file. For reasonably small
files — 200 to 300 records — perhaps the
best approach is to maintain a ‘key table’.
That is a list of the cross-references
between the ‘key’ — the part number or
customer code — of each record and the
record number at which the associated
information is stored.
Key table
The ‘key table’ can be stored on disc
either as a separate file or as part of the
main data file to which it refers — see
“record types” in the next instalment. If
each part number is six characters long
and the record number three characters,
table should be written on to the disc file;
otherwise the location of the added
record could be lost in the event of any
form of program or mains power failure.
If the simple approach cannot cope
with the volume, or if very fast file access
times are necessary, there are ways of
sophisticating the method. For example,
the key table could be held sorted. That
would allow a form of binary search to be |
used on the key table records — i.e., read
the middle record, if the required key is
below then read the middle record of the
lower half, and so on.
Alternative
Alternatively an index of the key table
records could be maintained in memory,
holding the first key on each key table
record. With this method only two GETs
will be necessary, one to find the key
table record and one to find the record on
the data file.
To pay for this efficiency it will be
necessary to insert new keys into the
table in the correct sequence and re-write
any key table records affected by the
change — figure 1 illustrates this method.
There is clearly more effort required of
the programmer to achieve an efficient
technique for reading and writing direct
files. In fact, the ultimate extension of the
key table approach is sometimes avail-
able as proprietary software and is called
Indexed Sequential file access — this is the
method often used on large computers.
One matter to be resolved is how to
PRACTICAL COMPUTING July 1979
1 suitable
method
delete records no longer required. It
would take too long to shuffle all the
records following the deleted one to fill
the vacant space while the user is sitting
waiting at the computer. It is much easier
and quicker to allocate a particular field
on each record which can contain a
deletion marker.
To delete a record, all that is necessary
is to enter a defined value into this field.
A special program can then be written to
go through the whole file sequentially,
dispensing with all records flagged for
deletion, printing them out for archiving |
and shuffling subsequent records to fill
the spaces left.
This program would also re-create the
key table records and would serve the
additional purpose of being able to re-
constitute the key table should any error
in processing or in the disc drive cause
corruption of the file.
A different approach which avoids any
need for a key table is that of using a
Randomising Algorithm. This
complicated-sounding title means using
some mathematical rule to convert the
key into a record number, Let us consider
the requirements of such a rule:
@ Application of the rule to any
particular key must always yield
the same record number.
@ Even though the distribution of
values for the keys may not be even |
over the range of possible values,
the record numbers must be spread
evenly throughout the file to
minimise space on the disc.
@ Ideally, no two keys should yield
the same record number; this is
virtually impossible to achieve and
there are ways to circumvent it but
the possibility of such occurrences
should at least be minimised.
Fastest method
The procedure to be described may |
appear somewhat complex but it can be
programmed in only a few lines and is
often the fastest method of finding the
required record.
The first step is to convert the (prob-
ably) alphanumeric key into a pure
numerical value. There are many ways of
doing this and the method described here
is not necessarily the best but it works
and it is simple.
Each character of the key is taken in
turn and its ASCII value found; the total
of all these ASCII values is then the
numeric value sought.
PRACTICAL COMPUTING July 1979
Pathan
FOR [=1 TOL
T=T+ASC(MIDE(KEYE,1,1))
NEXT 1
This routine will, of course, produce
the same value of T for two keys which
have the same characters but in a
different sequence. To improve matters,
line 40 could be cha to:
40 T=T+I*ASC(MID£(KEY£,I,1))
thus giving different weightings to each
character of the key.
Having derived a numeric value it must
be modified if it is to become a valid
record number which is equally likely to
be any value between 1 and the number
of records in the file. The ‘equally likely’
part is to ensure that the whole file space
is used rather than having the first half
full and the last half empty, since it will
become clear that the efficiency of this
technique depends on there being only a |
small probability of more than one key
giving the same record number.
The best way to achieve this is to
ensure that the whole file space is used.
The RND function will give a random
value which can be modified easily to give
a random value between 1 and N and,
what is more, it does so in a predictable
way.
Repeatable
Different Basic interpreters have diffe-
rent ways of using the RND function, but
most require that it be given a starting
value from which to generate its stream
of pseudo-random numbers. By using the
value of T as obtained for the starting
value, the number produced by
RND will have the required attributes of
being repeatable and of being equally
Key Table Index:
containing the first Key
on each record of the Key
Table (held in memory).
KEYB|RN2|KEYC|RN3|KEYDIRNG| etc
KEYH|RNS| etc|..
Fig. 1 Illustrating the method of using a
Key Table together with Key Table Index to
find the data relating to KEYD
likely to be anywhere within the pre-
scribed range. Thus:
60 X=RND(-T)
70 X=RND(T)*NREC+1
(Microsoft BASIC on the SORCERER)
NREC is the number of records on the file.
On any other machine the statements
may be different but the Sorcerer initial-
ises the random number stream by calling
RND with a negative argument.
X is then the record number where we
would like to store this particular item of
data. It has been found with only six lines
of program and without the need to read
disc files. There is, however, one further
step which’ must be carried-out before
storing the data there. It is possible that
some other key has been entered previ-
ously which happened to generate the
same record number, so it is necessary to
check that the record is not already
occupied.
That could be a simple test that the key
field on the record is equal to all blanks —
any other value signifying that the record
has been used previously. If it has, there
is no problem; try the next record on the
file, and so on, until a vacant one is
found.
To retrieve a record, exactly the same |
calculations are performed and when the
record number is found the key field is
tested to see if it is the one required. If
not, the next record is checked, and so
on, until the correct key is found or a key
of all blanks is found — signifying an
unoccupied record.
In the latter case it is clear that the
requested key cannot be on file, since if it
was it would have been stored in that
vacant slot.
To find the record in which to store a
new item, the following program can be
used:
80
90
100
110
120
130
GET N.X,A£
IF LEFT£(A£,6)= ~
X=X+I
IF X>NREC THEN X=1
GOTO 90
REM VACANT RECORD FOUND (=X)
* THEN 130
and to read the file to find the record with the key
of KEY :
80 GET N,X,A£
90 + IF LEFT£&(A£,6)=KEY£ THEN 150
100 IF LEFT&(A£,6)= °° THEN 1000
110 X=X+1
120 IF X>NREC THEN X=1
130 GOTO 90
150 REM FOUND THE RECORD
1000 REM NOT ON FILE
The great advantage of this method is
that neither key table nor file look-ups |.
are needed. Most accesses will need only |
one file read, provided a reasonable
amount of slack has been allowed in
setting-up the file size.
Twenty percent would be a reasonable |
figure so that if 1,000 records is estimated
as the maximum to be stored, the file
should be given 1,200. As the file fills the
number of reads will increase, so it may
be necessary to write a program to extend
the file.
That program will restore every record
in a new record number since the
algorithm with the new value of NREC
will give new record numbers for each
key.
I hope this rather technical chapter has
not deterred you — it sounds more
. difficult than it really is. Next time I will
be looking at the various items of data
which can be held on files and at the
relevant items of hardware and software
which can affect small business systems. &
ees Designing for small business aaa
45
THE EXPANDABLE GENERAL-PURPOSE MICROCOMPUTER
DAMPING FACTOR:> 4€-04
>
>>>> THE 300Z a&8a HAS GRAPMECS >??
oe Con use them for simulatioes””
ee
MACHINES SOUZ
THE RESEARCH MACHINES 3802
A UNIQUE TOOL FOR RESEARCH AND EDUCATION
Microcomputers are extremely good value. The outright purchase
price of a 380Z installation with dual mini floppy disk drives, digital
1/0 and a real-time clock, is about the same as the annual mainten-
ance cost of a typical laboratory minicomputer. It is worth thinking
about!
The RESEARCH MACHINES 380Z is an excellent microcomputer for
on-line data logging and control. In university departments in
general, it is also a very attractive alternative to a central main-
frame. Having your own 380Z means an end to fighting the central
operating system, immediate feedback of program bugs, no more
queueing and a virtually unlimited computing budget. You can
program in interactive BASIC or run very large programs using
our unique Text Editor with a 380Z FORTRAN Compiler. If- you
already have a minicomputer, you can use your 380Z with a floppy
disk system for data capture.
What about Schools and Colleges? You can purchase a 380Z for your
Computer Science or Computer Studies department at about the
same cost as a terminal. A 380Z has a performance equal to many
minicomputers and is ideal for teaching BASIC and Cesil. For A
Level machine language instruction, the 380Z has the best software
front panel of any computer. This enables a teacher to single-step
through programs and observe the effects on registers and memory,
using a single keystroke.
WHAT OTHER FEATURES SET THE 380Z APART?
The 380Z with its professional keyboard is robust, hardwearing
equipment that will endure continual handling for years. It has an in-
tegral VDU interface—just plug a black and white television into the
system in order to provide a display unit—you do not need to buy
a separate terminal. The integral VDU interface gives you upper and
lower case characters and low resolution graphics. Text and graphics
can be mixed anywhere on the screen. The 380Z also has an integral
cassette interface, software and hardware, which uses named cassette
46
files for both program and data storage. This means that it is easy
to store more than one program per cassette.
Owners of a 380Z microcomputer can upgrade their system to
include floppy (standard or mini) disk storage and take full advantage
of a unique occurrence in the history of computing—the CP/MTM*
industry standard disk operating system. The 380Z uses an 8080
family microprocessor—the Z80—and this has enabled us to use
CP/M. This means that the 380Z user has access to a growing body of
CP/M base-software, supplied from many independent sources.
380Z mini floppy disk systems are available with the drives mounted
in the computer case itself, presenting a compact and tidy installa-
tion. The FDS-2 standard floppy disk system uses double-sided disk
drives, providing | Megabyte of on-line storage.
Versions of BASIC are available with the 380Z which automatically
provide controlled cassette data files, allow programs to be loaded
from paper tape, mark sense card readers or from a mainframe. A
disk BASIC is also available with serial and random access to disk files.
Most BASICs are available in erasable ROM which will allow for
periodic updating.
If you already have a teletype, the 380Z can use this for hard copy or
for paper tape input. Alternatively, you can purchase a low cost
380Z compatible printer for under £300, or choose from a range of
higher performance printers.
*CP/MT™ Registered trademark Digital Research,
380Z/16K System with Keyboard £965.00
380Z/56K complete with DUAL FULL FLOPPY DISK SYSTEM
FDS-2 £3,266.00
380Z Computer Systems are distributed by RESEARCH MACHINES,
P.O. Box 75, Chapel Street, Oxford. Telephone: OXFORD (0865)
49792. Please send for the 380Z information Leaflet. Prices do not
include VAT @ 8% or Carriage
@ Circle No. 159
PRACTICAL COMPUTING July 1979
ne enemes V'00 0066 SS i115 =
Something for everyone
LAST MONTH we surveyed what you can and cannot expect from word processing on a
microcomputer. Part two of our review looks at some of the specific products offered for the micro.
Some are off-the-shelf applications packages; some are software systems from the hardware vendor.
The price range is from £15 for a Pet cassette to more than £300 for a fully-fledged disc word
processor. There must be something here for everyone.
Apple II: Word Processor
Cassette systems. Available from Keen
Computers. Price: £50.
KEEN COMPUTERS, one of the more
active U.K. dealers with the Apple I], is
at pains to point out the limitations of this
package. For a start, it is intended for
writing standard letters — they are typed-
in, stored on tape, recalled and amended
as required, with new lines and variable
information added to personalise them,
and then printed. |
Commands include insert, delete and
change lines; search and replace for
specified strings; and line centring. You
have to specify approximately how many
lines you expect to enter before you start
keying, and specific omissions include
insert and delete for individual words,
left and right justification, and document
assembly from standard assembly.
Keen says they will all be featured ina
Mark II version which should be avail-
able towards the end of the year.
Commodore Pet: MEDIT
Cassette system. Available from Petsoft.
Price: £15,
THIS alternative to the CMC word
processor in the Petsoft catalogue also
has a very good user manual. The
introduction makes no bones about the
matter: ‘““MEDIT is a very simple and
basic editor, designed to run on an 8K Pet
with a single cassette”. Editing data
requires plenty of time and much juggling
of cassettes.
MEDIT leaves about 3K in a small Pet
and to allow for merging and inserts your
cassette files must be less than 1,500
bytes.
You have a total of 18 commands,
including those to open and close files.
You can read in and store specified
members of: lines and part of a line,
inserting and deleting simply as required.
There are no print format facilities and
no search and replace functions,
Commodore Pet: CMC
Word Processor
Cassette system. Available in the U.K.
from Petsoft at £25; also available through
Kingston Computers.
CMC in this context is a software house
called Connecticut Micro Computer and
though this package saw the light of day
only this year it already has acquired a
good reputation. For a start it has very
good documentation considering it is a
low-cost cassette.
You can delete and insert lines, edit
within a line, replace one line with
another, and move text blocks around.
PRACTICAL COMPUTING July 1979
There is no automatic search and replace
facility, though. Files may be saved and
merged; the left margin can be adjusted
for indentation but there is no right-
justification. Other print directives set
the line length and spacing, and centre
headings.
CMC wrote the system for an 8K Pet
but that leaves space for only 2,000
characters of text —- about 100 lines. You
will have to print or save one section
before starting another. You might find
extra memory handy, and a better key-
board is almost essential.
Petsoft has a version for RS232 printers
and direct connections to the IEEE port,
We are told a floppy disc version is on the
way — price about £30.
Commodore Pet: Word
Processor
Cassette system. Available from Costed
Automation. Price: £125 (plus software
support contract at £125).
THIS is not a load-and-go word processor
like most Pet software. Costed says it will
have to be “installed” by its own staff,
who will also modify print output para-
meters — such as line length — to suit the
printer you have, The price includes
training for one person.
Training is essential, because there. is
no manual for the system. Costed de-
clares that it is “very easy to understand
and use”’ but it “becomes.cloudy if on-site
training is not given’’.
The command includes text entry;
listing, deletion, inserts and amendment,
and saving on to and reading from
cassette — there is no disc version. Output
formatting commands allow you to define
new paragraph, new line, tab positions,
and standard parameters for characters
per line, line spacing, lines per page, and
the position of the left-hand margin. Text
can be centred, and indented. |
There appears to be no search facility
and no right-hand margin functions, like
justification and coping with widow lines.
The only printers acceptable are those
which connect to the Pet IEEE interface.
Compucorp 600: TEXT/
ONE
Disc system. Available from Compucorp
and its distributors. Price: £1,000.
THE Compucorp 600 is a family of desk-
top computers starting at about £4,500.
The systems combine screen, keyboard
and floppy discs in one unit with a printer
separate.
TEXT/ONE promises to be “more
comprehensive in operation yet sinipler
to operate than systems costing much
more and accomplishing much _less’’.
Functions include addition or deletion of
characters, words or lines: block move-
ment of paragraphs, pages and other
sections of text; and document assembly
from standard paragraphs.
The search-and-replace facility is good
and there is a useful mailing list capability
which is rare On microcomputers — with it
you can insert variable information in
standard letters automatically, and the
system can select exactly which choice of
several options will go in as the variable.
text.
A significant aspect of this system is the
use of single keystrokes for WP func-
tions; there are about 60 of them. The
Compucorp 600 has a row of special keys
on the keyboard, the functions varying
according to what software is running
word processing operations. Compucorp
provides a strip of key labels to tell you
what the keys mean. ;
CP/M systems:
WORD-MASTER
Disc system. Available from several U.K.
sources. Price: about £95.
CP/M is a popular operating system now
available as standard or an option on
many personal computers. Those we
know of include Rair Black Box, Exidy
Sorcerer, TEI, Cromemco (CDOS is a
variant), North Star Horizon, Pertec
PCC 2000: and Compelec Series/1, and
the Computer Centre disc systems.
Compelec, incidentally, sells WORD-
MASTER integrated with the MicroPro
‘mailing list system on both its computers
(2000 and Series/1) for £250.
MicroPro is the Californian software
house which developed WORD-
MASTER. It has a full set of edit
commands you can move the cursor left
or right by one character, which is normal,
or by one word, which is most unusual;
you can go to either end of the line or the
screen, and you can move the whole file
up or down on the screen. Lines, words
and characters can be inserted or deleted
left or right.
The command mode is equally impres-
sive; it provides for manipulation of
stored text. It gives a good variety of
search-and-replace options, including a
loop facility, so that after a search failure
the program can go for some alternative
search parameters.
WORD-MASTER has some fairly
powerful file management facilities, too;
automatic back-up and re-start — the
original file is preserved; automatic
paging and buffering — to manage the
transfer of information between disc and
memory; copying and saving any or all of
specific text files as required; retrieval
(continued on page 49)
47
All Systems Are Not
Created Equal
.
wie
Your computer application is unique. It
differs from ail others. It is because not all
applications are equal that MSI has de-
veloped a variety of computer systems.
At the heart of every MSI System is the
powerful MS! 6800 Computer, one of the
fastest and most versatile available. De-
pending on the System you select, the MS{
6800 has from 16K to 56K of RAM. Mass
memory storage in MSI Systems range from
315K bytes in the System 1 to over 10
megabytes in our most powerful System 12.
In addition to the computer and memory
subsystem, MSI Systems include a CRT
terminal and high speed character printer.
The System 12 is housed in a compact desk
unit.
@ Circle No. 160
48
A ow he Pe
- 2 se 1
“eb Saal te . ni | |
> 'y a tne
ys f
‘
wet Berm fee ee
0 ia LI
‘
As with hardware, computer software is
not always created equal. Since there are a
myriad of programs available, MSI offers a
choice of Operating Systems for use with
your MSI Computer System. Of course, our
favorite is MSIDOS, but we offer the
powerful SDOS operating system as well.
All MS! Systems will support the other
software products associated with each
operating system.
MSI also has a variety of software
programs including a complete Accounting
Package and a Multi-User Basic program
capable of supporting up to four users.
MSI Systems are currently being used in
a broad spectrum of personal, scientific,
educational, professional and business
ee Re a
OHI VON
are
PR enema cotinine sane at ve creme nnenteme
z i
| i ). one 8 i
Le
Na tn
wee ee ere
re |
at
situations. In addition to our Systems, we
can supply you with individual components
for personal and OEM use. All MS! System
components are available, some in kit form.
Write or call us for more information
about MS! Systems and products and the
name of your nearest MSI dealer.
STRUMECH ENGINEERING,
ELECTRONIC DEVELOPMENTS,
PORTLAND HOUSE,
COPPER SIDE, BROWNHILLS.
(0827) 4321 TLX 335243
PRACTICAL COMPUTING July 1979
ne 60 | ||
(continued from page 47)
and merging of files or parts of files in any
sequence.
The only obvious weaknesses are in the
lack of output formatting facilities.
North Star Horizon:
AUTOSCRIBE
Disc system. Available from Equinox and
its distributors. Price: £395.
AUTOSCRIBE is from a_ respected
Arizona software house, Microsource. It
was developed originally by a lawyer and
its bias appears to be towards the creation
of documents from a library of standard
paragraphs; we have not seen a users’
manual.
It appears to require a 32K Horizon
system, storing up to 40 documents on
each diskette with an index, and allowing
up to 70 pages per document. Features
listed include automatic formatting of
upper-, lower-, right-hand and left-hand
margins; horizontal and vertical tabbing;
underlining and centring: and, of course,
a powerful search mode and ‘append’
facility for document assembly.
Imsai VDP-40: NED
Disc system. Available from Imsai dealers
(Corner Computing and Data Precision
Equipment responded to our survey).
Included in system price.
THE VDP-40 is a ‘videocomputer’ com-
bining screen, keyboard, two 345KB
floppy disc drives and microprocessor
(Intel 8080) in one package for a starting
price just below our cut-off point of
£5,000. Its operating system IMDOS is a
derivative of the popular CP/M and
includes a ‘context editor’ called NED.
It is not a ‘true’ word processor; as it
stands it lacks any real output formatting
facilities. A context editor works largely
by string searching ~ you specify the word
or name or other character string you
require — as opposed to a line editor,
where you have to specify a line number.
NED works in one of two modes,
command or video. This editor uses an
imaginary ‘character pointer’ and in
video mode it is at the same screen
location as the cursor; in command mode
you can move the pointer independently
of the cursor. It is not as complicated as it
sounds; command mode seems to be best
for editing large blocks of text; video
mode is more appropriate for. small
amendments.
Either way, the usual range of insert,
delete and erase operations are alterna-
tives for moving through a text file. String
searching and replacement is well pro-
vided for. Less usual facilities include a
‘loop’ function which repeats a sequence
‘of edit commands a specified number of
times — probably more useful for editing
programs than text.
Microstar 4S: Flexitex
Floppy disc system. Available from Micro-
solve and its distributors. Price: £300.
MICROSTAR 4S only just gets into our
survey with a 64K business computer
system plus 1.2 million characters of
floppy disc storage priced at £4,950. That
excludes VDUs and printer.
Flexitex consists of file utilities — to
SS 6 ee 6 a a“
PRACTICAL COMPUTING July 1979
create, delete, re-name, and print text
files; a text editor; and a text processor,
‘capable of numbering pages and printing
headings and footings automatically. It
can accommodate any size of paper and it -
can retrieve information to be included in
the printout from disc files or terminal
keyboard.
There is no option in the master menu
to create a new text file, because there is
no distinction to the user between editing
text which exists and which does not
exist. The user enters some text; if the
name of the text is not on the diskette,
the user will become aware of it when the
directory of the text is displayed on the
screen, and at that time the user may
enter a name for a new text file. Flexitex
will take care automatically of creating
whatever files are necessary to accom-
plish the task.
NASCOM.-1: Letter Writer
PROMS for Nascom-1 developed by ICL
Dataskil. Price: £70. ‘
AT a personal computing show last year,
Dataski! demonstrated a letter-editing
system using the Nascom-1 basic board
with no memory expansion. Apparently
this was no more than a spin-off from
“serious development work’’. Dataskil
reports considerable interest in the con-
cept of a low-cost letter editor.
The program required only some 1.5K
in EPROM, retaining 3K of the essential
parts of NASBUG monitor. About 700
bytes of RAM was used for the letter
text.
Facilities provided include cursor con-
trol insert/delete, over-write, scroll line
or screen, tabulate, write to standard
cassette to store letter and read back,
create, amend or edit letter and printout.
Processor Technology Sol:
SOL*STAR
Disc system. Available from Comart and
its distributors. Price: £85.
SOL*STAR was written by Orange
County Computer Centre for a Processor
Technology Sol-20 with the North Star
mini-floppy drive and the North Star
DOS. Comart quotes around £2,750 for a
Sol configuration on which it could be
used. There dre versions of SOL*STAR
for the Teletype 43 — a dot matrix printer
~ and the rather more expensive Diablo
daisywheel line.
There are 30 keyboard commands. The
principal ones are stored conveniently in
two ‘menu’ pages which can be called up
at any time without losing all the text you
have just typed.
Most of the commands involve holding
down the CONTROL key and typing a
letter. Functions include cursor move-
ment, control of scrolling - in both
directions — insertion and deletion of
lines, characters and blocks, search — but
not global search and replace - and tab
settings.
You can access a third menu of. ‘sub-
system commands’, and through this you
can reach disc management functions —
save, load, delete, append, list disc
contents — and print parameters. For
output you may select right-justification,
line and character spacing, line and page
length, left margin,
titling, and underlining.
RML 380Z: TXED and TEX
Disc system. Available from Research
Machines. Price: £77.50 for both.
TXED will run on a 16K 380-Z with a |
printer and a single minifloppy, but the
system really needs 32K, and a second
disc would help.
In TXED an editing ‘cursor’ moves
around the text to make changes. You
can delete and insert lines and characters,
interchange lines, and search through
text with replacement if required.
The output formatter TEX is a sepa-
Tate program. As part of the TXED edit
process, you must embed formatting |
commands in the text file you are
creating. They include centring, new |
paragraphs, insertion of blank lines,
headings, and automatic page number- |
ing. You can specify margins — left and
right — and page and line length. Running |
the TEX program against your print file |
then produces the printed version.
TEI Systems: EDIT
Dise system. Available from Abacus.
Price: £100.
ABACUS is the U.K. distributor for the
£4,000-plus TEI videocomputer. Its ‘dy-
namic screen editor’ approaches the
specification of a genuine word proces-
sing package, and we are told it is shortly
to be upgraded.
The edit mode generally uses CON-
TROL and single character keys for its
functions. They include cursor and page
movements — the cursor can tab, pages
move 24 lines at a time — limited insert
and delete facilities and a powerful search
and replace capability.
File handling commands allow you to
load a specific amount of text, compress
blanks ~ to maximise disc space — and
display carriage returns — so-that you can
see where they will fall. There are no
facilities for automatic assembly of a new
document from existing text and there
are very few print-formatting facilities.
Tandy TRS-80 and CP/M
systems: The Electric
Pencil
Cassette or disc. Several suppliers.
THE ELECTRIC PENCIL is another of
the 1978 success stories in personal
computing. Californian Michael Shrayer
wrote it originally for micros with the CP/
M operating system. CPOM runs on most
8080 and Z-80 systems and it has also
served as the basis for the operating
systems On many other microcomputers —
Imsai, ADDS, Cromemco and others.
Electric Pencil can be used in one form or
another on a number of personal compu-
ters.
To this list the Tandy TRS-80 was
added recently, the first non-CP/M im-
plementation Shrayer has done. You
could try Rostronics (01-870 4805), T V
Johnson (0276 62506) or Optronics (01-
892 8455).
For the CP/M version, U.K. sources of
which we know include Digitus (01-636
0105), Byte Shop (01-554 2177) and
(continued on next page)
numbering and
49
| (continued from previous page)
Computer Workshop in Manchester
(061-832 2269). The price for this diskette
system seems to be £250-£300.
Even in the minimal TRS-80 version,
Electric Pencil has 34 commands; most of
them are implemented by holding down
CONTROL and typing one other key.
The cursor can be moved around on the
screen and to the beginning or end of the
file; you can scroll backwards or forwards
through the file. The usual insert and
delete commands operate on characters,
lines and text blocks - you have to set
‘markers’ to indicate the start and end of
a block.
String searching allows you to look for
strings of up to 40 characters and, if
required, replace them. You can also set-
up a coded string search, which could be
very useful; for example, if you have a
coded name and address file you might
search for a string ‘“‘DD+ + + 8X” —- the
characters are ignored and the program
picks up any occurrence of the string with
the other characters in the position
indicated.
Print formatting includes justification,
left margin, page and line length, page
and line spacing, underlining, titling and
numbering.
Adapted to the TRS-80, Electric Pencil
loses one or two bells and whistles and
you are recommended to buy a lower-
case hardware modification — who wants
word processing in capital letters only? It
will run on a 16K Level I or II. Output is
to an RS232 printer.
The Sorcerer Computer is a completely assembled and tested
computer system ready to plug in and use The standard configura -
Tandy TRS-80: Text Editor
Cassette system. Available from A J
Harding. Price: £14-95.
NO GREAT claims would be made for
this general-purpose text editor, but it
has many features found normally only in
more expensive programs and it incorpo-
rates a ‘fix’ for the annoying keyboard
bounce problem on the TRS-80.
It is fully-compatible with the RS232
printer interface supplied by Small Sys-
tems Software, which means it will run on
most printer adapters of this type.
There is a simple set of nine commands
including clear, delete and insert (charac-
ters), print, save and load. No formatting
operations are provided.
Tandy TRS-80: WORD I
Cassette system. Available from Micro
Architect, 96 Dothan Street, Arlington,
MA 02174, U.S.A. Price: $32 (includes
postage. Order with Barclaycard/VISA
and quote your number).
THIS is a 16K Level II system which we
intend to review. It is cheaper than
Electric Pencil, the only real alternative.
WORD 1 accepts lines of text in-
terspersed with lines of format control
information and formats the text into a
displayable document. Commands per-
mits you to set page length and width,
skip lines or pages, centre text, multi-
column output, title headings. Line spac-
ing and adjusting, right-justification and
page numbering are all controlled auto-
mically.
LOOK AT THESE FEATURES mo 8%
» WORD PROCESSING, COBAL, FORTRAN re
* PLUG IN. ROM CARTRIDGES
Introducing the personal
computer you've waited for.
The Exidy Sorcerer.
SS a Ord Processins mz!
Tandy TRS-80: WORD III
Disc system. Available from Micro Ar-
chitect. Price: $39 ( Barclaycard/VISA)
THIS diskette version of WORD-I offers
all the facilities of that package, plus the
attractions of floppy disc storage for text
(fast access filing). The WORD packages
have 20 user commands, miost of which
concern text formatting on output. You
use the normal TRS-80 screen edit
functions — like the cursor controls — to
alter text.
This system apparently offers no docu-
ment assembly or seaich-and-replace
facilities. There is no limit, however, to
text size. We understand there is an all-
singing, all-dancing WORD IV on the
stocks.
Zilog microcomputers:
ZFORM
Disc system. Available from franchised
Zilog dealers. Price: £100.
ZFORM is a powerful-looking - output
formatter which operates on files pro-
duced by any of several available text
editor programs for the Z-80.
This is a good example of a text
formatter. You can specify length and
width of pages, margins and headers and |
footings — including page numbers; tabs,
indents and centring are-all available; you |
can set the spacing and specify justified or
unjustified text. Among selectable op-
tions are ribbon colour change, bolt
print, underlining and sub- and supers-
cripts. |
16x £ 7GO
B59
tion includes 63 key typewriter-styie keyboard and 16 key numeric
pad dual cassette I/O, with remote computer control at 300 and
1200 baud data rates, RS232 serial 1/0 for communication,
parallel port for direct Centromes printer attachment Z80 pro-
cessor, 4K ROM operating system, 8K Microsoft BASIC in separate
plug-in Rom Pac™ cartridge, composite video of 64 chars - 30
lines, 128 upper/lower case ASCII character set and a 128 user-
defined graphic’ symbols, up to 32K on-board RAM memory,
operators manual, BASIC programming manual and Cassette/
video cables. connection for $100 bus expansion unit giving
access to the spectrum of exciting and useful peripheral devices,
such as Floppy disk drives, voice recognition/synthesis battery
back-up board in case of power failure, additional memory boards,
E-PROM cards give you she facility to program and re-program
your own ROM memories etc etc. This is the most useable and
flexible system that’s now availabie to the home and business user
at such a low price.
» WORKS WITH. NORMAL TV
* S100 EXPANSION UNIT
» CASSETTE INTERFACE
» Z80 CPU
* 32K RAM ON BOARD
+ A REAL BUSINESS MACHINE
please make cheques and postal orders payable to JADE
phone your order quoting ACCESS or VISA number
for technical information or advice phone 0736 66565
17 Market Place, Penzance,Cornwall.
@ Circle No. 161
50 PRACTICAL COMPUTING July 1979
The Attache Business System
The only system designed and supported
exclusively for business applications
Who but Attaché can offer full supporting software
at prices you can afford?
For example—Order Entry, Stock Control £160 the lot.
Basic system: Case + CPU + Turnkey monitor board
+ 16K RAM (capable of expansion to 64K) £1,466:00
Video Board £ 271-00
16KB Static RAM £ 347-00
Printer Interface Card £ 208-00
Floppy disc system 2 x 310Kb diskettes
+ controller + box £1,701:00
Basic Interpreter £ 41-00
Attaché business systems can be obtained at the following:—
Alba Computer Supplies & Services Ltd., 8 High Street, Renfrew (see John Coleman)
Computer Hardware Ltd., 113 Clonskeagh Road, Dublin 6 (see Liam McAlasdair)
GBH Data Services Ltd., Dumfries Chambers, St. Mary’s Street, Cardiff (see Geoff Higgins)
Keen Computers, 5 The Poultry, Nottingham (see Tim Keen)
Lion House Ltd., 227 Tottenham Court Road, London (see Lawrence Sarkin)
R J Spiers, Computer Contracts, 3 Birch Court, Sprowston, Norwich (see Ray Spiers)
There are still a few more distributors left
Interested? Contact Moncoland 11/12 Pall Mall, London SW1. Tel: 839 3661
Attaché—MVore than a hobby with us.
@ Circle No. 162
PRACTICAL COMPUTING July 1979
51
Keen Computers take:y |
the Future oith ther
ox \
Ss,
Apple il 16K 985.00 Software Packages are available
Additional 16K Ram 100.00 for most business applications.
Applesoft Rom 110.00 A few are:—
RS232 Card 110.00 Word Processor, Information
Printer Card 110.00 Retrieval. Incomplete Records
Disk Drive and Controller 425.00 Accounting, Sales Ledger, Order
Disk Drive W, Ot Controller 375.00 Entry Invoicing. Management
Speech Lab 165.00 Information, and a variety of
Apple Clock 165.00 Statistical Packages, Games,
Printers from 350.00 and others.
ty,
ae
=<
Keen Computers
Sb The Poultry
Nottingham
Tel: 0602 533254
Telex 37297
A practical introduction
THERE ARE too many
about computers. Too many
people hold too many rigid and
unsubstantiated beliefs about
_ what computers are, what they
can and cannot do, how and
why they work. This introduc-
tion will change all that. For a
start, let us summarise the
| myths:
© computers can think.
© computers are large.
© computers are bureaucratic.
© computers are expensive.
O most computers are run by govern-
ment organisations.
| © most of the rest are run by large
companies.
© computers are electronic brains. ~
© computers are incomprehensible
unless you are some kind of genius.
© computers are best left to someone
else.
© computers fail all the time.
They are all fundamentally incorrect.
Computers are not necessarily like that,
though some people would like you to
think so. It’s worth looking briefly at how
the myths evolved before deciding what is
wrong with them.
The whole computer business, like
most others, is driven by technological
and economic forces. When the compo-
nents were expensive, not many people
| could afford computers but for the people |
who could bear such an outlay, there
were considerable benefits of scale, so
computers tended to be complicated,
expensive and big.
Two reasons
The other main prop of the myth is the
need for dedicated acolytes. While com-
puters were complicated, it’s true that to |
| which does not differ in kind from the
understand, organise and manipulate
their complexity a bunch of specialised
jobs had to be created. The need for
computer training and the arrival of
computer jargon both served to separate
computer people from the rest of us.
Some computers are still big and
complicated; they still require specialised
staff; they still cost a good deal of money
to buy and to run; they still operate at
unimaginably fast speeds.
That kind of computer is now in the
minority. They are bought for only two
reasons ~— to solve gigantically complex
problems or to allow a large number of
people to use a little bit of the computer,
all at the same time.
Weather forecasting or space explora-
-PRACTICAL COMPUTING = July 1979
myths |
|
tion are obvious candidates for the first
category. The second is called time-
| sharing and it is an alternative to giving
_the same number of people a small
computer of their own.
A small computer of your own is what
Practical Computing is about. That mix-
ture of technology and economics has
worked to produce a breed of computer
multi-million-dollar megaliths with their
over-qualified minions, their impene-
trable forests of new and mis-spelt words,
their general inaccessibility.
| What is a computer?
Technology has provided a cheaper
and more compact type of computer. The
economic factors dictate that more
people can afford them, more individuals
want them, more businesses need them;
so they can be produced and sold fairly
cheaply. Computers are becoming access-
ible.
A computer is a fast, rule-following
idiot machine. It is fast because it is
electronic and electrons are speedy. It
follows rules because that is all a compu-
ter does; you can alter its set of rules
more or less at will, you can add rules,
you can complicate rules. It’s an idiot
because it simply can’t think for itself —
not in terms of original, creative thought,
anyway. It follows those rules.
That applies to all computers irrespec-
tive of their size, shape, colour, capacity,
nationality or the uses to which they
might be put.
The essential element is that you
provide rules for it to follow and that you
can change them. All talk of ‘rules’ is a
little abstract, so let’s give the business a
name — programming.
A program is a set of instructions for
the computer to follow. It will try to
follow them blindly, typing errors and all.
If you change the program, or substitute
another, the fast idiot will go through the
new instructions as coldly and as logically
as before.
Remember this; the freshly-arrived
computer is blank, it has no intrinsic
purpose until you give it one, and the
(continued on next page)
53
(continued from previous page)
word computer is incorrect, a historical
accident; it doesn’t necessarily do compu-
tations at all. It’s just that the first
computers spent all their time doing
calculations — for shell trajectories and
census returns, initially.
System mix
It’s helpful to start calling the computer
a ‘system’. Most computer people do and |
for a change this is a meaningful use of a
jargon word. A system is a set of
components which can be combined to
produce effects none of the individual
pieces could manage alone.
The components of the computer
system are a mix of software — which is a
group name for all your programs — and
hardware — all the pieces you could stub
your toes on; literally, everything that is |
hard, tangible and visible.
You have to relate that to what a
computer does when it is computing.
Four things happen:
© information (or words, or data, or
instructions, or whatever) goes in; and
that is input.
© the input is decoded, acted upon,
massaged, manipulated; that is proces-
sing
it may be stored for future use; so may
whole programs and any results of
processing
alternatively, or subsequently, the
results of that processing may be
displayed, printed, or in some other
way proclaimed to the outside world,
usually you; that is called output.
A conventional computer, then, has
facilities for:
O input
© processing
© storage
© output.
What happens is that you, or someone
else, inputs a program which is stored
until it is needed. Subsequently some data
is input, the program is activated and
processes it, and the results are output.
The idiot in the middle
Obviously the piece in the middle of all
this computing will be the processing
component. It will be .no shock to
‘discover that this is called a processor — or
central processing unit, or CPU.
‘Time for technology. What happens
inside a processor is that electricity moves
down one circuit or the other. The
complexity of the alternatives — how fast
the choice can be made, how quickly the
electrons can follow the chosen route,
how small the whole thing can become, is
what distinguishes one processor from
another.
There are dozens of processors, inci-
dentally, and there are many more
products for the end-user which have
found ways of incorporating the same
processor into identifiably different com-
puter systems.
O
54
Computers are really a whole series of
electronic switches. Like any switches,
they can be ON or OFF. There isn’t any
other possibility. As it happens, there’s a
neat way of expressing this ON/OFF
business — binary numbering.
Don’t be worried by this but there are |
| many numbering systems other than the
one we use, which is called decimal, |
because it uses 10 digits. The binary
system uses only two digits, which for the
sake of argument are ‘0’ and ‘1’. If ‘0’
corresponds to ‘off? and ‘1!’ to ‘on’,
obviously you have a neat way of
representing the internal operations of
the computer.
The electronics can decode a string of |
Os and Is as a series of off/on combina-
tions and you have a way of communicat-
ing with the electronics. You can tell it
that certain types of 0/1 patterns will be
program instructions; other binary struc-
tures will be information to be processed
by programs.
Suspicious characters
It is possible to write programs which
give instructions for any computer en-
coded as 0s and 1s. Provided you and the
computer both know what the binary
sequence means, it is possible to hold any
information in this form, even alphabetic
characters.
It is extremely tedious to communicate
with the computer in this way, though,
not least because any normal person
would have to keep checking on the
binary codes for alphanumeric charac-
ters. You would go out of your mind.
So you give the computer a special
manufacturer-supplied program which
will convert a more intelligible way of
expressing information into the binary
digits a computer can use. That way you
can give the computer a number or a
letter and with a quick piece of internal
transformation it can understand what
you mean.
Most computers translate characters
according to an eight-bit code, a ‘bit’
being a binary digit. An eight-bit code
comprises a string of eight digits, each of
which can be 0 or 1. That gives a total of
| semiconductor materials
128 possible combinations, enough to
give patterns for each letter of the
alphabet, each number, and a few
punctuation marks and arithmetic sym-
bols, too.
So if you key-in a particular sequence
of characters at your computer keyboard,
it will decode them into a group of eight-
bit codes, and they are the binary
sequences it can understand.
It can hold them in its memory, too.
The storage capacity of a computer, the
amount of information it can keep in
memory, is expressed usually in charac-
ters — or bytes. A ‘byte’ is eight bits, so.
generally one byte is the equivalent of
one character.
You will also encounter ‘the cryptic
| symbol ‘K’. That is shorthand for 1,024 -
| don’t worry about why K means 1,024,
it’s just one of those things. So. ‘8K’
means 8 x 1,024 = 8,192 characters.
Chips that pass in the
night
Electronics these days is about switch-
ing streams of electrons (or electricity)
and it is only 60 or 70 years old. In early
days a kind of switch called a relay was
used; they were comparatively slow to
operate, though.
‘Slowness’ here means a few
thousandths of a second, which sounds
fast until you realise that even a simple
internal operation looks complicated
when you reduce it to a number of
switches opening and closing - and for
One operation that typically means sever-
al thousand, several million switchings.
They all mount up.
So the advent of vacuum tubes in the
1950s pleased everyone. They operated
rather faster. Transistors followed, a few
years later, faster still and more reliable.
| The major breakthrough of the early
1960s was the integrated circuit, and that’s
where we are now.
Even faster and even more reliable,
integrated circuits were also considerably
cheaper and much more compact. They
used the relatively new technology of
to cram an
increasingly large number of electronic
switches on to a decreasingly small silicon
chip.
So you’ve heard of silicon chips?
Silicon materials happen to be the best
way at present of putting the maximum
number of circuits — at least 100, more
usually several thousand - on to a really
small area of crystalline material.
That, in turn, is encased in a block of
plastic with legs; each leg corresponds to
and is connected to one of the circuit ends
on the chip. The little lot plugs into, or is
soldered into, a socket on a printed
| circuit card, which is sometimes called a
printed circuit board and abbreviated to
the PCB.
Those boards are fibre-glass or plastic
rectangles with circuit lines printed on to
them. The lines are gold or silver or some
PRACTICALCOMPUTING July 1979
other electrically-conductive metal and
they run between the socket holes; put
the correct semiconductor packages into
the correct holes and the chips can pass
electronic signals which mean actual data
to each other.
You can’t put all the chips you need on
to a single PCB — yet. So the chips on one
board have to have some way of com-
municating with the chips on another.
They also have to have some way of
getting information to and from the rest
of the system, and they need some
electrical power to work in the first place.
So a PCB has a line of circuit connectors
along one or more edges; they are the
other end of the circuit lines which
connect the socket holes.
Processor power
You plug the circuit boards into slots in
a kind of metal skeleton frame. This has
built-in wires connecting one slot with
another, and all slots with the electricity
supply and the other parts of the system.
The connectors along the edge of the
PCB mate with connectors in the frame,
so there’s a way of passing signals to and
from the PCB via the frame.
A processor isn’t a computer, obvious-
ly; it is just One component but it is an
important component because it decides
PRACTICAL COMPUTING July 1979
exactly what the computer can and
cannot do.
A microprocessor is a small processor.
That doesn’t do it justice - a microproces-
sor represents a major technological
advance, because on one or two chips the
designers have managed to cram all the
circuits for which conventional compu-
ters have several chips.
There are three important implications
of this. Microprocessors are cheap to
mass-produce, they are fairly small and,
for various technical reasons, they can’t
be as powerful or as fast as their
upmarket brethren.
You might meet four names among
microprocessors. None is a computer, but
they are the most widely-used micropro-
cessors which feature in small computers.
@ Intel 8080 — and some family relations
like the 8048. Intel made the world’s first
microprocessor in 1971, and this is now
the most popular micro. It is used, among
others, by Processor Technology, the
Compelec Altair system, the Heathkit H8
kit computer, the Imsai line, and the
Compucolor II.
®@ Motorola 6800: Motorola is probably
No 2 in the microprocessor business; like
Intel and most of the micro manufactur-
ers, it sells the bulk of its production to
industry and other users outside the kind
es Your first computer
of computing of which we are talking.
The best-k nown 6800-based system in our
field is the SWTP computer sold by
Computer Workshop.
@ MOS Technology 6502: This micro
bears a passing resemblance to the 6800
and it is used widely in so-called personal
computers. Among those are the manu-
facturer’s own Kim-1, the similar Super-
board II from Ohio Scientific ~ other
Ohio computers also incorporate it; and
above all the Pet, whose maker, Commo-
dore, owns MOS Technology; and the
Apple II.
@ Zilog Z-80: Zilog was set up by some
people who left Intel with the aim of
building a similar microprocessor — only
better. To some extent they succeeded.
The Z-80 is well-liked by those who know
about such things and is used by the
North Star Horizon, Tandy TRS-80, and
the Nascom-1, among others.
Thanks for the memory
A particular arrangement of particular
chips will provide the functions of a
processor. The same kind of technology
is applied differently to provide other
parts of the computer system, including
the memory.
There are various ways of storing
information — especially programs — for
future use. They differ primarily in speed
of access. You read information fastest
from read-only memory or ROM. It is so-
called because you can’t ‘write’ new
information on to it.
ROM is physically one or more of
those plug-in semiconductor packages.
Its contents are usually fixed by the
manufacturers and consist generally of
frequently-used programs without which
your system couldn’t really operate.
Then there is read/write memory,
whose contents you can alter. Sometimes
it’s called random-access memory, or
RAM. This is the main ‘user’ memory of
the system, sitting there waiting for you
to fill with your own programs or the data
on which your programs will operate.
Finally there are various external stor-
age devices, the slowest for the computer
to get at but also the cheapest. These are
connected usually by cable to the box
which houses PCBs of the processor.
The two external storage media you
will encounter are tape and disc and the
slowest and cheapest versions of each are
cassette and floppy disc.
Cassettes as used with computers are
much the same as ordinary audio cas-
settes; on the cheaper computers they are
audio cassettes sometimes. Certainly the
cassette units are sometimes off-the-shelf
portable tape recorders.
Cassettes are obviously a cheap form of
storage; you can buy one of. those
recorders for well below £30, after all,
and the cassettes aren’t expensive. They
are, however, limited. You can’t read
from or write to cassette at the speeds
(continued on next page)
55
(continued from previous page)
possible with disc. More important, cas-
settes store data serially. That means one
piece of data is stored after another and if
you want to reach a particular item you
have to pass over everything which
precedes it on the tape.
You don’t have that disadvantage with
floppy discs. They are in two sizes, one
about the diameter of a 45 rpm record
and other around two-thirds of it. They
really are discs, and they really are
floppy, though to give them at least some
rigidity and some protection they arrive
in cardboard envelopes. They have slots
cut in them to expose the disc surface so
that the read/write head can make con-
tact with it.
Faster
Discs are much faster at getting data to
and from the processor. They also allow
what is called ‘random’ access to data
stored. It isn’t really random - it just
recognises the fact that you can tell the
read/write head to move over the disc
before it does any reading or writing.
With audio tape, there is no simple way
of getting to the start of a particular taped |
song on cassette. The same applies to
data on a cassette but just as you can
move a record arm over an LP to the
correct point, so the computer can move
the read/write head to the proper point
on a floppy disc. That can be very
important, as we shall see later.
There is one other form of storage
which you might come across ~ paper
tape. It stores data in a form you can see.
A reel of paper tape contains holes
punched across the tape, there can
usually be up to eight of them corres-
ponding to the eight-bit binary code and
each hole denotes a ‘1’ position in that
code. No hole means a ‘0’.
Paper tape is very slow to read and
slower still to punch and the special
reader/punch unit which does that is
expensive; it is also noisy. Still, it’s a clear
and simple method of storing data and if
you already have the reader/punch
mechanism, it might be worth consider-
ing.
1/O is input/output and the two are
usually bracketed because the one device
often provides both functions; it’s easier
to build it that way.
The visual display unit or VDU is the
classic example. It comprises an input
device (the typewriter-like keyboard) and
an output device (the television-like
screen), but a VDU manufacturer finds it
convenient to provide one cable for
connection to the processor.
In fact, that cable contains some wires
specific to the imput function and some
for output; since the computer knows
which is which, the VDU isn’t really a
single device at all. In any case, many of
today’s smaller computers make a physi-
cal] distinction between a display and the
keyboard.
Alternative
Another I/O device encountered fre-
quently is the keyboard/printer terminal,
an alternative to the VDU but with a
printer instead of a screen. You might
also have a totally separate printer with
no keyboard; you will certainly need one
if you intend to use your computer system
for your business.
The are other more esoteric forms of
I/O. One which appeals particularly to
technology buffs is speech; the computer
recognises what you’re saying, and it
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56
@ Circle No. 164
PRACTICAL COMPUTING July .1979
replies vocally, too. The voice output
part is more or less possible now, though
it’s not exactly broadcasting quality;
voice input is proving more of a problem.
What is a personal
computer?
You can forget most of what has gone
before because today you can buy off-
the-shelf a fully-fledged plug-in-and-go
computer system which requires you to
| understand as much about electronics as
| the buyer of a music centre knows about
hi-fi. Frankly, though, in both cases you
will have more pleasure from your
purchase if you know what’s going on
inside.
That off-the-shelf buy is what is usually
called a personal computer — the em-
phasis being on the individual user.
Though you might buy one for your
business, you will also be the principal
user. By comparison, larger computers
sometimes occupy full-time staff who do
nothing but work with the computer but
who didn’t select it and who didn’t sign
the cheque.
Let’s start at the bottom. The most
basic personal computer looks like this:
@ Input: typewriter-style keyboard.
@ Processor: totally invisible, probably
buried somewhere inside the keyboard
on a couple of circuit boards.
@ Storage: internal memory is probably
there, too, on one or two more PCBs.
External storage will be a cheap cable-
connected keyboard.
@ Output: a screen, possibly an ordinary
portable TV set slightly amended.
The three best-sellers at the bottom
end of the personal computer market
exemplify different approaches.
@ Commodore Pet: less than £500. One
unit containing keyboard, built-in cas-
sette unit, and screen.
@ Tandy TRS-80: less than £500. Four
separate units — screen, keyboard (incor-
porates the processor and memory),
cassette player, power supply.All com-
puters need a black box to convert mains
voltage to the current they use; in most
computers this transformer is invisibly
inside another unit.
@ Apple II: less than £1,000. Three
separate. units — colour TV, keyboard
(incorporates processor, memory and
power supply), and cassette unit.
As for software, all have an operating
system of some kind - typically a ROM
chip or two which contain all the low-
level binary decoding functions which
make things work; you won’t need to
know anything about it, though. You will
also have a programming language called
Basic.
Remember all that decoding the com-
puter is doing to save you having to
| communicate with it in binary? Well, that
conversion process can be extended and
most of today’s computers allow you to
use a near-English ‘language’ called
Basic.
PRACTICAL COMPUTING July 1979
It is fairly easy to learn and it’s easy to
understand. In general, the syntax and
vocabulary of a programming language
like Basic are simpler to grasp than the
tules of a foreign human tongue.
Basic has become popular partly be-
cause it was devised from the start as a
beginners’ language. It had little compe-
tition; and the business of translating it
into binary digits for the computer — the
so-called ‘machine code’ — didn’t require-
as much space or effort from the com-
puter as other programming languages.
Today you might also hear about
PASCAL, a language with similar aspira-
tions but it is only just starting to appear
on small computers. The only other
serious contender is Cobol, a long-
winded language for business use which
really scores only when you are already
familiar with it, perhaps by using it
previously on a big computer.
What can it do?
Peter Ustinov’s biography compares
TV to telephones. If someone asked you
whether you like telephones, you would
have to say it depends who is on the line
and what they are saying. The same
applies to TV and it’s also true of
computers.
A small computer can do something for
everyone. That is an over-simplification,
of course, but in practice it can probably
do something for you, provided you tell it
what to do. If the job you have in mind
es Your first computer a
can somehow be expressed as a series of
rules or instructions in the form of a
computer program, the computer can do
it.
There are two ways of putting in a
program. You can key it in yourself, or
you can ‘load’ it from cassette, disc or
‘paper tape, in which case someone else
will probably have written the program
and sold it to you ready for loading in that
form.
So you can put in a program you’ve
written yourself or you can load someone
else’s. What those programs do is limited
only by your imagination - within reason.
Here are some examples we’ve heard
of:
@ Games. It’s easy to regard computer-
ised games as trivial and irrelevant. In
fact, game-playing obviously can be
intellectually and emotionally stimulating
as well as merely diverting.
@ Simulations. There’s a cross-over
point which illustrates the value of
games. Simulating the economy of
Sumaria or the starship Enterprise might
be games but there’s little which is
different about planning the future of
your company or looking at alternative
ways of getting you and the family to
Dubrovnik this summer.
A good example is in education, where
a history teacher might use the classroom
computer to decide ‘what if’ questions
and thus bring historical situations to
(continued on next page)
57
(continued from previous page)
life. A recent prizewinner in a Practical
Computing competition is doing that with
a variety of situations, including the
Norman Conquest - the pupils take parts,
make decisions based on the historical
situation, and watch the computer decide
what the outcome would be.
@ Education. This could be applied
equally to geography and science sub-
jects. The computer can also be used with
obvious benefit in complicated calcula-
tions at school; but most teaching and
much school administration could also
gain from some automation of the more
routine functions.
@ Business. The same applies to the
administration of business, though the
returns are visible and financial. Stock
control is an obvious example. A small
computer could tell the shopkeeper or a
retailer the current stock position at any
time on all items, which were selling fast
or slowly, which were approaching re-
order levels, and how quickly the supplier
could deliver. With that amount of
information you ought to be able to cut
back inventory levels and save money.
You could well do the same for debtors
if you have a big sales ledger, and you
should certainly look to save time by
having the computer produce invoices
with VAT analyses as an automatic by-
product. It might also produce ‘personal-
ised’ form letters or quickly-updated price
APPLE"
PET"
TRS 80°
ie,
SOFIWALS
DOUSG
44 Berners Street, London W1P 3AB
58
SORCERER’
SUPERBOARD"
Please send large S.A.E. for list
lists if your business involves those.
@ Home. There is more rubbish talked
about computers in the home than any
other area of this subject. True, a
computer can run your bath, feed the cat,
switch on the TV and change the record
but the extra items of hardware you
would need could become complicated
and expensive. In any case, who needs it?
There are, however, some sensible
home applications. Playing games and
doing household accounts are obvious
candidates. If you’re writing a novel, the
computer might help, too. You’ll need
some skill to put a microprocessor into a
Programs for your
vacuum cleaner but that’s a chore worthy
of automation. There is also some scope
for having the computer control your
home while you’re away — feeding and
watering your houseplants, perhaps, or
turning a video recorder on and off at
longer intervals than the VCR manufac-
turer allows.
@ Art. Computer-generated art is not to
everyone’s taste, but at the very least you
can have plenty of innocent fun persuad-
ing your computer to produce patterns,
poems, animated cartoon-like sequences
and even music, though you might need
special hardware. Some highly serious
work has been produced with the com-
puter, so don’t take it too lightly.
What to look for
As with motor cars or hi-fi systems or
sorbets, there are no hard and fast rules
which do not rely ultimately on personal
preference, but here are some points to
consider:
@ Processor: It doesn’t matter whose
processor is inside your computer unless
you want to get into it with your soldering
iron, in which case you shouldn’t be
reading this.
@ Standardisation: Much more impor-
tant is to consider what you might want to
add in the future. Some personal compu-
ters follow a standard arrangement of
connectors for the slots in their metal
frames; so into those slots you can put.
Micromedia (Systems)
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@ Circle No. 165
selection of computer books.
Sophisticated Application software available, either packaged or
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@ Circle No. 166
PRACTICAL COMPUTING July 1979
any PCB which obeys the same standard
arrangement,
The best-known standard is called S-
100. If you think you'll. want to add
goodies, you might well opt for a
computer with the S-100 standard. Don’t
be too dismayed if your favourite compu-
ter doesn’t have it; it reduces choice but
it’s not a disaster.
The other important standard to ask
about is called RS-232; also known as
CCITT V24. This refers to external
connectors, the means whereby you can
attach printers and other peripherals to
your computer. Again, RS-232 increases
the options and it’s probably more
important to have it-than S-100.
@ Read-only memory: ROM is generally
a good thing. If you have to load the basic
system software into the computer each
time you want to use it, you don’t have
ROM in your.computer. Having these
functions pre-programmed and ready to
go in ROM modules saves time and you
won’t have any load problems - they
happen occasionally. Still, this isn’t some-
thing for which there is much choice
about; either you have it, or you don’t
have it.
@ RAM: Read-write memory is much
more important. The pressing question is
how much do you need? And theye’s no
easy answer.
Determine how much memory you can
have for your programs and. data, be-
cause most personal computers put some
of their basic system software in RAM,
whether you like it or not.
Then you might look at what. your
input takes up. For. instance, if you
wanted to put in a full A4 page of text
you would need almost 4K of memory to
store it. A relatively complicated game
with many twists and turns, like most of
the versions of Star Trek, will need 7K or
8K.
There’s a variant on Parkinson’s Law
here — you almost always use all the
Memory you have, whatever size it is.
Aim for at least 8K and try for 16K if you
can afford it; you'll want to run fairly
‘sophisticated’ programs sooner or later.
@ Programs: Go for Basic. All personal
computers have a Basic and it has
become the lingua franca in which
programs are exchanged. Beware,
though, variants of the language are not
interchangeable, and you can’t load a
Basic program written for a Pet into a
TRS-80 and expect. it to work.
If you buy one of the more popular
personal computers -— Pet, TRS-80,
Apple I — you will find there is a good
deal of ready-made software on sale in
the form of cassettes (£3 to £25) and
diskettes (usually £10 to £50).
Check whether your computer uses an
operating system called CP/M or a floppy
disc drive made by. North. Star; again,
there is plenty of off-the-shelf software
available (on floppy disc) for these.
@ Keyboards: Unless you have a compu-
PRACTICALCOMPUTING July 1979
| characters but you will
ter with a decent keyboard, you can have
all kinds of problems trying to type-in a
program. A good all-purpose keyboard
follows the QWERTY typewriter layout.
It has a solid, chunky feel when you
depress keys and it has a big, unmissable
RETURN key - this you use to tell the
computer you have concluded one line of
input and want to start the next, so it is
used frequently.
Extras on it might include a separate
numeric keypad on the right (speeds the
entry of numbers) and a CAPS LOCK
key in addition to SHIFT LOCK - locking
into capitals means only that you can
press all the non-alphabetic keys and still
get whatever is in the lower-case position.
@ Display: Go for a big display if you
can. A good-sized display produces more
information more quickly and in more
alternative shapes and sizes than a printer
or a small display. ‘Big’ in this context
means it should be able to show at least
16 lines of 64 characters.
Displays are in three varieties. You
ought to obtain the best possible results
from a purpose-built visual display unit
(VDU). They normally display 24 ines of
80 characters, but they will generally add
at least £500 to the cost of the system.
A built-in screen like that on the Pet or
Compucolor II might not display so many
get special
graphics symbols and no need for cabling.
es YOur first computer a
The third type is simply a converted
TV, the simplest and the cheapest kind of
display, though it might not produce the
sharpest image.
@ Power supply: Translating the mains
power into the electricity your computer
needs is the job of a chunky component
usually called the power supply. In fact,
it’s a voltage transformer like the one
used by a model train or racing car
layout.
It is possible to overload the power
supply, in which case things get hot and/
or frail. So look for really beefy transfor-
mers and hefty wiring. Also get some
advice about how much you can plug into
the system’s existing power supply before
it needs a hand.
Computers dislike variations in the
electric current. This may result in the
appearance of wobbly characters on the
screen, or data being lost between the
processor and cassette or disc, or at
worst, some component failing.
Voltage variations are inevitable in
mains electricity and if your computer is
plugged into the ring main you may
compound the problem by having other
electrical appliances switching on and off
- refrigerators, stereo set-ups, irons,
heaters.
Ask someone’s advice about voltage
regulators. For an average personal com-
(continued on next page)
59
(continued from previous page)
puter you could buy one for £25-£50, it
plugs into your mains socket, and you
plug the computer into it. The regulator
evens out the dips and peaks in the power
supply cleverly, delivering a smooth flow
of electricity to your computer.
@ Printers: Sooner or later you'll want a
printer to keep a record of your programs
— you might lose or damage a cassette,
after all. For some applications, like
business uses or word processing, a
printer clearly is vital.
The immediate problem is connecting a
printer to your computer. Having
specified an RS-232 interface means you
can attach almost any printer; otherwise
your options are more limited.
There are two types of printer. There is
high-quality, typewriter-like_ printing
from daisywheel printers (£2,000 or
more) or from converted IBM golf-ball
typewriters (£1,000 or more but rather
slower). Dot-matrix printing is a techni-
que whereby characters are built up from
dots, and because those printers are
mechanically simpler, the prices are
lower — down to around £300 for a very
small and slow printer which can manage
only 40 characters to a line. In the range
£700 to £1,000 you will get a faster printer
(60 to 120 characters per second) which is
good enough for anything but top-quality
printing.
@ Storage: Using cassette tape or floppy
disc for storage gives you a cheap and
easily-expanded alternative to keeping
data and programs in RAM.
The cheapest kind of cassette system
loads at something around 50 bytes per
second, and the fastest rarely exceed 300
bytes per second; it could take several
minutes to transfer a complex program.
If you can afford it, choose floppy discs
— their chief virtue is that they operate at
much higher speeds, taking far less time
to transfer information. This saves on
boredom but it also allows you to make
better and more imaginative use of your
system.
In any case, your computer may well
be doing jobs all the time which involve
looking-up records; you need the speed
of disc storage for this.
@ Documentation: Personal computers
generally have inadequate user instruc-
tions and reference manuals. These days
the accompanying documentation tends
to be better-produced and some of the
learner-level starter manuals are really
good. Even if you are sure that all the
information is there somewhere, it can
still be very difficult to read via an index
or the contents page. Quantity is no
substitute for quality.
@ Users: You should also look for an
active users’ newsletter, perhaps even a
specialised user group. Both are media
for exchanging opinions, advice, notifica-
tions of errors, and potentially useful
programs.
@ Supplier: You'll come across three
60
kinds of supplier — single-system special-
ists, single-system generalists, and com-
puter stores.
The last category is probably the most
important. The computer store sells
several types of computer, several types
of printers and disc drives, and almost
everything you need for your computing
— paper, discs, tapes, books, magazines, |
the lot. Those places should serve as local
social centres for the personal computer
community, repositories of knowledge
and advice and notice-boards for ex-
changes, advice and information — or that
is how. it should be. If: your local
computer store doesn’t seem like that,
tread warily.
The second group. comprises mainly
Pet and Tandy dealers, retailers who
handle other products — typically audio
systems or hobbyist electronics, some-
times other consumer electrical goods —
but who sell only one brand of computer,
normally at rock-bottom prices.
The single-system specialists typically
make their money from knowing a great
deal about the one brand they sell and by
selling you many extras for it, including
perhaps some programs written by them
to your specifications. Some computers
you cannot obtain anywhere else. If you
need a relatively complicated system to
do certain specific tasks, that kind of
supplier is your best bet.
What to buy?
Ensure you know what computers can
and cannot do; then decide more or less
what you want from a computer. The first
decision should be what type of computer
to consider, and there.are four categories
to look through:
@ Hobby computers: Typically costing |
less than £300, they require some techni-
cal knowledge. They are either build-it-
yourself kits — not too difficult to
assemble — or ready-built computers on a
single printed circuit board - with some
memory but not much, and with no
protective casing around it.
es Your first computer mama
They may have a built-in keyboard for
input; they may have a small display for
output. Some have neither, some have
both, one has a keyboard and a tiny
printer on the PCB.
All have connectors to attach cassettes,
printers, or other external devices. Most |
have Basic; some have only their own
cryptic programming languages. Exam-
ples of this breed are the Kim-1, Aim-65,
Nascom-1, and Ohio Superboard II.
@ Games growing up: Again less than
£300, they are a spin-off from the TV
games you see for a few pounds. The
more complicated allow you to plug in
new cassettes for more games. Since
these so-called games centres are essen-
tially microcomputers with the games
| cassettes being programs, you could add
a keyboard and program them yourself.
Some of the games manufacturers now
allow you to do that. It’s already happen- |
ing in the States, and there will be similar
products this year in Europe, from
Philips and others.
@ Appliance computers: Denotes com-
puters designed to be sold, taken home, |
plugged in, and used just like any other
domestic applicance, TV or washing
machine. The Commodore Pet was the
first and the best example. It’s compact,
simple to use, and is in one piece. Against
that, it’s not particularly expandable. The
newer model is more expandable but you
have to add extra external items, like a
printer and floppy disc drives.
A more recent arrival in this genre is
the Compucolor II — more expensive but
it incorporates floppy disc rather than
cassette and it gives you a full colour
display rather than black and white only.
Further up-market there are several plug-
in-and-go computers, so the price spread
is from £500 to more than £5,000. The
more expensive ones are designed for
business use, of course, and they assume
generally that you will be attaching at
least one external device — a printer.
@ Building-block computers: They sepa-
rate the I/O, external storage and proces-
sor functions into different boxes and
connect them by cable. The processor
box contains the memory and may
contain floppy disc drives, too, as in
North Star Horizon. The Apple II, Tandy
TRS-80 and Processor Technology Sol
exemplify an alternative design trend by
putting the processor and memory into
the keyboard.
The attraction is simple. To uprate one
area of the system you can disconnect the
existing unit and plug in a better one,
and/or you can attach more of the same,
and/or you can add extras.
So you could swop a slow but cheap
cassette for a fast but expensive floppy
disc when you can afford the difference.
You can attach more memory or a second
disc if you want more storage. You could
plug in a special typewriter-quality print-
er or one of those voice output devices if
you want some extra facilities. @
PRACTICAL COMPUTING July 7979
eared elect name For Hardware, Software,
CC MICROCOMPUTERS ETL iss
PET CE commodore
. Pet2001 TRS 80
From £435 = From £350
NEW PET 2001 with large keyboard.
From £ 630.00
PET 2001-16N (16K RAM and New Large Keyboard) £630.00
PET 2001-32N (32K RAM and New Large Keyboard) £750.00
PET 2001-4 (Standard PET with 4K memory) £435.00
PET 2001-8 (Standard PET with 8K memory) £515.00
PET 2040 (Dual Drive mini-floppy 343K User Storage) £695.00 | TRS 80, 4K Level 1 (Keyboard with 4K memory+
PET 2023 (80 col. dot matrix printer with PET graphics) £515.00 VDU+Cassette drive+240v PSU) £435.00
PET 2022 (as above with tractor feed) £605.00 | TRS 80 16K Level I (as above but with Level IZ
tEEE/RS232 Serial Interface ‘A’ Output only £106.00 basic and 16K memory) £665.00
1EEE/RS232 Serial Interface ‘B’ Input/output £186.00 | TRS 80, 4K Level I — Keyboard+240v PSU only £350.00
|IEEE-488/Centronics type parallel Interface £45.00 | TRS 80, 4K Level II — Keyboard+240v PSU only £420.00
PET C2N External Cassette Deck £50.00 | TRS 80, Expansion Interface with 16K RAM £325.00
Interface to $100 (4 slot motherboard) £112.00 | TRS 80, Expansion Interface with 32K RAM £435.00
Sorceror a eee TVJ 232T Serial Interface for TRS 80 £45.00
/ a Zs S'—1} Screen Printer for TRS 80 (text+graphics) P.O. A.
Now with the / « | Expandor Black Box Interface for TRS 80 £48.00
$100 Bus Expansion = '-) Expandor Black Box Power Supply for TRS 80 £49.50
interface and Dual } Authorised Centronics Micro Printer Interface for TRS 80 £45.00
Drive min-floppy Disk Dealers Centronics Parallel Printer Interface for TRS 80 £45.00
— Disk Drives for TRS 80 — see Disk Drives
Sorceror 16K RAM (inc. UHF Modulator) ~—™ £740.00 | UHF Modulators (encased with leads for 625 lines) £20.00
Sorceror 32K RAM (including UHF Modulator) £840.00 | RAM upgrade (4-16K, 16-32K, 32-48K)
Exidy Video Monitor (High Resolution) £240.00 Supplied and fitted at our premises £110.00
Exidy Dual Drive mini-floppy disk (630K Storage) £1200,00 | Upgrade to increase speed 1.78 MHZ to 2.66 MHZ £13.00
Exidy $100 Bus with Interface+Motherboard+PSU £200.00 } ‘Bleeper’ for CSAVE/CLOAD & key functions £40.00
Exidy Mini-floppy Disk Drive (143K Storage) £495.00 | Switchable selection of Level I or Level IL ( ROMS required) £25.00
5 P Automatic volume control (AVC) for CLOAD £25.00
Disk Drives ‘Electric Pencil’ text/word processing package (on cassette) £65.00
Shugart Mini-floppy Disk Drive (including PSU) £350.00 | ‘Electric Pencil’ text/word processing package (disk version} £115.00
Micropolis Mini-floppy Disk Drive (incl. PSU) £350.00 J ‘Electric Pencil’ keyboard mod. to give lower
Percom FD200 Mini-floppy Disk Drive (including PSU) £350.00 case with text/word processing package. £28.00
SMS STD floppy Dual Drive (+controtler+PSU+Case $100 Interface for TRS 80 P.O.A.
for 2.5Mbyte £2500.00 } ‘Library 100’ — 100 progs for TRS 80 on cassette (Level II) £39.00
Pertec 10MB Top Load Hard Disk System . i ieee
(with controller+disk basic) £6400.00 | Printers Pir |
APPLE Il TELETYPE 43 KSR £875.00 ji / k
Keyboard send/receive Serial printer for / ue, /
Apple mini-floppy Disk Drive (116K Storage) £425.00 PET or TRS 80 ; My /
ITT 2020 incl, PAL Modulator (16K RAM) £895.00 J (interfaces or friction feed extra) i
RS 232C Serial Interface for |TT 2020 Motherboard P.O. A. | Teletype 33 KSR Serial (110 Baud) Reconditioned ==’ £550.00
Parallel Input/Output Interface for 1TT 2020 Bus P.O. A. | Expandor Black Box (80 column impact printer) £375.00
Palsoft on ROM Board (extended Basic) P.O. A. | Centronics 779 parallel(friction feed) £790.00
ITT 2020 Authorised Dealers Centronics 779 parallel printer (tractor feed) £890.00
ALTAIR Centronics 701 parallel printer, Bi-directional+
: . : tractor fed £1375.00
300 Multi-User, Multi-Tasking system+floppy and Centronics micro printer (20, 40, 80 columns selectable) £395.00
hard disk optionstpractical business applications P.O.A. | QUME daisy wheel serial printer, 45 cps from £2195.00
Software In/Out
Petsoft COMPUSETTES Coen Ge GEMSOFT } Altair 6801/2 Analog/Digital convertor board $100 £382.00
(Authorised Dealerships, Send for Catalogues) Altair 6804 Process control interface 8 output relays/12
PILOT (for TRS 80) text orientated language ecm awe O° ae as
COMAC — Computerised Accounting for TRS 80 £50.00 Cell al ;
STOCK CONTROL — (for TRS 80) incl. Inventory, Terminals
Purchase Orders and Invoicing £125.00 | Soroc 10120 VDU/Keyboard — 80 char./24 lines £660.00
Estate Agents/Employment Agency Systems — Cypher CUB VDU+separate keyboard £380.00
Ete, — Fortran 80 — Cobol 80 — Pascal Ansaback ‘Phonemate’ Telephone Answering Machine, voice
tc. operated twin cassette £190.00
Diskettes 5% (blank) boxed (min. order 10) each £3.00
C60 Cassettes (Min. order 10) each £0.40 enices EXCLUDE VAT, FREIGHT & HANOLING. SEND OR
CBM KIM 1 Microcomputer System £94.00 oa Sei pave of compilation) :
Computatker Speech Synthesis for S100 £350.00 | birectors: Dr. R.V. King, BA, MIEE. [AARC ACARD |
Books — Large range at Microcomputer related books & magazines, a2 Pelle he, pase maim cam | = =
If you don't see it — ask if we have it. AS. Barton, ACII, ABIBA, CdipAF. J
T & V JOHNSON (MICROCOMPUTERS ETC) LTD.
Member of the TV Johnson Group of Companies
@ (0276) 62506..."
Telex 858893
165 London Road, Camberley, Surrey GU15 3JS Eves. Basingstoke (0256) 24787 and Farnham (0252) 721094
(+ ansaback during office hours)
Hours of business 9.30—5.30 Mon-Fri. 9.30—1.00 Sat.
Branches at: Birmingham, Bristo!, Edinburgh, Leeds, London, Louth,
Newmarket, Nottingham, Oxford, Byfleet, Wokingham.
@ Circle No. 167
PRACTICAL COMPUTING July 1979 61
62
—— =
DISTRIBUTED DATA PROCESSING
THE LARGEST DISTRIBUTOR OF THE ITT2020
SERVING NORFOLK, SUFFOLK, ESSEX,
CAMBRIDGE, LONDON CITY & WEST END
OFFERS THE FOLLOWING:
HARDWARE
ITT2020 16K Upgrade Kit £85
Apple 16K Upgrade Kit £90
NEW Black & White Monitor £145
NEW Colour Monitor £280
NEW Larger Capacity Disk Drive Price on Request
ALL ITT2020 & Apple Compatible
Also Available all 1TT2020 peripheral equipment
SOFTWARE
The ‘PROFESSIONAL’ systems available
include the following
Sales Ledger
Purchase Ledger
Nominal Ledger
Financial Planning
Payroll
Stock Control
ALL Hardware & Software will be on view at
Stand 5 in the ‘Micro Systems Exhibition’
|
DISTRIBUTED DATA PROCESSING LTD
Details can be obtained from ESSEX HOUSE
DDP SALES 0268 727474 CHERRY DOWN
DDP HEAD OFFICE 0268 282155 BASILDON
ESSEX
a —~
ys
@ Circle No. 168
PRACTICAL COMPUTING July 1979
SHOWGUIDE
INCORPORATING THE
DIY COMPUTER FAIR
Bloomsbury Centre Hotel,
London
July 5-7, 1979
Online Conferences Ltd
Cleveland Road, Uxbridge, England UB8 2DD
Telex: 261173. Cables: Online eeeal
Telephone 0895 3926.
63
64
From Science of Cambridge: the new MK 14.
Simplest,most advanced,most flexible
8-digit, 7-segment,
LED display
f
!
mil
i
{| eee
4 Ur WIN
7 Pi se N
MK 14 including ean \
optional RAMI/O
and Extra RAM.
The MK 14is a complete microcomputer with a
keyboard, a display, 8 x 512-byte pre-
programmed PROMs, and a 256-byte RAM
programmable through the keyboard.
As such the MK 14can handle dozens of
user-written programs through the hexadecimal
keyboard.
Yet in kit form, the MK 14 costs only £39.95
(+£3.20 VAT, and p&p).
More memory —and peripherals!
Optional extras include:
1. Extra RAM-—256 bytes.
2. 16-line RAM I/O device (allowed for on the
PCB) giving further 128 bytes of RAM.
3. Low-cost cassette interface module-which
means you can use ordinary tape cassettes/
recorder for storage of data and programs.
4. Revised monitor, to get the most from the
cassette interface module. It consists of 2
replacement PROMs, pre-programmed with
sub-routines for the interface, offset
calculations and single step, and single-
operation data entry.
. PROM programmer and blank PROMs to set
up your own pre-programmed dedicated
applications.
All are available now to owners of MK 14.
wr
A valuable tool—and a training aid
As acomputer, ithandles operations ofall
types —from complex games to digital alarm
clock functioning, from basic maths to a pulse
delay chain. Programs are in the Manual,
together with instructions for creating your own
genuinely valuable programs. And, of course,
it’s a superb education and training aid -
providing an ideal introduction to computer
technology.
4.43 MHz crystal
| @°¢Z
PROM -512 bytes
RAM —256 bytes
ExtraRAM
(optional)
Edge connector for
. external keyboard with
upto 32 keys
SPECIFICATIONS
@Hexadecimal keyboard @ 8-digit, 7-segment
LED display ® 8 x 512 PROM, containing
monitor program and interface instructions
©256 bytes of RAM © 4 MHzcrystal@5V
regulator® Single 8 V power supply @ Space
available for extra 256-byte RAM and 16 port
VO e Edge connector access to all data lines
and I/O ports
Free Manual
Every MK 14 kit includes a Manual which deals
with procedures from soldering techniques to
interfacing with complex external equipment.
It includes 20 sample programs including math
routines (square root, etc), digital alarm clock,
single-step, music box, mastermind and moon
landing games, self-replication, general
purpose sequencing, etc,
To: Science of Cambridge Ltd, 6 Kings Parade, Cambridge, Cambs., CB2 1SN.
Please send me the following, plus details of other peripherals:
CI MK14 Standard Microcomputer Kit @ £43.55 (inc 40p p&p.)
CI Extra RAM @ £3.88 (inc p&p.)
LIRAM/Odevice@ £8.42 (inc p&p.)
I enclose cheque/money order/PO for £
Name
CPU
z Display and keyboard
interface circuitry.
Address (please print)
Allow 21 days for delivery
Ce
microcomputer -in kit form.
5 V regulator
Power rails and
(optional)
PROM-
ExtraRAM
(optional)
Designed for fast, easy assembly
The MK 14 can be assembled by anyone with a
fine-tip soldering iron and a few hours’ spare
time, using the illustrated step-by-step
instructions provided.
How to get your MK 14
Getting your MK 14 kit is easy. Just fill in the
coupon below, and postit to us today, with a
cheque or PO made payable to Science of
Cambridge. And, of course, it comes to you with
acomprehensive guarantee. If for any reason,
you're not completely satisfied with your MK 14,
return it to us within 14 days fora full cash
refund.
Science of Cambridge Lid,
6 Kings Parade, Cambridge, Cambs., CB21SN.
Telephone: Cambridge (0223) 311488
(indicate total amount.
Science of
Cambridge
PRACTICAL COMPUTING
input/output edge connector
RAM I/O device
512 bytes
RAM-256 bytes
5
al
@ Circle No. 169
CONFERENCE
PROGRAMME
INTRODUCTION TO THE USE
OF MICROPROCESSORS IN
LIGHT INDUSTRY.
Thursday, July 5. Chairman:
John Coll, Head of Electronics,
Oundle School.
KEITH BAKER, UNIVERSITY OF
SUSSEX: Microprocessors and
the Product.
HOWARD KORNSTEIN, INTEL
CORPORATION: Future trends
in microcomputer technology.
MIKE GURR, BOC: Getting into
Micros.
JOHN COLL, OUNDLE
SCHOOL: Software simplified.
BARRY STANDRING, INTEXT:
Business Information Services.
ALL SPEAKERS: Panel discus-
sion.
PERSONAL COMPUTERS IN
BUSINESS
Friday, July 6. Chairman: Keith
Baker, Lecturer in Computer
Science, University of Sussex.
PORTIA ISAACSON, ELEC-
TRONIC DATA SYSTEMS
CORP., U.S.A.: The personal
computer, trends and develop-
ments.
ADAM OSBORNE, OSBORNE
AND ASSOCIATES, U.S.A.: A
view from the States.
JOHN COLL, OUNDLE
SCHOOL: Teach yourself com-
puters.
CHAIRED BY KEITH BAKER:
Personal computer parade -
description and demonstration
of four machines.
ALL SPEAKERS: Personal com-
puter probe - questions on
demonstration.
MIKE GURR, BOC: Running
your business at home - with
micros.
CLIVE LOVELUCK, ULSTER
MANAGEMENT CENTRE: Per-
sonal computers, a new dimen-
sion in management training.
DO-IT-YOURSELF COMPUTERS
Saturday, July 7. Chairman:
Mike Gurr, Database Consul-
tant, BOC.
ADAM OSBORNE, PRESIDENT,
OSBORNE & ASSOCIATES: DIY
in the U.S.A.
GUY KEWNEY, Computing:
U.K. products evolution.
PORTIA ISAACSON, ELEC-
TRONIC DATA SYSTEMS
CORP., U.S.A.: The ‘byte’ shop
explosion.
MIKE GURR, BOC: New techni-
ques in software.
JOHN COLL, OUNDLE
SCHOOL: Case study - a per-
sonal computer built from
scratch.
PORTIA ISAACSON: The games
people play.
CHAIRED BY ADAM OSBORNE,
ALL SPEAKERS TAKING PART:
Discussion panel.
CONFERENCE INFORMATION
SEMINAR REGISTRA-
TION
“You can apply for a registration
form by writing to Online Con-
ferences Ltd., Cleveland Road,
Uxbridge, Middlesex.
REGISTRATION FEES
Thursday, July 5 — Introduction
to the use of Microprocessors in
Light Industry. £45 plus £3.60
VAT.
Friday, July 6 — Personal Com-
puters in Business. £45 plus
£3.60 VAT.
Both days — £75 plus £6.00 VAT.
The fees include daytime re-
freshments and a light buffet
lunch.
Saturday, July 7 - The Do-it-
Yourself Computer Day. £10.
The fee includes coffee and tea,
but not lunch.
GENERAL SHOW
INFORMATION
HOURS OF EXHIBITION
Thursday, July 5-10am to 6pm
Friday, July 6-10am to 6pm
Saturday, July 7-10am to 6pm
ADMISSION
Entrance to the exhibition is by-ticket only. Price £1. On Saturday,
the DIY Computer Fair day, children under 14 wil! be admitted for
50p. A special offer of three tickets for £2 is available on tickets
bought in advance. They can be used on any day. Seminar
participants will be given a complimentary exhibition ticket which
can be used on all three days of the show. Advance tickets available
from Online.
CATERING FACILITIES
The exhibition foyer has a bar and there are tea‘and coffee points in
the exhibition where snacks will be available. The Bloomsbury
Centre Hotel has full restaurant facilities.
ACCESSIBILITY
The hotel is easy to reach by Underground — Russell Square, Kings
Cross/St. Pancras, Euston and Euston Square are within easy
PRACTICAL COMPUTING July 1979
walking distance. Bus routes are two minutes’ walk away, and the
68, 77, 170, 188, 196 and 239 service the area. The hotel has a
basement car park and there is an adjacent National Car Park.
ACCOMMODATION
Online recommends that overnight accommodation be booked
through Exp-O-Tel, Strand’ House, Great West Road, Brentford,
Middx. Tel: 01-568 8765.
TELEPHONE FACILITIES
Coin boxes are situated around the hotel.
1979 Microcomputer Show, incorporating the Do-it-Yourself Com-
puter Show, is organised by Online Conferences Ltd., Cleveland
Road, Uxbridge, Middlesex. Tel: (0895) 39262. Contact: Christine
Clarke.
65
MICROPROCESSOR HISTORY
IS BEING CREATED
at 184 High Street Berkhamsted
and BOREDOM has been BANISHED
Our Client, part of an International giant, has been so successful in the micro-terminal
business, that it needs three more software designers. At least two years’ assembler
experience in a disciplined environment plus a lively and creative mind is required.
In return, the Company offers the following Five-Star package.
Really interesting design work covering micro-executives, communications etc.
Membership of a talented dynamic young team with good promotion prospects.
Good pay — starting salaries up to £7K
Big company benefits include good pension scheme, plus relocation assistance if
required.
Attractive working environment, central to shops, facilities etc. —
N.B. — there are three fine pubs just across the road.
Find out more by simply phoning:
Lionel Elton of Business Resources, at Redbourn (STD 058 285) 3888 during office hours.
Or at Aylesbury (STD 0296) 630063 during the evening or at the weekend.
or just write to Business Resources
Old School; The Common, Redbourn, St Albans, Herts AL3 7NG. B
Licensed as an Employment Agency by the D.E. Licence No. SE(A) 3211
@ Circle No. 170
DILLON’S UNIVERSITY BOOKSHOP
1 MALET STREET, LONDON WCIA 7JB Tel. 01-636 1577 (16 lines)
As visitors to our stand at the
MICROSYSTEMS ‘79 Exhibition § will
already know, Dillon’s.has one of the
most comprehensive stocks of compu-
ter books in the country. We will be
presenting an even larger display at the
MICROCOMPUTER SHOW with, of
course, special emphasis on all aspects
of mini- and microcomputers.
Our Malet Street shop is only a few
minutes’ walk from the Bloomsbury
Centre. There you will find over 150,000
different titles in more than 20 subject
departments. If you cannot visit the
shop, write to the Mail Order Manager
for details of our postal services and
credit facilities, stating your subjects of
interest.
A Pentos Company
@ Circle No. 171
66 PRACTICAL COMPUTING July 1979
LIST OF EXHIBITORS
Abacus Computers Ltd,
62 New Cavendish Street,
London, W1.
Tel: 01-580 8841
Stand 3
The Byte Shop
426-428 Cranbrook Road,
Gants Hill,
Ilford, Essex.
Tel: 01-554 2177
Stands 18, 19, 20, 25, 26, 27
CCS Microhire,
7 Peartree Dell,
Letchworth, Herts.
Tel: (046 26) 73301
Stand 15
Comart,
PO Box 2,
St. Neots, Huntingdon.
Tel: (0480) 215005
Stand 34
Commodore Business Systems,
360 Euston Road,
London, NW1.
Tel: 01-388 5702
Stand 21
Computabits,
41 Vincent Street,
Yeovil, Somerset.
Tel: (0935) 26522
Stand 6
Computer Bookshop,
Temple House,
43-48 New Street,
Birmingham, B2 4LH.
Tel: 021-643 4577
Stand 47
Comp Computer Components,
14 Station Road,
Barnet, Herts.
Tel: 01-449 6596
Stands 28 and 29
Datalogic Ltd,
29 Marylebone Road,
London, NW1.
Tel: 01-486 7288
Stand 45
Dillon’s University Bookshop,
1 Malet Street,
London, WC1.
Tel: 01-636 1577
Stand 4
Distributed Data Processing,
Essex House,
Cherrydown,
Basildon,
Essex.
Tel: (0268) 727474/282155
Stand 5
Electrical Research Association,
Cleeve Road,
Leatherhead,
Surrey.
Tel: (037 23) 74151
Stand 24
Equinox Computer Systems,
Kleeman House,
16 Anning Street,
New Inn Yard,
London, EC2.
Tel: 01-739 2387
Stand 32
Euro- Calc Ltd,
55 High Holborn, London, W1.
Tel: 01-636 8161
Stands 1 and 2
Gemsoft Ltd,
Alverstone Lodge,
Wych Hill Lane,
Woking, Surrey.
Tel: (04862) 60268.
Stand 33
Grama (Winter) Ltd,
21b Dryden Chambers,
119, Oxford Street, London, W1.
Tel: 01-636 8210
Stand 46
H B Computers,
22 Newland Street,
Kettering,
Northamptonshire.
Tel: (0536) 839922
Stands 51 and 53
H L Audio Newtronics,
138 Kingsland Road,
London, E2.
Tel: 01-739 1582
Stand 8
A J Harding,
28 Collington Avenue,
Bexhill-on-Sea,
East Sussex,
Tel: (0424) 220391
Stand 55
Keen Computers Ltd,
5 The Poultry,
Nottingham, NG1 2HW,
Tel: (0602) 583254
Stand 44
PRACTICAL COMPUTING July 1979
KES Computers,
4 Summerfields,
Yarnfield,
Stone, Staffs.
Tel: (0785 77) 297:
Stand 54
LP Enterprises,
313, Kingston Road,
Ilford, Essex.
Tel: 01553 1001
Stands 12 and 13
Lyme Peripherals,
2 Avenue Court,
Farm Avenue,
London, NW2.
Tel: 01-425 0490
Stand 7
Midwich Computer Co. Ltd.,
Hillsborough House,
Churchgate Street,
Old Harlow, Essex.
Tel: (0279) 25756
Stand 16
MicroFocus Ltd.,
58 Acacia Road,
London, NW8.
Tel: 01-722 8843
Stand 22
Microsolve Computer Services
Ltd,
252 Hale Lane,
Edgware, Middx.
Tel: 01-958 4347
Stand 10
Nascom Microcomputers,
92 Broad Street,
Chesham, Bucks.
Tel: (02405) 75151
Stand 48
Newtons Laboratories,
123 Wandsworth High Street,
London, SW18.
Tel: 01-870 4248
Stands 38, 39, 40 and 41
a7 20 |
ape
Online Publications,
Cleveland Road,
Uxbridge, Middx.
Tel: (0895) 39262
Stand 35
Osborne & Associates,
PO Box 2036,
Berkeley, CA 84702, USA.
Stand 50
Personal Computers Ltd,
194-200, Bishopsgate,
London, EC2.
Tel: 01-283 3391
Stand 49
Petsoft,
MicroAct Ltd.,
5:6 Vicarage Road,
Edgbaston, Birmingham,
Tel: (0635) 201131/200854
Stand 14
Practical Computing,
30-31 Islington Green,
London, N1.
Tel: 01-359 8451
Stand 17 ;
Research Machines,
209 Cowley Road, Oxford.
Tels (0865) 49791
Stand 30
Rostronics,
118 Wandsworth High Street,
London, SW18,
Tel: 01-660 4805
Stand 31
Sirton Products Ltd,
13 Warwick Road,
Coulsdon, Surrey.
Tel: 01-660 5617
Stand 9
Technalogics,
8 Egerton Street,
Liverpool, L8 7LY,
Merseyside.
Tel: 051-724 2695
Stand 11
Can
What you can see at the Show
Abacus Computers Ltd
62, New Cavendish Street,
London, W1.
Tel: 01-580 8841
Stand 3
ABACUS will be exhibiting two
machines, the TEI and Com-
pucolor. They will run on
standard Cobol packages and
the Compucolor will be
hooked to a graphics terminal
controlled by the TEI.
You will be able to get your
hands on the machines and
there will be sales and techni-
cal staff to take orders and
give free advice.
Byte Shop
426-428, Cranbrook Road,
Gants Hill, Ilford, Essex.
Tel: 01-554 2177
Stands 18, 19, 20, 25, 26, 27
THE Byte Shop, with more
space than anyone else at the
show, will be giving most of its
range an airing. The equip-
ment on show will include the
Cromemco System 3, Proces-
sor Technology Sol-20, North
Star Horizon, the new Pet and
the ITT 2020. There will be
continuous demonstrations of
the machines by experienced
staff.
Two new surprise ranges
will be launched -— a complete
range of Ohio Scientific Super-
boards with 74MB disc drives,
plus a range of equipment
based on the Digital Equip-
ment LSI processor.
CCS Microhire
7, Peartree Dell,
Letchworth, Herts.
Tel: (046 26) 73301
Stand 15
THE COMPANY will be concen-
trating on two aspects — sales
and hire. It will be exhibiting
Pet, Apple II, Exidy Sorcerer
and Compucolor. You will
also have an opportunity to
see the machines running on
CCS software.
The Japanese microcompu-
ter SORD is expected to make
an appearance. Two versions,
the 48K and the 128K, will be
demonstrating colour
graphics, among other things.
Sales and hire transactions
will take place, as well as an
exchange service, so if you
68
want to take your old compu-
ter and swap it for another,
this is the stand to visit.
Comart
PO Box 2,
St. Neots, Huntingdon.
Tel: (0480) 215005
Stand 34
COMART will be exhibiting its
complete range of Cromemco
equipment, along with the
Processor Technology Sol and
the North Star Horizon. All
will be running on standard
packages. It also hopes to be
showing its Microbox.
The stand will be fully-
staffed with sales and technical
people who will be taking
enquiries on sales and passing
them to dealers. An abund-
ance of literature on all sys-
tems will be available.
Commodore Business Systems
360, Euston Road,
London, NW1 3BL.
Tel: 01-388 5702
Stand 21
COMMODORE will be showing
the whole range of Pet mic-
rocomputers and peripherals,
including all the new equip-
ment. A range of its own
software will be running on the
equipment and sales and
technical staff will be on hand
to give demonstrations and
answer questions. The Kim 1
will also be exhibited.
Comp Computer Components
14, Station Road,
Barnet, Herts.
Tel: 01-449 6569
Stands 28 and 29
COMP will launch its new
machine at the show, the
Compukit UK 101, which will
compete directly with the re-
cently announced Nascom-2.
It is a turnkey kit based on the
6502 processor. It has 19K of
memory, 4K of user RAM
expandable to 8K, and a 2K
powerful monitor, 256-
character set and 8K Microsoft
Basic.
It is complete with power
supply, keyboard and RS
modulator, which means that
you can interface it to an
ordinary TV set, giving 48
-but
characters per line. You can
walk away from the show with
one under your arm for £219.
There will be a one-hour
seminar on Saturday after-
noon, given by designer Tony
Burke, to introduce the
machine. Vouchers worth £5
and £10 will be given away and
they can be used towards the
purchase of the U.K. Com-
pukit.
Other hardware on display
will include the new 16K Pet,
Exidy Sorcerer, Apple, TRS-
80, Nascom and Hitachi
monitors. Five to 10 percent
discounts will be given on all
the above.
The stand will be staffed by
the well-informed engineers
who are employed by Comp
for such occasions.
Computabits
41, Vincent Street,
Yeovil, Somerset.
Tel: (0935) 26522
Stand 6
THIS stand will display a range
of standard Pets and Kim-ls,
instead of the normal
peripherals it will be running
with a set of related products
designed by Computabits.
Hopefully, they will include
voice input and output and a
music synthesiser for the Pet.
The Kim-1 will be working
with many of the special pro-
jects featured in Practical
Computing over the last few
months.
Nick Hampshire, Com-
putabits editor of Practical
Computing and manager of the
business, hopes to have his
new book published in time
for sale at the show. It is, he
says, packed with ‘all the
things Commodore doesn’t tell
you”.
The stand will be staffed by
technical people and part of it
will be sublet to Infoguide,
which markets Compusettes
cassette software for the Pet.
Computer Bookshop
Temple House,
43/48, New Street,
Birmingham, B2 4LH.
Tel: (021) 643 4577
Stand 47
COMPUTER BOOKSHOP is a
trade distributor of books,
literature and training courses,
supporting the development of
the microelectronics and per-
sonal computer industry.
Books on display will con-
centrate on the four major
processors — the 6800, 8080,
Z-80 and 6502 and ‘‘will fulfill
the needs of all sections of
hardware users.”
Two new books which will
be on display are Programming
the 6502 by Rodnay Zaks -
recommended by Mike Lake
of the Independent Pet Users’
Group - and Programming a
Microcomputer 6502 by Caxton
Foster. Both titles are applic-
able to Pet and Apple.
Also on display will be a
range of Camelot education
books written specifically for
use in schools and colleges. A
detailed catalogue of all Com-
puter Bookshop titles will be
available.
Datalogic Ltd
29, Marylebone Road,
London, NW1.
Tel: 01-486 7288
Stand 45
THERE is an air of mystery
surrounding the Datalogic
stand, where a new microcom-
puter will be unveiled. All we
could discover about it is that
it is a product of the Datalogic
micrologic division and it has
been described as a ‘‘computer
in a briefcase”’.
It has been designed for a
specific application for a cus-
tomer who has already or-
dered 50 of the machines.
Dillon’s University Bookshop
1, Malet Street,
London, WCI1E 7JB.
Tel: 01-636 1577
Stand 4
ONE of London’s leading
bookshops, Dillon’s will be
exhibiting more than 50 titles
relating to microcomputers
and microprocessors. The
stand will be staffed by
“people who know about the
books’’.
Only one copy of each book
will be on display, so Dillon’s
will be taking orders only.
PRACTICAL COMPUTING July 1979
Distributed Data Processing
Essex House,
Cherrydown, Basildon, Essex.
Tel: (0268) 727474/282155
Stand 5
DpDP will be prodmoting its new
improved large disc drive. It
increases the storage capacity
for the ITT 2020 over its
market competitor, the Apple
IL.
The black and white
monitor for the 2020 will be on
sale at a reduced price, as will
the 16K upgrade kit. DDP also
hopes to have a colour
monitor available.
Electrical Research
Association
Cleeve Road,
Leatherhead, Surrey.
Tel: (03723) 74151
Stand 24
ERA is not exhibiting the usual
equipment models but is con-
centrating on the education
and training side. On display
will be the microprocessor
teaching system, the MP Ex-
perimentor. It was designed
originally as a course for ITT
in West Germany but ERA
has now devised a machine
which it; will market.
Full and detailed coverage
will be given to several experi-
mental and highly-researched
-projects. Perhaps the most
interesting and exciting is that
which looks at the problems of
Microprocessor versus Man
and The Elements.
This fascinating document
looks at the effects of weather
on microprocessors, its reac-
tion to altitude and, arguably
the most exciting of all, the
Physical Destruction Analysis.
Various experiments have
been made in an abundance of
agonising ways, including set-
ting a chip in a plastic encapsu-
lation, boiling it in sulphuric
acid to remove the plastic
covering, then studying the
chip under an electromicro-
scope for faults in all individu-
al sections.
The project also examines
the effects of nuclear weapons
on microprocessors. For ex-
ample, it shows what would
happen to a microprocessor
contained in one of the more
sophisticated armoured vehi-
cles during and after attack.
Equinox Computer Systems
Kleeman House,
16, Anning Street, New Inn
Yard, London, EC2.
Tel: 01-739 2387
Stand 32
EQUINOX will be showing the
Equinox 300 multi-user, multi-
tasking, time-sharing mic-
rocomputer. It serves a mix-
ture of VDUs and printers, as
well as floppy discs, hard discs
and industry-standard tape
drives.
Systems similar have been
installed in several businesses,
educational establishments
and laboratories. The system
has a powerful operating
system, including Basic, Lisp,
Pascal and Snobol 4, together
with a multiple-pass macro-
assembler with linking loader
and screen-orientated text
processor and editor.
Equinox will also be show-
ing the Horizon Z-80A-based
system.
Eurocale Ltd
55, High Holborn,
London, W1.
Tel: 01-405 3113/3223
Stands 1 and 2
EURO-CALC, the shop which
sells anything with a chip in it,
will be exhibiting a new mic-
rocomputer which it feels will
cause one of the biggest stirs of
the show.
The machine is Plessey-
made, built exclusively for
Euro-Calc and entirely in Eng-
land. It can be used as a stand-
alone unit or as a program
development system.
Euro-Calc will also be dis-
playing its usual brands, in-
cluding Pet, Apple, ITT 2020
and some printers.
Gemsoft Ltd
Alverstone Lodge,
Wych Hill Lane, Woking,
Surrey.
Tel: (04862) 60268
Stand 33
GEMSOFT will be displaying
some 70 games for, computer
and television and you can see
PRACTICAL COMPUTING July 1979
some of them running on the
Pet. It also hopes to have two
business packages available
which it is now hurriedly
writing.
It has also developed a
sound effects board for games.
Grama (Winter) Ltd
21B, Dryden Chambers,
119, Oxford Street, London,
Wi.
Tel: 01-636 8210
Stand 46
GRAMA will have a full range
of Pet and SWTPC hardware
on view. It will be demonstrat-
ing, its own software package,
BUs(iness) 1, which is a com-
plete package comprising 23
options and 30 programs
stored on 10 files.
Tony Winter, owner of the
firm and author of the pack-
age, reckons it to be in adv-
ance of anything he has so far
seen and values it at more than
£1,000. He is offering it at
£275 plus VAT.
For the duration of the show
any firm order for a system
worth more than £3,200, in-
‘cluding disc and printer,
placed at the exhibition will
include BUs(iness) 1 free.
A.J. Harding
28 Collington Avenue,
Bexhill-on-Sea, East Sussex.
Tel: (0424) 220391
Stand 55
THE TRS-80 is the main attrac-
tion, particularly as the new
Level Three will be introduced
for the first time.
The new Monitor Three
program will make its debut.
The Library 100 model will be
on show on a demonstration
machine.
H B Computers
22 Newland Street,
Kettering, Northamptonshire.
Tel: (0536) 83922
Stands 51 and 53
PETS, Exidy Sorcerers and
Apple IIs are the attractions
with some possible but so far
unspecified releases. Filling
the shelves will be TV inter-
faces, sound boxes, Pertec.
floppy discs, and a series of
new interfaces.
H L Audio Newtronics
138, Kingsland Road,
London, E2
Tel: 01-739 1582
Stand 8
THE MAIN feature will be the
Elf II kit. Associated
hardware includes the giant
board kit, 4K static RAM
board, ASCII keyboard,
power supplies, modulators,
light pen and steel cabinets.
Software available includes
Tiny Basic on cassette, and
Elf-Bug monitor on cassette.
Manuals will also be on sale.
Keen Computers Ltd
5, The Poultry
Nottingham.
Tel: (0602) 583254
Stand 44
THIS dealer will be displaying
various pieces of software
which turn the Apple II into a
business, educational or home
enthusiasts’ machine. The
Keen range of software is wide
and covers all major commer-
cial uses. Titles include Incom-
plete Record Accounting,
Word Processing and Informa-
tion Retrieval.
A variety of statistical and
mathematical software will
also be available, as will the
range of memory upgrade. kits
for the Apple II, ITT 2020 and
Tandy TRS-80.
A selection of printer and
display terminals suitable for
use with the Apple and other
micros will be on view, such as
the Eledex DP 8000, Cen-
tronics 779 and Diablo 1610.
Keen is one of six dealers
for the Attaché microcompu-
ter which will be filling the rest
of the shelves on the stand.
Kes Computers
4 Summerfields,
Yarnfield, Staffs. ST15 ORH
Tel: (0785) 77297
Stand 54
KES COMPUTERS will be show-
ing an Ohio Superboard with
(Continued on page 71)
‘69
Buy a System. . .Not just a “Pretty Box”
The SD System* — From about 97p per hour (40-hour week)
*The SD System Includes::
SDS-200 Microcomputer
T.I. 810 Printer (or Equivalent)
The SDS-200 TOTAL System features:
System Hardware
The SDS-200 give you features that are not found in systems
costing thousands more. State-of-the-Art Engineering. Quality
Production and Full Reliability testing make the SDS-200 a
dependable, compact and easy to operate data processing
system.
@Up to 256K Bytes RAM
@Fuil Keyboard with Special Accounting Key Pad
@Large 12 in. Video Display Screen
@Full Cursor Control including Addressable Cursor
®@Blinking, Underlining, Reverse and Protected Fields
@Uses 8 in. Flexible Diskettes for Permanent Storage 2 Mbyte on-line
@Forward and Reverse Scrolling
@Capable of up to 160 Special 'Characters
@Expandable with Memory and Peripheral Equipment
@Will Operate as a Remote Batch Processor for Large Systems
System Software
A full range of Business Programs are available from CAP-CPP
written in Microcobol.
The system will support all normal high level languages
including :—
Fortran
Cobol
Basic
CP/M
A Total System
SD Systems knows that small
businesses do not keep full-time
programmers on staff. We also know
that individually designed business
programs can be expensive on a one-
time basis. That is why we offer the
SDS-200 and compatible business
software.
Complete Software
SD Systems Business Software is a
complete system package that
includes everything from general
ledger, payroll and inventory control
to Cash Receipts and Mailing List.
Special modifications can be made to
fit your specific needs.
Leasing Available
The SDS-200 is available by leasing.
This gives the small business the
opportunity to select the method of
acquisition that best fits their needs.
SYSmeEMS
SDS-200 Expandable
The SDS-200 is designed in a manner
to give you expansion capabilities. As
your needs change the computer
system that you select today should
be able to change with you. By the
addition of memory and peripheral
equipment, the SDS-200 can expand
to fit your needs.
U.K. DISTRIBUTOR:
AIRAMCO LTD
Unit A2, 9 Longford Avenue, Kilwinning Ind. Est.,
Kilwinning, Ayrshire KA13 6EX
(0294) 57755
Dealer enquiries invited
70
Telex 779808
@ Circle No. 172
PRACTICAL COMPUTING. July 1979
What you can see at the Show
(Continued from Page 69)
C24P mini-disk and a new
packaged single-board compu-
ter based on the Ohio 500
board. This is 8K Basic using
an RS 232C interface or 20
milliamp loop serial interface -
other standards can be met for
various terminals.
The Pet User Board Serial
Interface will also be on
display.
Kes also offers computer
systems consultancy to tailor
systems for customers.
LP Enterprises
313, Kingston Road,
Ilford, Essex. IG1 1PJ
Tel: 01-553 1001
Stands 12, 13
LP ENTERPRISES will show its
range of books and magazines.
The company handles sub-
scriptions for American per-
sonal computing magazines, as
well as holding a large selec-
tion of books on nearly all the
professional, business and
hobbyist computing topics.
Examples include books on
introduction to micros, busi-
ness programs in Basic, the
artist and the computer, and
pocket guides for program-
mers. New publications will be
available from Scelby, Byte
Publications, Sybex, Sams and
Creative Computing Press.
LP Enterprises specialises in
distributing microcomputer
software on diskette and cas-
sette, including CP/M operat-
ing system, Basic, Fortran
compilers and business
software such as stock control,
sales ledger/purchase ledger
(accounts payable/receivable)
and general ledger. They are.
available for popular makes of
8080, Z-80 and 8085 proces-
sors.
Lyme Peripherals Ltd
2, Avenue Court,
Farm Avenue, London NW2.
Tel: 01-452 0490
Stand 7
LYME PERIPHERALS will have
its full range of VDUs on
display. For the first time, it
will be featuring the Lyme
4003 VDU: It incorporates all
the features available on the
4002, with the added advan-
-tage that it is compatible with
the Digital Equipment VTS2.
Lyme was due to merge with
James Scott of Glasgow, a firm
specialising in keyboards for
the IBM 3270, which may also
be on view.
Microfocus Ltd
58, Acacia Road,
London, NW8.
Tei: 01-722 8843
Stand 22
THIS software and systems
house will be demonstrating its
CIS Cobol Compilation
System which runs on 8080
and Z-80 processors. The
software will be running on the
Intel MDS-800 and the
Tandberg TDV range of intel-
ligent desk-top terminals.
A new variant of CIS Cobol
will be launched at the show.
Microsolve Computer Services
Ltd
125-129, High Street,
Edgware, Middlesex. HA8
THF
Tel: 01-951 0218
Stand 10
MICROSOLVE will be showing
Apple II with a new printer,
the Printerm Model 879,
which is one of the new gener-
ation of low-cost printers with
a speed of 120 cps. Software
consists of debtors’ ledger,
invoicing, medical billing and
case history, financial model-
ling and payroll. There is also
a school physics and com-
merce teaching package.
Also being exhibited will-be
a new computer, the Micro
Star 45 with 64K RAM. It is a
multi-user, multi-task compu-
ter starting at £5,000 and can
be used by up to three simul-
taneous users. It will support a
double-sided floppy disc drive
with an option for double
density.
Among the software it con-
tains is a full word processing
package, a purchase and deb-
tors’ ledger and stock con-
trol. The printer will be the
‘PRACTICAL COMPUTING July 1979.
new Qume Sprint 5, a daisy-
wheel printer terminal with
typewriter quality for word
processing.
Midwich Computer Co Ltd
Hillsborough House,
Churchgate Street,
Old Harlow, Essex.
Tel: (0279) 25756
Stand 16
THE Hardware Co changed its
name recently to the Midwich
Computer Co. The new name
is being accompanied by a new
range of microcomputers
which will be given their first
public airing.
The computers are of Italian,
design, from SGS-ATES. The
modular microcomputers are
based on the Z-80 CPU and
are aimed at the education
market.
The lowest-level machine is
the Nenocomputer System. It
uses a ‘‘calculator-style’’,
hand-held hexadecimal data
input display station and a
solderless experimental bread-
board station with binary data
input display for digital experi-
ments.
They are combined to
enable the student to design
and study complete microcom-
puter systems using Z-80,
PIO, CTC and MOS memory.
The computers are provided
with training books which take
the student through funda-
mental computer basics to the
most complex Z-80 program-
ming.
Nascom Microcomputers
92, Broad Street,
Chesham, Bucks.
Tel: (02405) 75151
Stand 48
ACCORDING to Nascom, “‘one
of the most interesting new
products of the show will be
seen,” the Nascom-2, featur-
ing 20K of memory, 8K Mic-
rosoft Basic and an ‘‘incom-
parable” 2K monitor.
On show with the Nascom-2
will be the Nascom-1 and all its
add-ons, including a memory
board and Vero frame. The
latter will accept the Nascom-2
as well. Other new products
are expected to be available.
Newtons Laboratories
PO Box 789,
127, Wandsworth High Street,
London, SW18.
Tel: 01-870 4248
Stands 38, 39, 40, 41
THIS FIRM is one of several
distributors of the Alpha
Micro System, claimed to be
the most powerful and ver-
satile micro system available.
It supports eight floppy discs,
four hard discs or any combi-
nation of both. Memory
ranges from 64KB to about
1.02 MB.
The system is based on
AMOS (Alpha Micro Operat-
ing System) which is a multi-
user, multi-tasking, time-
‘sharing operating system
which includes job priorities
and a command language in-
terpreter.
Printers and other peripher-
als will be available from
stock.
Online Conferences Ltd
Cleveland Road,
Uxbridge, Middlesex.
Tel: (08995) 39262
Stand 35
ONLINE specialises in the co-
ordination of conferences and
exhibitions in the fields of
information processing and
communications technologies.
All the events are related
directly to practical commer-
cial considerations and many
highlight trends in technology
which have important social
implications.
The Microcomputer Show is
an obvious example, as is
Viewdata °80. This event is
scheduled for next Spring at
Wembley Conference Centre
and will investigate the use of
the television screen as an
information access device.
The proceedings of most of
the conferences have been
published and form the most
comprehensive range of books
on computer communications
and technologies available.
Online publications has tre-
bled its sales over the last year
and is adding continually to its
publications titles.
(Continued on page 75)
71
DYNABYTE COMPUTERS
ARE ALL BUSINESS
INSIDE AND OUT.
When we designed our new small
business computers, we meant busi-
ness.
As basic as that seems, it is unique.
Just about every other microcomputer
being sold as a small business system
today was originally designed as a kit
for hobbyists.
Every design decision was made
with quality and reliability in mind. The
result is dependable performance and a
solid appearance for business, profes-
sional and scientific applications.
FIRST SMALL SYSTEM WITH
BIG SYSTEM STORAGE
Many applications handle large
quantities of information, so the DB8/2
uses two quad density 5-inch disk
drives with our exclusive Dual Density
Disk Controller for up to 1.2 megabytes
of formatted storage. That’s more
capacity than two single density 8-inch
drives.
If you need more storage, our
DB8/4 has two 8-inch drives with up to
2 megabytes capacity, more than any
other dual floppy disk system on the
market.
OUR SOFTWARE IS
BIG ON BUSINESS
Dynabyte helps you get down to
business immediately. The DB8/2 is the
first microcomputer to offer enough
storage capacity on 5-inch drives to
fully utilize CP/M,* the most widely
accepted disk operating system. We
also supply and support BASIC, FOR-
* CP/M is a trademark of Digital Research.
Associates to Dynabyte, Inc. U.S.A.
Regional Distributors:
TRAN and COBOL programming lan-
guages, Our applications packages in-
clude general ledger, accounts receiv-
able, word processing and many other
CP/M compatible programs.
Reliability is a big consideration in
buying a business computer, so we built
it in. Our edge connectors meet military
specifications, the toughest electronics
manufacturing standard. Our regulated
power supply is designed to meet U.L.
standards, which means the entire sys-
tem runs cool and dependable. And our
cast aluminum enclosures are rugged as
well as attractive.
AND THE BIGGEST
THING OF ALL
Customer support. Our support
starts at the factory with testing and
bum-in programs that assure the entire
integrated system is reliable prior to
shipment. Our completely modular de-
sign allows continuing support in the
field. We maintain a bonded inventory
of all sub-system modules which means
we can deliver replacement sub-
assemblies overnight nearly anywhere
in the U.K.
Dynabyte built in little things, too.
Like a _ fully-populated 12-slot
backplane, switched AC outlets for ac-
cessories, an option for European
power, quiet whisper fans with long-life
metal construction, lighted indicator
switches for Power On and Halt, a
shielded enclosure to protect disk drives
from electro-mechanical interference,
and a fully enclosed power supply for
operator safety.
Since we didn’t cut comers in de.
sign, the price/performance ratios of
our systems make good business sense.
THE INSIDE FACTS
The DB8/2 Computer System in-
cludes two 5S-inch disk drives either
single or double sided for up to 1.2
megabytes of mass storage; a 4MHz
Z-80 processing module with one
parallel and two serial ports, 32k of
RAM, a 12-slot fully-populated back-
plane; our exclusive Dual Density
Disk Controller, and CP/M.
The DB8/1 Computer includes a
4MHz Z-80 processor with one parallel
and two serial I/O ports, 32k RAM,
and a 12-slot fully-populated back-
plane.
The DB8/4 Disk System, designed
to be the mass storage companion to the
DB8/1, includes two 8-inch floppy disk
drives in either single or double sided
configuration for up to 2 megabytes of
mass storage, our Dual Density Disk
Controller, and CP/M.
All three units will be available in
rack mount models.
For a descriptive brochure and
price list, call or write Dynabyte UK/
Europe, 25 Park Rd, Scarborough,
Yorks, England. Phone: 0723-65559.
Or better yet, see your local dealer.
DINABYTE
YOU CAN DEPEND ON IT.
Merseyside: Zytel 2 Alexander Drive, Heswall. 051-342 4443
Brookfield Drive, Aintree. 051-523 4011.
Other regions available. Contact Mark Proudfoot.
@ Circle No. 173
PRACTICAL COMPUTING July 1979
pynaBytTE
Pes
Rib.
NewBear
©
Computing Store Ltd.
- Newbear DB80 Printer
ex-stock £595
serial & parallel ports
optional extra - 64 Key ASCII keyboard
Introducing - Newbear 700
low cost VDU ex-stock £299
V24 interface upper case only
keyboard and monitor available separately
Sym I - 6502 based micro from Synertek -
Fully assembled and tested
~ Down in price now only £160
Now in stock BASF 5% ins. disc drives.
Horizon (S100 bus Z80 based micro)
16K RAM with single disc drive £1265
32K RAM with double disc drive
With 2 Serial and 2 parallel port £1983
Newbear now stocks O.K. tools.
24
HOUR
DELIVERY"
IN MOST
CASES
Ail prices subject to 8% VAT.
Carriage by arrangement.
Barclaycard and Access welcome.
Minimum official order £10.
Callers welcome Mon-Sat 9.00- 5.30
but please phone us first on 0635 30505
Visit our Northern Office at 2A Gatley Road.
Cheadle. Cheshire. Tel: 061-491-2290.
All mail order to Newbury.
APY) fe
oa =<. Schugart SA400 5% ins.
&( & disc drives down to £190
Our new address is Newbear Computing Ltd,
40 Bartholomew Street, Newbury, Berks.
@ Circle No. 174
COMPUTER FIELD MAINTENANCE
Keeps Horizon running smoothly
Keeps Cromemco running smoothly
Keeps Abacus running smoothly
Keeps SWTP running smoothly
Keeps Rair running smoothly
Keeping things running smoothly
Computer Field Maintenance
A CWT company, a Member of the IAL Group,
Excell House, Trust Industrial Estate, Wilbury Way
Hitchin, HertsSG40UZ _
Tel: (0462) 51511 Telex: 826649
@ Circle No. 175
74 PRACTICAL COMPUTING July 1979
What you can see at the Show
(Continued from page 71)
On display will be more
than 60 titles, as well as a
range of forward conference
literature. One of the world-
wide best séllers is Personal
Computers in Business and a
new title Introduction to Mic-
rocomputers is .expected to
have record sales,
Osborne & Assoc.
PO Box 2036,
Berkeley CA 84702
ULS.A. ;
Tel: 0101-415 548 2805
Stand 50
THIS publishing house . and
consultancy will have all its
titles on show, including An
Introduction to Microcomput-
ing, A Program for Logic
Design, Assembly Language
Programming, and Business
Book.
Adam Osborne, who is also
playing a major role as a
speaker at the seminar, and
Georgette Psarias will be
present.
Personal Computers Ltd
194/200, Bishopsgate,
London, EC2.
Tel: 01-283 3391
Stand 49:
PERSONAL COMPUTERS is one
of the leading Apple II dis-
tributors, with 20 dealers
throughout the country. The
show is the ideal opportunity
for it to exhibit its range of
Apple hardware and as it runs
the Apple software bank, you
should have the opportunity to
see some interesting programs
at work.
Petsoft
5/6, Vicarage Road,
Edgbaston, Birmingham.
Tel: (0635) 201131/200854
Stand 14
PETSOFT will‘have a complete
program supermarket at the
show, comprising the “widest
range of software available for
microcomputers in the world”.
Two hundred titles will be
there, ranging from account-
ing at £350 on disc to chicken
recipes at £3 on cassette.
Petsoft will be launching a
new range of business
software, collectively called
PETACT. The range, Petsoft
says, “‘is the first microcompu-
ter software written by a main-
frame team to mainframe stan-
dards.”
There will be several Pets on
the stand, demonstrating vari-
ous pieces of software.
Practical Computing
30-31, Islington Green,
London, N1.
Tel: 01-359-8451
Stand 17
THE 1979 Microcomputer
Show marks the first anniver-
sary of Practical Computing
which was launched last year
at the Do-it-Yourself Show,-
immediately selling-out that
first edition.
The magazine is heavily in-
volved once more with the
show, producing the official
Showguide which will be distri-
buted from a stand in the hotel
foyer, as well as devoting
seven pages to it in this, our
latest and biggest edition.
Practical Computing will be
selling al) issues dating from
October, 1978, as well as our
highly-successful Computer
Guides and the invaluable
Checklist for Data Processing.
You will also have the chance
of an introduction to our big
sister, WHICH COMPUTER?
We will be taking subscrip-
tions for both magazines and
answering questions or solving
any problems you may have.
Don’t miss this opportunity to
meet the staff of Britain’s
number one microcomputer
magazine.
Research Machines
PO Box 75,
Chapel Street, Oxford.
Tel: (0865) 49792
Stand 30
RESEARCH MACHINES will be
demonstrating its British-built
Research Machines 380-Z mic-
rocomputer. This ‘general-
PRACTICAL COMPUTING July 7979
purpose computer is offered in
several versions, ranging from
16K RAM and single- or dual-
cassette recorder backing
store, to the top of the range
with 56K RAM and dual full-
size floppy disc drive (one
megabyte on-line storage).
New or recent items on
display will be a high-
resolution graphics/memory
add-on board, text processing
software in use with the 380-Z
and a daisywheel printer, and
the new operating system ex-
tension, which also allows the
use of a conventional VDU
with the 380-Z.
Other software demons-
trated will include the RML
Interactive Text Editor with
Immediate Mode Editing, ex-
tended Disc Basic, Cobol,
Fortran IV, Algol, and Termi-
nal Mode Software. Those
interested in Z-80 program
development or microproces-
sor training should ask for a
demonstration of the 380-Z
software front panel.
Rostronics
118, Wandsworth High Street,
London, SW18
Tel: 01-660 4805
Stand 31
ROSTRONICS, the Wandsworth
shop specialising in TRS-80
business systems, promises a
crowded stand. The Multiwri-
ter 3, “the ultimate daisy-
wheel’’, will be demonstrated
as part of the Rostronics word
‘processing system. The Mul-
tiwriter 3 is bi-directional, with
full graphics capability, inter-
changeable print wheels, fore-
ign language character sets,
and is fully programmable.
Rostronics has been buying
and testing chips and will be
selling its own memory expan-
sion kits.
Another own-brand exhibit
will be the Rostronics system
desk, which can be tailor-
made for any system.
Available only on the stand
will be the first issue of the
British TRS-80 newsletter,
which is bound to cause a
queue.
Also on display will be the
Rostronics small business
system and appropriate
software, as well as many
books.
Sirton Products Ltd
13, Warwick Road,
Coulsdon, Surrey.
Tel: 01-660 5617
Stand 9
SIRTON is a dealer for SD
Systems, Jade, Ithaca-Audio
and Intergrand, and can
obtain boards from many
other U.S. manufacturers at
competitive prices. It will be
exhibiting its range of S100
boards, including three CPU
boards and comprising many
stock items.
The Sirton Data Prepara-
tion Unit will be exhibited for
the first time. It is an integral
unit with a keyboard, 20-
character alphanumeric dis-
play and 2K RAM for data
storage. The unit is
microprocessor-controlled,
has a text-editing facility and
can transmit and receive data
via an RS232 or 20 milliAmp
serial data link.
Another new product is the
Sirton single-board computer,
featuring on-board 2K RAM,
1 or 2K ROM, serial I/O and
16 data-in and data-out lines.
It is designed for dedicated
control applications or intelli-
gent interfaces.
Keyboards, VDUs and vari-
ous disc-orientated packages
will also be displayed.
Technalogics
8, Egerton Street,
Liverpool. L8 7LY,
Merseyside.
Tel: 051-724 2695
Stand 11
TECHNALOGICS will feature its
TECS computer system and
demonstrate Teletext recep-
tion, its computing facilities,
and Prestel. The TECS com-
puter system will be available
in kit form as well as ready-
built.
Technalogics will also be
demonstrating pattern and
colour bar generators — port-
able, battery-powered TV
units for the amateur and TV
service engineer.
It will also be showing a full
Prestel editing terminal aimed
at the information providers of
Prestel.
75
TO START our series on U.K. microcomputer manufacturers,
Kay Floyd visited Hertfordshire to meet Nascom Microcompu-
ters, one of the top British companies. Its Nascom-1 kit has been
a runaway success, selling more than 12,000 units in the last 18
months.
Kay spoke to Kerr Borland, marketing manager of Nascom
_Microcomputers and a director of the parent company,
electronics distributor Nasco. Although he and John Marshall,
chairman and managing director, are the brains behind
Nascom, Borland describes himself as a ‘‘gofer’’ — at the top
level, of course.
What prompted you to start Nascom?
I was managing director of Nasco at the
time and Nascom was given to me as a
kind of project. It took off because of the
microcomputer revolution. John Mar-
shall and I were very interested in
everything that was going on and because
Nasco had been distributing semiconduc-
tor products for nearly 10 years, we knew
what it was about.
What role did Nasco play setting up’
Nascom?
There is a definite division between
Nasco and Nascom, though Nasco gave
us financial support at the beginning. The
Nasco group includes Lynx Electronics
and one or two other companies; Nascom
Microcomputers is within that structure.
When Nascom was first set up we
decimated Nasco and Lynx because I
took all the staff I wanted with me. Only
recently have we re-staffed them with
managers and clerical people. We are
now re-structuring Lynx and are about to
open a new store in Amersham, which
will offer a vast range of products for
people who want to build microcompu-
ters.
Two-man design
Who designed the Nascom-1?
John Marshall and myself. We wanted
to see if we could make a small micro-
computer. We had the ideas for the
design but couldn’t carry them out
ourselves. We telephoned several people
and did some market research but that
wasn’t much help as we found that there
was really no existing market for the type
of product we had in mind.
When we said that it had to be built for
less then £200 they said it couldn’t be
done. Finally we went to Chris Shelton of
Shelton Instruments. A top microcompu-
ter engineer, he put our plan into
practice. Now. 18 months later, we have
the top-selling single-board computer in
the U.K.
When was the Nascom-1 launched?
Officially, in January, 1978; that makes
it one of the oldest microcomputers. We
started delivering the following March.
What was the initial response?
By the end of the day of the launch we
had more than 300 units ordered, and
paid for, and we still didn’t have a
working machine to show anyone. That
76
was followed by around 7,000 letters
from people wanting to buy or know
more about it.
The Post Office wasn’t very pleased at
having to sort and deliver that kind of
mail in a rural backwater. It took us ages
to plough through them but we managed
to turn around a lot of the enquiries.
When we Started, no-one could foresee
what a success it would be.
Distributors
How many distributors do you have?
We have 12 in the U.K. Some are
multiple companies, so there are more
retail outlets than that implies. Then
there are seven main distributors abroad.
In Germany, we have between 15 and 20
retail outlets.
Many of our components are from
Nasco and through the semiconductor
industry in the U.S. Because of these
problems there are no Nascoms for sale
in France at the moment. We can never
supply enough.
Where is your manufacturing plant?
In Chesham. We are looking at a site in
the U.S. and two others in the U.K.
There are 25 people working there, out of
around 50 in the company. We hope to
increase the number in our manufactur-
ing facility to between 80 and 100 within
| the next two years.
| How reliable is the machine?
Very few of our kits or boards are ever
| returned to us. We have two repair
| engineers and that’s all we need. They
can manage to turn them around within a
week,
What do you see as the company aim in
the immediate future?
We shall end up selling built systems.
Everything we sell is in kit form now but
our overseas customers want everything
built. Because we can’t do it at the
moment, they are prepared to build their
own.
What was the thinking behind the recently-
launched Nascom-2? ,
In no way is the Nascom-2 a replace-
ment for the Nascom-1. Over the 18-
month period it became obvious that
there is a market for the Nascom-1 for the
foreseeable future. There is also a large
market, however, for an upgrade version
which will have more of a computing
bias. Many of the additions necessary to
The rev
started |
the Nascom-1 are integral to the Nascom-
2.
Do you have an in-house design team or
do you contract that work?
By the end of this year we aim to have
one of the most complete design teams
anyone has to offer in this field. We will
not be aiming at an end result - a
packaged machine. What we want to do
is to produce a board with as much
flexibility as possible.
As long as we stay with the standard
components, this machine will do any-
thing. Since the first was built in 1977, no
component has been changed. There are
some very good design houses around
and we expect to be among them. in the
next five years.
Do you do much software development?
We do a reasonable amount, mainly in
high-level languages and monitors. We
get a good deal of material sent to us. We
have developed an 8K Basic, Cobol and
Pascal - that sort of thing. There are
other standard packages which we would
buy rather than develop ourselves.
How much have you spent on research and
development?
So far, we have spent only £150,000 but
next year it will be £500,000 or more. It is
low at the moment because we have been
sending a good deal of work outside the
company. We have seven engineers, all
specialists in their own right, who design
our boards. We are attracting them
because we are doing original research.
We will have plenty of new things at the
end of the year.
Turnover
What is the company turnover this year?
The estimated turnover from June,
1978 to June, 1979 is £1.5 million. That’s
in our first year of trading. We estimate
that it will be £5 million next year.
How do you see the company as a whole?
I think we are the only British micro-
computer company. No-one has any
chance of getting close to us. No-one is
doing the research we are. We produce
microcomputer boards - that’s the
market we see and we understand it.
We do more than just selling packages.
Our competition in Europe is nil but
that’s all going to change.
How do you see the company’s future?
We are producing microcomputer
boards —- that’s the market we see for
ourselves. We feel that the Nascom-1 is
only half our range and that there’s a
huge market for our complete computer
boards.
Obviously, we shall expand very rapid-
PRACTICAL COMPUTING July 1979
lll
ylution
ly. We are already looking for more
manufacturing space and. we are increas-
ing our product range all the time. By the
end of 1979 we hope to have one of the
most complete design teams of anyone in
this field.
We want to be the country’s top
microcomputer designer and manufac-
| turer, and the way things are going, that
day will not be far away.
Our main overseas distributor is in
Sweden, where the Nascom-1 has been
accepted well. In fact, more than 70
| percent of our output goes to Europe.
How many Nascoms have you sold?
So far we’ve sold 12,000 units world-
wide. Last year we delivered 6,000 and in
1979 we estimate that we will ship 14,000.
The problem is that we can’t make them
fast enough to satisfy all our customers.
If we could make 500 a week we could
sell them with no difficulty, Shortly we
hope to be manufacturing 500 Nascom-1s
a month and that inevitably will increase.
Marketing
What is your marketing strategy?
We are badly constricted on the mar-
keting side and we have cut our market-
ing budget because we do not need to
advertise — we have no reason to push our
product very heavily. We are swamped
with orders, can’t get the components fast
enough, and we can’t produce the
machines fast enough.
We are looking for a sales manager but
he won’t have any selling to do; he will
| have to explain to people why orders are |
late being delivered and that we can’t |
possibly appoint more distributors for the
time being. Three Far East companies
want to take distributorships but there’s
no way we can do that, either. The saving
grace of the Nascom-1 is its good value,
which shows itself in expanding purch-
ases.
What are the main market areas for the
Nascom-1?
The Nascom-1 was created as an
industrial board. In the beginning it
wasn’t fully socketed for various reasons;
now it is, so we can add plenty of PCBs
and extra chips. We found then that the
biggest market area was the industrial
user and the hobbyist.
It began as a hobbyist machine but now
we sell most to industry, with the rest of
our production split between the hobbyist
and educational establishments. It is very
popular with schools and we will be
selling a case for the boards to comply
with school safety regulations.
The biggest market we see for Nascom-
PRACTICAL COMPUTING July 1979
Kerr Borland.
1 is definitely a board market and we see
a huge market for our complete computer
boards. OEMs are already buying them
and building their own configurations
around them.
Six or seven people are producing end-
products based on our machine — not
necessarily computer products but some-
thing totally different, where the compu-
ter has played a vital role in production.
In many cases people have built ma-
chines and ask us for 50 boards a month
for a specific project on which they are |
working. Big OEMs order them in their
thousands for just one project — we have
two customers like that. The Nascom-1 is
becoming a standard component for
many development systems.
We feel that the market area for it will
be in expansion boards which make it
more acceptable for people who want to |
use it as a development system to look at
a Z-80-based machine. Soon we shall
have graphics and a disc controller, too.
It is a low-cost but powerful system,
especially attractive for OEMs who want
to interface it to other things.
To what do you attribute the success of the
machine?
Nascom success is undoubtedly due to
our use of the -Z-80 processor. Many
suppliers have given us a great deal of
help as well, especially Mostek, which
supplies our processors.
Parts problem
Why have you had problems supplying the
Nascom-1?
One major problem is that you can’t
get the bits. No-one in the chip manufac-
turing business realised the sheer volume
we were going to use. The industry goes
through a four-year cycle of boom and
disaster. At the moment, we are coming
out of a disaster period, hence the lack of
parts.
The determining factor of the cycle is
the U.S. markets. Forget the Japanese.
The Americans assess their cost produc-
tion and work schedules on their home
market; the overseas market is just an
extra to them.
If the home market expands, they
forget the outside business and we go
short of parts. We try to buy as much of
the product as we can in the U:S., but we
have to get our high-technology parts
from the U.S. because they are not made
in this country.
(contd. on page 79)
77
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78 PRACTICAL COMPUTING July 1979
Nascom-z2 prototype
THE long-awaited Nascom-2 was launched in April and has
emerged, not as a replacement for the Nascom-1, but as an
upgrade version which will have more of a computing bias.
It is based on the Z-80A processor — theoretically twice as
fast as the Z-80 - with an 8-bit CPU. The hardware consists of
a 12in. x 8in. card with all bus lines fully buffered to the
Nasbus specification. There is 20K of on-board addressable
memory which is made up of 2K Monitor, 1K video RAM, 1K
work space/user RAM, 8K Microsoft Basic and 8K static
RAM.
It has a new expanded keyboard built specially for Nascom,
which uses standard Nascom monitor-controlled decoding.
The new machine uses 8K Basic which offers a high degree
of compatibility with other system’ and programs published in
magazines and books should run under Nascom 8K Basic with
little or no modification. The language will also run on the
Nascom-1.
One of the most exciting features of the Nascom-2 is its
ability to run with a completely new monitor which has been
designed specially for it.
Called Nas-sys I, it incorporates all the features of the
Nasbug 2K monitor with many additional functions. It uses a
blinking, non-destructive cursor, with on-screen editing. The
method of calling routines has been modified and rationalised
so that users need only a two-byte RST operation.
It was designed originally to run with the new keyboard but
can be used with the Nascom-1 keyboard by using combina-
tions of keys.
ASCII terminals are fully-supported via the serial interface
and users can addtheir own I/O drivers via the Nas-sys /O
driver table to support other devices. Forty-two user-
accessible RST operations are provided.
The Nascom-2 will cost £295 plus VAT and deliveries will
start this month. Two OEMs have already placed orders for
the machines and Nascom says ‘‘We will satisfy the demands
of the U.K. market first.”
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79
—
“CVMAYAROLDO,
Historical simulation
AT FIRST SIGHT it might seem far-fetched
to use the computer to assist in historical
simulations in the classroom of a com-
prehensive school but I have been brood-
ing on the variety of ideas involved over a
period of at least 10 years.
During my own sojourn in a VIth form
I became interested in the links between
the disciplines. A scholarship to Mas-
sachusetts gave me the chance to learn
Basic and an introduction to Probability
Richard Ennals writes about the ideas which won top prize in the
schools section of our Christmas competition. The entry was from
the history and computer studies departments of Sweyne School,
Rayleigh, Essex. Ennals is developing some of his history
simulations on the Research Machines 380-Z he won.
Later, at Cambridge, I spent a year
immersed in the linguistic philosophy of
Wittgenstein, especially his theories of
games and languages. My studies in-
and Decision Theory.
HOW THE IDEAS WORK
cluded mathematical logic before I
Our use of the computer for history simulations on a set of principles from the
classroom teaching situation:
@ The logical structure of a computer analogue of a historical situation is similar to the
80
equivalent classroom simulation, with the possible difference that the simulation
game normally involves decisions by a number of participants rather than by a single
player. So it should be feasible to make use of the computer analogue to enhance the
classroom simulation, and vice versa.
If the appropriate programming and role preparation are provided in advance, the
input of data and classroom role-play can be carried-out without over-direction from
the teacher.
The computer can aid the simulation participants in carrying-out historically credible
decisions, given the accuracy of information already stored.
There is philosophically a clear link between mathematical and computer logic,
language structure and the rules of games — as outlined, for instance in
Wittgenstein’s Philosophical Investigations and Braithwaite’s Theory of Games as a
tool for the Moral Philospher). This has clear, if undeveloped, practical implications,
especially for people like teachers who have the task of explaining complex
processes.
The computer should not be used simply for its own sake of so doing, and it should
not perform functions already carried-out adequately by other means. It should help
clarify the decision processes involved and enhance the learning experience of the
class. It should enable the participants to be aware of irrelation of two or more
variables, and the consequences of their combination—hard to convey by
conventional means.
The computer work involved in class should not be too complex, with easily-
understood input data and comprehensible conclusions printed-out or displayed on a
screen.
switched to a history degree.
While a student, I wrote and produced
a number of plays on historical situations,
all starting from the basis of simulation
and role-play. Teacher training followed
and on teaching practice in Southfields, I
developed my first simulation ‘kit’, based
on the United Nations Organisation and
how its members handle a series of
possible crises.
Based on briefing
My first teaching post, in Mitcham, was
in a department whose head, John
Waddleton, had considerable skill and
experience in simulations; this produced
further kits on the House of Commons
and the workings of a factory.
No computer facilities were available
for these; the simulations were based on
the briefing of the individuals, and the
free development of the situation by the
group in their roles.
Last September, in my present post as
head of the history department at Sweyne
School, I found an ideal opportunity to
develop my ideas further. My colleague,
Martin Frampton, shared my interest in
games, and I developed a range of new
PRACTICAL COMPUTING July 1979
kits based on the Russian Revolution, the
Age of Discovery, the Wedgwood firm in
the Industrial Revolution, the Norman
Conquest, and the League of Nations—
all for mixed-ability classes.
Next to my classroom at Sweyne is the
computer studies room, run by John
Ward. I showed him a range of programs
I had devised for use in the games; he
detailed three able ‘O’ level students—
Andrew Wood, Martin Attwood and
Keith Stewart—to help me as part of
their computer studies course-work.
They came to history lessons where the
games were being used, and devised
programs to facilitate the simulation
process and enhance the students’ under-
standing.
In an evening
Then Ward spotted the competition
run by Practical Computing. The initial
entry was written in an evening but a
good deal of hard work was put in by all
five of the team in developing the ideas,
flowcharts and programs for the final
submission, which ran to about 40 pages
of typescript.
We have had to work so far with
strictly limited access to a time-sharing
terminal on-line to the county computer
centre but our students have enthusiasm
to start work at 7.30 each morning.
Helpful to all
The prize of a Research Machines 380-
Z should expand our ability enormously
to produce innovative materials for use
with our classes, and in other schools.
Essex County Council has been en-
PRACTICAL COMPUTING July 1979
couraging computer education for some
years and recommends the 380-Z. It is
helping us to modify our rooms to gain
the most advantage from this new acquis-
ition for our two departments.
Use of a television screen should
enable a whole class, rather than just one
individual, to benefit from the output of
‘the computer; and the aim in our
historical work is for the computer to
become a major classroom teaching aid.
Practical Computing and Research
Machines have given us a chance to show
how this can be done.
PUTTING THE PRINCIPLES INTO PRACTICE
Some examples of how the computer can be of use, based
on classroom experience with simulation materials de-
vised at Sweyne School.
@ Wedgwood Potteries
we use a simulation kit for third-year, mixed-ability secondary students based on
Josiah Wedgwood and his pottery firm in the 18th century. Class members are
allotted a separate role among the people connected with the Wedgwood Pottery.
Each receives a historical briefing on an individual part so that decisions wilt be
historically authentic. A range of Basic programs has been developed to aid the
management in planning of wages, prices and research policy. Data input is
straightforward, and the printed conclusions go beyond the complexity of reasoning
and the calculation of which the students are capable. Participants react to the
computer findings, and the game continues. This relies, in part, on simple economic
theory and, in part, on the provision of historically-accurate background material.
Explorers
Second-year, mixed-ability history students have been using a simulation kit based on
the Voyages of Discovery in the 15th and 16th centuries; the results have been very
encouraging in terms of historical authenticity, the quality of written work and the
level of enthusiastic participation. A fifth-year student, Andrew Wood, has written a
program which clarifies the process of trading and makes possible many of the
authentic variations in commodities and prices. Further programs will clarify the
choices between routes, and their consequences, and enable the ‘explorers’ better to
plan their strategies in the light of detailed historical knowledge.
Russian Revolution
Two fifth-year students, Keith Stewart and Martin Attwood, have devised a program
based on decision theory to analyse the choices facing a Russian revolutionary in
1917. This will enhance the effectiveness of our existing fourth-year simulation kit for
the Revolution. As with the other kits, each member of the class is allotted a different
role through whose eyes they see the events of 1917 as they unfold. Properly used,
the computer can enhance the authenticity of the simulation and throw the decision
involved into sharper focus, so that a complex historical situation can be brought to
life in the classroom.
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London
TLC World Trading Ltd
01-839-3893
Sumlock Bondain Ltd
011-253-2447
Da Vilai Computers Ltd
011-202-9630
Manchester
Cytek (UK) Ltd
061-832-7604
Sumlock Electronic Sves.
061-228-3507
Morley (W. Yorks)
Yorkshire Electronic Svcs.
0532-522181
Newport
G. R. Electronics-Ltd
0633-67426
Northern Ireland
Medical & Scientific
08462-77533
Nottingham
Betos (Systems) Ltd
0602-48108
Reading
C.S.E. (Computers)
0734-61492
Southampton
Symtec Systems Ltd
0703-37731
Business Electronics
0703-738248
Swansea
Radio Supplies (Swansea)
0792-24140
Thame, Oxon
Memec Systems Ltd
084-421-3149
Woking
Petalece Led
048-62-69032
Yeovil
Computerbits Ltd
0935-26522
In case of difficulty call COMMODORE SYSTEMS DIVISION
360 Euston Road, London. Tel. 01-388-5
@ Circle No. 178
PRACTICAL COMPUTING July 1979
Do you want fo buy
a MicroComputer?
Digitus stocks a wide selection of micros
and provides expert advice, sizing and
design.
Test some robust, proven computers:
@ Apple 11
@® Cromemco
@ DG MicroNova
@ North Star Horizon
@ Processor Technology SOL
@ Exidy Sorcerer
Choose from a range of peripherals:
Shugart, North Star, Sanyo, Sony, Lear
Siegler, Cifer, Centronics, Teletype.
Discuss and select a system to fit your
present and future needs.
PS Also provided:
micro Skill, software, books and training.
Call, write or visit:
Digitus Ltd
Dumbarton House
68 Oxford Street
London W1
Tel: 01-636 0105
- Do you need help
to design and process
your MicroSystems?
Through its MicroSkill Register of over
200 professionals, Digitus provides
experienced programmers, designers
and engineers to develop systems on
most micros including:
@ Z80/8080 @® LSI 11
@ 6502 @ MicroNova
@ 6800
Some of the Register people have their
own machines. Others work on customer
or Digitus equipment.
Whether you require a small program
written or a large system designed and
engineered, Digitus MicroSkill can
provide support.
BS o
Call, write or visit:
Digitus Ltd
Dumbarton House
68 Oxford Street
London W1
Tel: 01-636 0105
PS Applications to join the Register
are welcomed, Please send C.V.
and two professional references.
PRACTICAL COMPUTING July 1979
Does your
MicroComputer
need software?
Digitus supplies application programs,
systems, and tailormade software
systems.
We specialise in business and
administration programs for Z80/8080
and MicroNova computers including:
@ Wordprocessing
@ Mailing
@ Sales Ledger
@ Purchase Ledger
@ Nominal Ledger
@ Stock Control
Also supplied: systems software for
Z80/8080 including CP/M, Extended
Basic, Fortran and Interactive Cobol.
Go Ss - :
Call, write or visit:
Digitus Ltd
Dumbarton House
68 Oxford Street
London W1
Tel: 01-636 0105
Bo you want a
MicroSolution for
your business?
Some people want to buy equipment and
software and bolt it together for
themselves.
Others want to buy a Solution, a complete
system to meet their needs economically
and reliably.
Digitus provides MicroSolutions for
business, administration and
professional practices.
We analyse your requirements, specify
systems, choose Suitable equipment and
software, tailor it to fit your people and
organisation, hold hands during
transition, train operators and managers,
arrange regular maintenance and
support.
In short, provide a total MicroSolution.
£ & —
Call, write or visit:
Digitus Ltd
[ Dumbarton House
: 68 Oxford Street
London W1
Tel: 01-636 0105
@ Circle No. 179
83
|Cramped
Man Eater
Cassette for Commodore Pet only. Avail-
able from Games Workshop, 1 Dalling
Road, Hammersmith, London W6 ODJ
Tel: 01-741 3445 Price, £4.
HAVING seen some of the other offerings |
from Games Workshop, I found this a |
little disappointing. The idea behind the
game is reasonable and the method of
playing looks to be well-designed but the
layout of the board ruins what might have
been a good game.
The aim is to surround a shark with a |
set of swimmers so that it cannot move
and eat a swimmer. As the shark can eat
only diagonally and move orthogonally — |
up, down, right or left - this seems easy. |
The problem is that the shark is visible
only at the beginning and when it has just
eaten a swimmer. Any two men can be
moved in one turn by using the grid
reference system on the board.
It is there that the main criticism
applies. The board is cramped into the
top lefthand corner of the screen and is
much too small for comfort. I found I was
having to squint to decide exactly where
my swimmer was and where I was moving
him. As the rest of the board was used
only to display prompts and error mes-
sages, I found this rather irritating. Even
more annoying was the fact that if you
entered a move and pressed ‘‘return” —
the “return” not being needed — it moved
your man and then displayed ‘“Co-
ordinate not on the board”’.
I feel this game could be good but it
would take a major re-think of the layout
and more careful programming.—K.F.
FileHandling __
Cassette for Tandy TRS-80. Manufac-
tured by Circle Enterprises Inc., Box 546,
Groton, CT 06340.
THIS PROGRAM is very easy to operate
and spells-out everything for you, taking
only minutes to learn. Perhaps its simplic-
ity is its greatest drawback because,
despite its name, it is little more than a
telephone book.
It has the capacity for 100 entries per
file and the information you can put on
each file is name, address, telephone
number and birthday. We found that the |
last item was in most cases unnecessary
but could be useful for, say, a small
insurance firm.
The program begins by giving a menu
of five options — input data, list names in
file, search/edit, record on cassette and
exit from program. You punch the |
corresponding number to each of these
functions, from 0-4.
The input data allows you to create
files; listing names in the file gives the
subjects in alphabetical order with tele-
84
phone numbers; the search/edit facility
gives several options. You can select the
next or previous name in the file to the
| one you may already have chosen, search
| for the file by pressing the first letter or
two of the surname.
Easy editing
Editing is easy. All you do is select the
relevant file and take the line number to
be edited, type in the whole line at the
top of the screen with the correction,
press the enter key, and all is done.
Finally, by using the delete function you
can erase anyone from your file com-
pletely.
It is unfortunate that the program will
not identify a file by anything other than
the surname of the person. If you forgot
the name probably you would have to run
through more than 50 entries to find it.
The program is very fast for putting a |
different format on to the screen and
| response times are a point in its favour.
Sorting the names automatically into
alphabetical order is another plus for the
| program.
A handy piece of software if you want
to record names and telephone numbers
but not much use if you want a file with a
great deal of detail on it.—K.F.
Space Fighter
Cassette for Tandy TRS-80, by A. J.
Harding. Available from most Tandy
| dealers. Price: £9.95.
YET another program to take you into the
outer galactic regions, this time as a space
fighter pilot. You meet five enemy ships
and when they are in laser sights, you
shoot them down,
You determine how many missiles you
have to fire and there are three levels of
play which you also choose. There is no
time limit on the game, which is a pity, as
this type of game lends itself to beating
the clock.
Loses appeal
When you hit a ship the screen goes
into a rather elaborate explosion simula-
}
| number of missiles remaining. When you
| many shots you had left. If you use all
| little more of the competition element
Android Nim
| robots shrieking when they-are about to
| excluding the controllers which appear at
| eliminated. All you have to do is press
_ the same fashion that it is your turn.
Cassette software mum
tion. Then the sequence starts again and
the ship moves slowly from the left into
your sights. By the way, you can destroy
a ship only if you hit it on the nose -
nowhere else counts.
The bottom of the screen displays how
many ships you have destroyed and the
have eliminated all the ships, the compu-
ter congratulates you and tells you how
your missiles without destroying the
enemy, you are advised to abandon ship.
Unfortunately, once you have mas-
tered the technique of destroying the
ships — after about half an hour’s play -
the game quickly loses its appeal. If a
had been included with say, a clock or
faster-moving ships, it would have been
more enjoyable.—K.F.
Cassette for Tandy TRS-80. Manufac-
tured by 80-US Software, PO Box 7112,
Tacoma, Washington, U.S.A.
ANDROID NIM is based on all the other
Nim games but with a difference — this
one has sound and excellently-produced
graphic robots.
All you need to do to receive the sound |
is plug-in the cord which goes to the |
AUX of your cassette recorder into any
audio amplifier and you will hear the
be eliminated, and also the sound of the
laser which takes them off the screen.
The idea is to remove the last Android,
the left of the screen. There is one for
each of the three rows of Androids to be
the number of the row - the top row is |
one — and then the number of Androids |
you wish to eliminate.
Reminder
You have the choice of whether to start |
or allow the computer to start and your
turn is indicated by a flashing display and
sound. If you wait 45 seconds without
making a move, you will be reminded in
The graphics were truly excellent on
this tape but the response time was |
agonisingly slow. Once you had keyed-in
your move all the Androids would move
their heads one by one to look at the poor |
victim who was about to be zapped. This |
took a long time and was very infuriating.
The worst thing about the program is
that we couldn’t win. Time and again we
tried, even following the pattern of the
computer during its last game, but it was
impossible.
If you have two hours to spare and you
manage to beat the Android execution-
ers, let us know — we would like to know
how it’s done.—K.F.
@ Circle No. 180
PRACTICAL COMPUTING July 7979
If you buy the wrong
personal computer,
you cant re-program your
bank account!
Buying a personal computer is not an easy task.
So many people selling them neglect the little things that enable you
to get the most from your computer, such as documentation, spares, add-ons and
maintenance. We believe that these ‘details’ are essential. We are the only British company
to put all our time and energy into the personal computer market and are in the best
position to advise you on your initial purchase and keep you fully
informed about all the new developments relevant to your computer.
Personal Computers Limited — the name of the game.
Exclusive to Personal Computers Ltd.
German Apple II. Available shortly.
Say ‘hello’ to a graphics Apple Il A business Apple II
Dersona
Computers
Limited
IRAIR NAC K 1]
BLACK BOX MICROCOMPUTER
8G
ALLUSTRATIRGCHBASIC:
( GAESIMPLE BPROLCRAMMINC BLARCOACL®)
WE CONTINUE our
series of articles on how
to program in Basic, g
probably the most =
widely-used :
programming language .
for small computers. |
For the series, we have
obtained the serialisation
rights for one of the best
\S OMPONENTS OF THE LANGUAGE
[PREFACE
books on the subject, C
5; % ae A NPUT & OUTPUT EXPRESSIONS AND FUNCTIONS
Illustrating Basic by at) 3. Q .
Donald Alcock.
a Be & ontroe
* = Gen
Each month, we are a
publishing a partofthe =| _ ao GA Reays
book, so by the end of the
series you will have the
complete book. It is ¥ 3. MA Pane?
written with a distinct
informality and has a
rather unusual So @ OMPLETE EXAMPLE PROGRAMS
4 ° it 7 - C MCDXCII <@ ILLUSTRATING A SYMBOL- STATE TABLE
presentation; but it sb this BEST WAY HOME « ILLUSTRATING A ROUTE-FINDING METHOD
style, we believe, which
makes it one of the most —
-to- i a
easy-to-read tutorials. =], eons np otewine ok
*
Alcock Illustrating Basic.
Chapter 2. © Cambridge *
University Press. :
Reprinted by permission.
_
8. (% ies oF pata
§) ro) 8 YNTAX
NDEx
Geer @ Circle No. 181
PRACTICAL COMPUTING July 1979
39
59
a)
10]
102
106
11h
NS
127
132
87
A PROGRAM TO CONVERT
ROMAN TO MORE FAMILIAR
NUMBERS.
THIS EXAMPLE DEMONSTRATES THE USE OF A SYMBOL-SJATE TABLE
s@ A STANDARD YJOOL IN PROGRAMMING <&
ASSUME ALL VALID ROMAN NUMBERS ARE COMPOSED OF THE
FOLLOWING ELEMENTS < NEVER MORE THAN ONE FROM EACH
CONSECUTIVE BOX 3
6 a7; $5
M=1000 ® 100 DC=600 X=10 LX=60 T= 1 VI=6
MM =2000 CC=200 DCC = 700) XX=20 LXX=70 W=2 Vai= 7
MMM = = 3000 CCC= 300 DCCC= B00 | XXX= 30 LXXX= 80.) LII=3 VIII=8
‘ARBITRARY UPPER LIMIT D=A4CO CM=900 = XC = 90 {Ve Ix=
C35 CLO LCS CD=4 XL=40 4 X=9
QT SEEMS CLASSICAL ROME SELDOM USED THE SUB7RACT/VE PRINCIPLE
INHERENT IN IV . PREFERRING IIIT , BUT THIS PROGRAM REFUSES To
HANDLE MORE THAN THREE CONSECUTIVE LETTERS OF THE SAME KIND »))
sie LOGIC OF THE PROGRAM 1S CONTAINED IN THE FOLLOWING
SYMBOL- STATE TABLE 3
“ syMBOL”
vy |t
Ma
(STARTING —_ =
Grrr $807| 1&1
a 5207/18 tt
“ STATE ”
7 AKE THE ROMAN NUMBER CIX AS AN EXAMPLE 2 BEGIN WITH A YALUE
OF ZERO» YOU ARE IN STATE OL Q@ WHERE THE ARROW IS 2 SO LOOK
DOWN FROM SYMBOL C AND FIND 100&09 WHICH SAYS “ADD 100 TO
THE VALUE & CHANGE S$7A7TF TO. 093 SO ADD 100 TO ZERO & MOVE
THE ARROW TO 09. NOW LOOK DOWN FROM SYMBOL I AND FIND
12113 SO ADD {4 TO THE VALUE @1oori=10{) & MOVE THE ARROW TO
STATE {1 FINALLY LOOK DOWN FROM SYMBOL X AND FIND 8%008 SO
ADD 8 TO THE VALUE G101+8=109)o THE.0O MEANS YOUVE FINISHED o
6Z6L A497 ONILNdWOD TVOILOVYd
ILLUSTRATING BASIC Pace 102
CHAPTER
Rie TABLE IS PART OF THE COMPUTER PROGRAM AND PREPARED. AS
SHOWN BELOWe TO SAVE SPACE EACH ELEMENT OF A(,) 1S MADE TO
CONTAIN BOTH THE NUMBER TO BE ADDED AND THE NUMBER OF THE
NEW. STATE <#% THUS 5&O7 BECOMES 10045 +07 = 5074 THE
ENTRIES SAYING “ERROR” ARE ENTERED AS -1,
{0 REM DECODE ROMAN NUMERALS
20 DIM A(it,7), C(7)
30 REM EACH ELEMENT =100*ADDITION + NEWSTATE
100 REM M, D, Cc, (Ss x Nae OL
{10 DATA 100002, 50003, 10009, 5005, 1010, 507, 114
120 DATA 100002, 50003, 10009, 5005, 1010, 507, 111
130 DATA =t, -1, 10009; 5005, 1010, 507, 111
140. DATA =, -!, 10004, 5005, 1010, 507, 111
150 DATA =4, -1, —{, 5006, 1010, 507, 111
460 DATA -t, -4, -4, —1, 1006, 507, 114
470 DATA ={, “4, ~1, ~{, -t, 508, 111
{80 DATA = =f =(5 —1, <-{, il, 108
190 DATA 80005, 30005, 10004, 5006, 1010, 508, 111
200 DATA ~f; “1, 8007, 3007; 1006, 508, 14!
210 DATA ~ty —}, —t, —1, 800, 300, 108
220 REM
} 230 MAT READ A(tf,7)
H 240 DATA "Mm", fp? ‘a. Ae , aye Ry.t
| 250 READ c$(1), c$(2), C$(3)5 C$(4), CH(5), C$(6), C$(7)
260 REM
ee ee oe
Yo TEXTUAL ARRAY C#() IS NOW LIKE THIS3
CHL) C$(2)_ C$(3) c$(a) C$(5) Cc$(e) C$(7)
I (a) Sa be Nees itn]
IDEALLY WE SHOULD NOW “INPUT” A SINGLE TEXT LIKE “MCDXCLI”
AND EXTRACT ITS LETTERS ONE BY ONE FOR MATCHING IN ARRAY
C$( )o UNFORTUNATELY BASICS
CAN*®T AGREE HOW TO DO IT.
SUPPOSE YOU HAD THIS TEXT $
LET P$ = "FRUSTRATION “
& WANTED TO PUT "RAT" INTO A$ $
HERE ARE JUST SOME WAYS TO DO TT,
LET A$= SUBSTR(P4, 6 3)
LET A$=P$ (6,8)
LET A$=5TR(P$, 6,3)
LET A$=MID(P$, 6%, 3%)
EXTRACT THE N™ LESTER
OF TEXT AND STORE /T
TH
iS T$ =CB(K) 7?
fi, iY ad je LET A$=EXxT$(P$,6,8)
he, UMBER 0. = g
ERROR: MO MATCH roo eo ae
: eA LET A£=SUBE (PE, 6,3)
SO WE SHALL BE CONTENT TO “INPUT” LETTERS ONE BY ONE <y SEE OVERLEAF o
ILLUSTRATING BASIC PAGE {03
68
6261 ANF ONILAdWOD 1VOILOVYd
CHAPTER 6}
talere IS THE MAIN BODY OF THE PROGRAM FOR DECODING ROMAN
NUMERALS $
et ———— _—-- oe UN Sey
| 300 REM MAIN PROGRAM STARTS
| 310 PRINT "TYPE ROMAN NUMBERS LETTER BY LETTER”
| 320 PRINT "END NUMBERS WITH * END RUN WITH #6"
330 PRINT "NUMBERS ENDING IV & IX NEED NO * ”
' 340 PRINT
350 PRINT EEE) age
360 LET R=1 eS TRCLE
370 LET M=O ah Wi 8)
j 380 LET C=0 TSP IDENTICAL cOnsELUTIVE
8 i - NF eRe vious LETTER
410 IF TS = "**" THEN 610
420 IF T= “*" THEN 580
430 FOR K=1 707
440 IF T$=C$(K) THEN 480
450 NEXT kK
460 PRINT "CRAZY ROMAN NUMBER“
470 GOTO 340 NEW START. as eae
480 LET x= A(R,K) Getnl Gas
' 490 IF X<O THEN 460
' 500 REM ENSURE ONLY 3 OCCURRENCES OF ANY 1 LETTER
510 LET C= (1- ABS(SGN(K-P)))* (14+C) <qed ZF PREVIOUS‘. ‘CuRRENT”
| 52 1F c>2 THEN #60 OI De.
530 LET P=kK ci 367 “MRE VEX” To. CuRenT”
| S40 REM ACCUMULATE RESULT IN M3 CHANGE STATE R
550 LET M=M+INT(X/ 100) <b ist Prat oF eLEMENT )
560 LET R=X-1004INT(X/{00) <a 2 mere mew sare >
570 IF R <> O THEN 400 ge ae
580 REM PRINT THE RESULT eRe,
590 PRINT M
600 GO TO 340 <wG new gracr)
610 END
RUN
“2001
TYPE ROMAN NUMBERS LETTER BY LETTER
END
KUMBERS ENDING “IV & IX NEED NO'*
START
2M
2m
cea
2
NUMBERS WITH * END RUN WITH ®*
ILLUSTRATING BASIC PAGE 10g
CHAPTER 6)
~ Yeni. ™
ly NO * BECAUSE
NUMBER ENDS
IN IV
a i i a
A ENO OF RUN
AR THiS EXAMPLE THE FIRST PART OF EACH ELEMENT OF THE
SYMBOL-STATE TABLE IS SIMPLY A NUMBER TO BE ADDED INTO
VARIABLE **M", IN MORE SERIOUS APPLICATIONS THIS WOULD BE
THE LINE NUMBER OF A SUBROUTINE o AFTER PICKING UP AN
ELEMENT Q@ AS AT LINE ABOD THERE WOULD BE AN “ON”
INSTRUCTION CAUSING A JUMP TO THE PARTICULAR SUBROUTINE
SELECTED BY THAT ELEMENT. AFTER RETURNING FROM THE
SUBROUTINE THERE WOULD BE AN INSTRUCTION CAUSING A
CHANGE OF STATE JUST AS THAT ON LINE 560 y
ILLUSTRATING BASIC PAGE ]O5
06
6261 ANF ONILNdWOD TWOILOVud
CHAPTER 67
A PROBLEM
COMMON TO
INDUSTRY AND
: , COMMERCE o
HERE IS AN EXAMPLE OF AN “*ALGORITHM’” (@ COMPUTER JARGON FOR
“METHOD” }) BY WHICH YOU CAN TRACE THE QUICKEST ROUTE
THROUGH A NETWORK OF “NODES” AND “EDGES".4 (& ANOTHER
APPLICATION OF THE TECHNIQUE SHOWN IS “CRITICAL-PATH ANALYSIS "9 )
THIS ALGORITHM WORKS AS LONG AS-THERE IS NO MORE THAN ONE EDGE
IN ONE DIRECTION BETWEEN ANY TWO NODES o
O
MS Time To
: TRAVEL ALONG
THIS EDGE
ie HOW. IT WORKS, YOU KEEP “TRACK OF THINGS AS’ SHOWN IN
THE SKETCH BELOW FOR NODE 2
af i —<2), 3)
BUS, { © | 4 [6-0 |
SS OE
OF NODE2
‘See AT NODE 3. VISIT EACH NODE IN TURN & 3, 4,5,6,
CONTINUING ROUND AGAIN & 1,2,3,4,5,6,1,2, etc. UNTIL
ALL THE “SWITCHES” ARE “OFF”, AT EACH NODE DO THE FOLLOWING
gee AS DESCRIBED FOR NODE 2 3
XH LOOK AT THE SWITCH IN A(2,1)o IF THIS IS “OFF” THEN GO
ON TO THE NEXT NODE. IF (tT 15 “ON” THEN?
xe PICK UP THE BEST TIME SO FAR THIS IS IN A(2,2)0
sk USE THE HEAD OF CHAIN IN A(2,4) To START LOOKING AT
ALL NODES RUNNING OUT OF NODE 24 FOR EACH LINK
IN THE CHAIN DO THE THINGS DESCRIBED. BELOW WITH
SPECIFIC REFERENCE TO NODE 5 8
ILLUSTRATING BASIC Pace 106
a
| a 3 —_ CHAPTER
yx PICK UP THE NODE NUMBER @ INITIALLY THIS 16-5 Do
wv PICK UP THE TIME TO TRAVEL ALONG THE EDGE TO
THAT NODE Q@ INITIALLY 8-0 } AND ADD THIS To THE
TIME ALREADY PICKED UP FROM A(2,2) TO GIVE T$
(THE TIME TO REACH NODE 5 VIA NODE 2) a
™& CONSULT A(5,2) TO SEE IF YOU HAVE JUST FOUND A
BETTER ROUTE. IF SO3
@ SWITCH MON” AT A551) 6
@ REPLACE OLD BEST TIME A(5,2) WITH To
@ PUT NODE NUMBER 2 INTO A(S,3) THUS
BUILDING A CHAIN THROUGH NODES ON THE
BEST ROUTE o
ae ave COMPLETED WORK AT EACH NODE . SW/7CH OFF THAT NODE,
oe A(,) & B(,) MUST BE PREPARED BEFORE WORKING ROUND
THE NODES AS DESCRIBED ABOVE, ALL THE SWITCHES MUST BE
SWITCHED ON > SOME IMPOSSIBLY HIGH JOURNEY TIMES PUT INTO
THE SECOND COLUMN OF A(,), AND EVERY NODE MUST BE. LINKED
TO THE NODES RUNNING OUT OF IT. THE JOURNEY TIME TO THE
STARTING NODE MUST BE SET TO ZERO,
10 REM QUICKEST WAY HOME: DEMONSTRATE ALGORITHM ONLY
20 REM (DATA NOT -CHECKED FOR ABSURODITIES)
30 REM ALLOW FOR SO KODES AND 120 EDGES
40 DIM A(50,4), B(1i20, 3)
50 PRINT "NO.OF NODES, NO.OF EDGES, START NODE, HOME NODE"
60 INPUT N, E, Si) H
70 FOR I= 1 TON :
@O LET A(1,1) = 1 dag Be!
. | 90 LET A(1,2) = 1000000 <ad VERY Wiew rime)
a 100 LET 6A(T,3) = 0 NOS CLEAR WEADS >
' $10 LET A(t,4) = 0 oat B ROUTE CHAIN
: 120 NEXT I ,
ee _ aggre eae
OR THE PROBLEM ILLUSTRATED OPROSITE THE FIRST LINE OF INPUT
DATA WOULD BES 2 6, 9, 3,6 AND ARRAY A(,) WOULD BECOMES
eg
ILLUSTRATING BASIC PAGE 107
6Z6L AINE = ONILAdWOD WOILOVed
CHAPTER 6}
yx PICK UP THE NODE NUMBER INITIALLY THIS 18 5 D.
wr PICK UP THE TIME TO TRAVEL ALONG THE EDGE TO
THAT NODE (INITIALLY 8-0 2 AND ADD THIS To TRE
TIME ALREADY PICKED UP FROM A(2,2) TO GIVE T3
{THE TIME TO REACH NODE 5 VIA NODE 2)o
™% CONSULT A(5,2) To SEE IF YOU HAVE JUST FOUND A
BETTER ROUTE, IF SOS
e switch “ON” AT ALl5,.
@ REPLACE OLD BEST TIME A(5,2) WITH T
@ PUT NODE NUMBER 2 INTO A(5,3) THUS
BUILDING A CHAIN THROUGH NODES ON THE
BEST ROUTE o
es nee COMPLETED WORK AT EACH NODE. 5 SWITCH OFF THAT NODE,
EM Ser AC,) & B(,) MUST BE PREPARED 8&FORE WORKING ROUND
THE NODES AS DESCRIBED ABOVE, ALL THE SWITCHES MUST BE
SWITCHED ON , SOME IMPOSSIBLY HIGH JOURNEY TIMES PUT INTO
THE SECOND COLUMN OF A(,), AND EVERY NODE MUST BE LINKED
TO THE NODES RUNNING OUT OF IT. THE JOURNEY TIME TO THE
STARTING NODE MUST BE SET TO ZERO,
10 REM QUICKEST WAY HOME: DEMONSTRATE ALGORITHM ONLY
20 REM (DATA NOT CHECKED FOR ABSURDITIES)
30 REM ALLOW FOR 50 NODES AND 120 EDGES
40 DIM A(50,4), B(120, 3)
50 PRINT "NO.OF NODES, NO.OF EDGES, START NODE, HOME NODE"
60 INPUT N, E, S, H
TO FOR T= 1 TON aw
GO LET A(I,{i) = 1 Sie ON
a
90 LET A(I,2) = 1000000 <a VERY Wien Time)
100 LET A(I,3) =0
WP CLEAR NEADS
110 LET A(L,4) = 0 b Fae
{20 WEXT I
[Por TWE PROBLEM [ILLUSTRATED OPPOSITE THE FIRST LINE OF INPUT
DATA WOULD BE2 2? 6, 9, 3,6 AND ARRAY A(,) WOULD BECOMES
i wie 4)
JLLUSTRATING Basic PAGE 108
cues 6;
Laden: IS THE MAIN PART OF THE PROGRAM, VARIABLE K COUNTS
THE NUMBER OF TIMES NODE 1 {5 PASSED WHILST CYCLING THROUGH
THE NODES, BUT K IS SET BACK TO ZERO IF A CHANGE IS MADE
TO THE ROUTE, THUS WHEN K GETS TO 2 ALL SWITCHES ARE OFF
AND THE SOLUTION CAN BE PRINTED,
LEY I=S
GO TO 320
LET L=@=L+i
LET rel
LET K=K+1 «oR
IF K> 41 THEN 440
REM
IF A(I,1)=0 THEN 250 acre
LET J = A(1,4)
IF J=< O THEN 420
LET K= 0 I ELCLIID,
LET T = A(I,2) + B(J,3) Sle ele
LET Le= B(3,2) VIA NODE I
IF ACL,2) < T THEN 4
LET ACL,4) = 1 CGultew ow yooe LD
CET ACL) 2) eo
LET A(L,3) =< 1 ADD LINK To _ROUIE CHAIN
Let J =eeC3, 1)
IF J <> O THEN 340
LET A(I,1) =o
GO TO 250
REM PRINT RESULT
PRINT "QUICKEST WAY FROM";S3"TO"3H; "TAKES; A(H,2)3 "THRU"
PRINT Hj
LET X= A(H,3) <q HOME LINK OF ROUTE CHAIN )
LF X=0O THEN 520
PRINT X3
LET X = A(X,3)
GO TO AsO
PRINT
END
—_ THIS PROGRAM WITH THE DATA SHOWN OPPOSITE PRODUCES
THE RESULT 3
QUICKEST WAY FROM 3 TO © TAKES 31 THRU
Oweaee, 1) So
AT THE END OF A RUN THE SECOND COLUMN OF A(,) STORES THE
QUICKEST TIMES FROM NODE S TO ALL OTHER NODES !N THE
NETWORK o
ILLUSTRATING Basic PAGE 109
92
i,
| (4 Cromemco System Three
The professional microcomputer
- At MicroCentre we're supplying the
finest microcomputer at the fairest
price inthe UK.
Our Cromemco System Three boasts
all the features you would expect ina
system designed for professional
users. Features like the fast Z-80A
chip; the flexible S-100 bus; 64K
memory as standard (expandable to
16 MB); 512K dual 8” discs
(expandable to 23 MB with hard
discs); and CDOS—Cromemco’'s
powerful disc operating system,
compatible with CP/M.
Yet it costs just £3786* from
MicroCentre. We can even arrange
maintenance at your premises. And
we'll supply all the software you're
likely to need—Cobol, Fortran,
extended Basic, Word Processing,
Data Base Management, etc
Outstanding value at £65 each—
only from MicroCentre.
Write or call today for our full colour
brochure.
Micro Centre telephone: 031.225 2022
Complete Micro Systems Ltd.
132 St. Stephen St., Edinburgh EH3 5AA
National maintenance can be arranged through CFM Ltd. *Prices exclude VAT and delivery
@ Circle No. 182
PRACTICALCOMPUTING July 1979
SSS Se
Introducing
Communications
Protocols
| by Logica; published by NCC
Publications, 1978; AS, 83
| pages (softback); £5.50
LOGICA is one of the top UK
consultancies and its speciality |
is data communications; both
are good qualifications for a
compact and fact-filled intro-
duction like this.
The book begins by provid-
ing the background to the
growth of communication
needs. It lays great emphasis
on the fact that good computer
systems should not grow but
| should allow for possible ex-
pansion and connection into
sophisticated networks. That
probably doesn’t apply to the
smaller system but if you’re
investing a six-figure sum you
ought to bear it in mind.
Although many data trans-
mission techniques exist, the
underlying principles dictating
protocol requirements are
always similar and must in-
clude message format and pro-
tocol procedures so that a
meaningful dialogue can
ensue.
Security aspects
The protocol must also
ensure that the security as-
pects are dealt with properly
and so the book describes
vertical redundancy checks,
dancy checking.
There is a brief discussion of
the major protocols available
including the IBM, SNA and
the Digital Equipment
ticular use is a section on the
new European standard X25
protocol for public switched
networks. Although not a de-
finitive guide to X25, Logica
manages to provide a useful
overview which should be a
solid basis to further research.
The book also provides an
extensive glossary and bibliog-
raphy which should enable the
| reader quickly to supplement
these areas of special interest.
The book suffers from
having been written, one as-
sumes, by a variety of people
in a hurry, and consequently
proceeds in jumps and starts,
but the information contained
in its few pages are of immense
practical use.
block checks and cyclic redun- |
from computer manufacturers, |
DECnet architectures. Of par- |
Conclusion
@ An extremely useful and
well-written book, low on
waffle and high on information
content, and geared to the
computing professional who
needs to grasp the concepts and
need for communications pro-
tocols quickly.
Cheap Video
Cookbook
by Don Lancaster; published
1978 by Howard W. Sams -
handled here by Prentice Hall
International; AS paperback,
256 pages; £6.55.
ANOTHER Offering from Lan-
caster, this time not so cheap
but certainly informative and,
as always, well-written. Lan-
caster has the kind of en-
thusiasm so often lacking in
technical texts.
Cheap Video Cookbook is
something of a departure from
his familiar Cookbook series
on RTL, TTL and CMOS in
that it’s the first to cover a
Video
Cookbook
by DON LANCASTER
|
7
specific microprocessor appli-
cation — and, indeed, a par-
ticular hobby microcomputer
kit, the Kim-1.
Briefly, the text explains the
theory behind the construction
of an add-on module for the
Kim-1 which provides charac-
ter and graphics displays on a
suitably-modified TV set.
Comprehensive
The book divides easily into
four parts, the first expound-
ing the advantages of a
microprocessor-based ap-
proach and explaining two
special design concepts, the
upstream tap — a means of
allowing the graphics software
to access central memory -
and the SCAN micro instruc-
tion, which ensures high-speed
output of generated charac-
ters.
There’s a comprehensive
section on designing and prog-
PRACTICAL COMPUTING July 1979
ramming the necessary
software, for which you’ll need
| a fairly good knowledge of the
architecture and instruction
set of the 6502. Following that
Lancaster has a “getting-it-
together’’ chapter on
| hardware which won’t tax your
brain too much.
Lastly, he offers a short
section on transparency utilis-
ing spare processor time to run
a user’s program. This is
rather disappointing, as it
hints at what to do instead of
describing any specific trans-
parency techniques; still, it is
but a minor complaint.
There are two potential pit-
falls for the U.K. reader using
this Stateside book. One is at
| the components level. In a
| sense the book is a construc-
tion manual, so you'll need the
| chips — two are rather special-
ised — and the American-made
PCB. Another is the problem
of adapting the design ideas
for other microprocessors
more popular with British-
based kit manufacturers, not-
ably the Zilog Z-80, as used
for the Nascom.
Drive and humour
In fact, for various reasons,
your reviewer is convinced
| that the Z-80 is the only
microprocessor other than
those from the 6800/6502
family which could easily sup-
port the suggested design. The
display (TV set) will also need
modification, which is curious
since it would have been easy
to add-in a UHF modulator to
| the basic design.
Don’t be deterred, though.
The book is a veritable mine of
| information and it is written
with the kind of drive and
| humour one doesn’t find in
corresponding British texts.
Mercifully, it’s also free of
the kind of condescending
writing which seems so much
in vogue nowadays. All credit
to Lancaster for realising that
we don’t need to be told, yet
again, how dynamic RAM
works — how refreshing.
Conclusion
@ A specialist book and cer-
tainly not for the software
pundit. You’ll need to be very
practical to get the most from
the text, but the technical
aspects are so well presented
and the writing so persuasive
that I defy you not to take up
your soldering iron and work.
| should be possible to say from
Do-It-Yourself
Computing
Compiled and edited by Martin
Banks; published 1978 by Input
Two-Nine Ltd; limp comvers,
119 pages; £9.95
If you want to buy a technical
book it’s for a purpose. You
want to obtain some informa- |
tion. The more specialised the |
information you want, the
harder it will be to find a book
to meet your requirements.
Conversely, if you choose a
book at random from a shelf it
the contents what kind of
learning need it would fulfill.
This is not a happy book.
No matter which way you look
at it, it’s hard to imagine any
need it could satisfy, other
than the financial one. It is
certainly expensive. Of its
nominal 119 pages excluding
introduction, quotes from pre-
vious reviews and a poor index
— there are at most the equiva-
lent of 90 pages of print. As |
they are in typewriting style,
the large-format pages carry
only the equivalent of a paper-
back of 100 pages.
The book is divided into
sections dealing with State-of-
the-Art, The Personal Compv- |
ter in Business, Software and
the Personal Computer and
The Industry View. In all
there are 13 articles, of which
at least five are written by
personnel of various com-
panies.
Supplement A is an article
from Practical Computing of
December, 1978, reprinted
without even the benefit of
editing to remove such redun-
dancies as the fact that the Pet
“was reviewed in our October
issue” and “In forthcoming
issues Of Practical Computing
we shall examine the three
approaches to buying a busi-
ness system”.
Supplement B is another |
reprint, a glossary of mic-
rocomputer terms from the
material Digital Equipment
issues with the LSI-11.
Conclusion
@ Definitely not recom-
mended. An expensive way to
obtain a small amount of infor- |
mation. The contents are defi-
nitely lightweight. If you know
the difference between a Pet
and a poodle you won’t learn
anything.-R.G.
93
94
Because we've got the
biggest and widest
range of micro-
computers,
there’s more for
you to bite on at
a Byte shop.
So you're
not only sure of
finding exactly
what you want: you
can take the opportunity to
experiment before you buy.
investment group, we'll be
here tomorrow as we are
today. All over the UK.
So whether you
business, for industry,
A for education — or
if you'd just like to find
out which model you
ger ont best with — you'll find a
Fe
And because we're a (ai) |
backed by the huge financial / paczae. | \
resources of a major a 2 |
Branches at: NOTTINGHAM: 92a Upper
LONDON (WEST END): Parliament Street —
48 Tottenham Court Rood — tel (0602) 40576
tel (01) 636 0647
want a micro-computer ee
for yourhome, your 4
visit to a Byte Shop a
new and invaluable
experience.
_ Ca \ You can
\ call at a Byte
Shop any time
from Monday to
Saturday.
the
RUIE SHOP bid
The Byte Shop
426/ Cranbrook Road,
Gants Hill, liford, Essex
Telephone: (01) 554 2177
Telex 897344
MANCHESTER: 7-8 Com
Exchange Building, Fennel
Street — tel (061) 834 0220
@ Circle No. 182
PRACTICAL COMPUTING July 1979
ees ees |) POPU
Printer tip
WE HEARD this one from reader Benny
Thomson of Norwood. It looks good for
business users and others writing fre-
quently to a printer. It seems you can
PEEK at (decimal) location 14312 to find
the line printer status. If it contains value
63, it is on and ready to print; 233 means
‘on but unavailable’; and 255 signifies
‘off’.
The point is that programs which do a
great deal of printer output can grind toa
halt if the printer is not available. So
Thomson offers this subroutine to be
called before an LPRINT:
9000 C = PEEK (14312
9010 IF C = 63 RETURN
and the rest of the subroutine takes you
away to do something else before trying
again.
Business user’s view
THE AUTHOR works for a large com-
mercial group which makes extensive use
of time-sharing bureaux but which is now
interested in the idea of cheap microcom-
puters for its staff. Company policy dic-
tates that the writer remains anonymous.
ALONG with many others, at the Tandy
presentations in London, we saw only the
Level 1 TRS-80; we were impressed and
subsequently we bought a 16K 2 Level 2
machine at a local Tandy store.
It has been in constant use since then
and its performance has been sufficiently |
impressive for it now to have a major
impact on our entire approach to the use
of computer-based techniques.
That is not to say there have not been
problems. First, Level 2 is essential for
sensible computing, though you need a
good grasp of Basic before you can use
the manual - in contrast to the superb
Level 1 introduction.
Twice as fast
With the Level 2 system, the cassette
tape is read and written twice as fast as
Level 1; this must be close to the
reasonable limits of a domestic cassette
recorder, as our system has been very
prone to load errors, in spite of the fact
that we use digital-quality tapes and have
had our cassette recorder modified to
reduce hum and to improve the control of
the mechanism. In our view, both are
absolutely essential modifications,
though load errors have still not been
eliminated.
It is critical to check volume levels and
stay at the one which is acceptable. We
clean the tape-heads each day and have a
tape-head de-magnetiser. As a matter of
procedure we save four copies of long
programs and we always use CLOAD? to
check the integrity of each copy.
There has also been a distinct lack of
software until recently, a situation which
is now improving. We have bought a re-
numbering system and are about to
obtain the Electric Pencil word processor
— it is difficult to appreciate the full power
of this software because it is all priced
very economically.
PRACTICAL COMPUTING July 1979
Our only other major complaint is that
without the disc system we are limited to
one system routine at a time and there
can be a noticeable impact on memory.
Still, one can at least assess the pros and
} cons — which is of course the Tandy
intention — and then make the disc
upgrade.
Startling
We were fortunate that we already had
a Texas Instruments Silent 700 ASR, a
30cps thermal printer terminals. For £50
we could buy a TRS 232 interface to link
it to the TRS-80. As the associated
software diverts the print output to the
cassette recorder leads, we obtain hard-
copy on this terminal without the Tandy
expansion interface. Even more startling
to us is the claim that the associated
software can drive a printer at 9,600 baud
- so much for the 1,200 baud limitation
that the bureau was using.
Two interesting considerations
emerged from the interface exercise. We
had already discovered that there was a
high degree of overlap between the TRS-
80 Basic and that of the time-sharing
bureau. This overlap provided the
mechanism for using the TRS-80 for
program development. The cassettes on
the Silent 7000 ASR provided the means
of capturing this program and transmit-
ting the tested program to the bureau.
TANDY FORUM is devoted to the Tandy TRS-80. We will be using it _
to pass on news about the TRS-80 and its supplier and product —
announcements from Tandy and other vendors of compatible
equipment. Above all, these are pages for users, and would-be
users, of this personal computer. We want you to send tips,
queries, moans and comments, and we want this page to become
a market-place for TRS-80 Information.
| impressively low cost. If we can obtain a
| to load both data and programs into the
We consider that the TRS-80 can also
work as a fairly sophisticated data-
capture device working in a similar
manner. Given that intelligent terminals
cost £10,000 or more, the TRS-80 can
provide many of these features — arguably
with more processing power — at an
two-way RS232 interface we will be able
TRS-80; that will duplicate ali the fea-
tures of an intelligent terminal com-
| pletely.
| Characters lost
The second point is that we were able
to alter the associated software for the
RS232 interface. With program lines
greater than the 80-character print width
of the Silent 700, characters were lost
while the carriage return was operating.
This also occurs with the time-sharing
bureau and is due to a lack of delay
characters (nulls) with a terminal-
generated as opposed to a system-
generated end of line.
The print software now counts the
length of each line and when the specified
print width is exceeded will supply the
necessary nulls. It also proved possible to
provide some extra code, so that we
could also obtain a screen print from the
contents of the disc memory — though not
for the graphics, unfortunately.
This is done by making the extra code a
USR with a CALL to the print driver
routine for each character to be printed.
As it iS written in machine code, this
routine should also operate at up to 9,600
baud.
Outlay saved
We see the TRS-80 as a very versatile
piece of equipment. It can be considered
a word processor, intelligent terminal, or
key-to-tape for processor. We feel our
initial outlay has already been saved
several times in terms of a reduction in
external expenditure with time-sharing
bureaux. It has also opened the door to
many applications which could not be
justified in a £20 to £30 per hour cost
environment.
Given that micros compete with many
of the peripheral activities of a main-
frame installation and often with much
better response times, the next few years
will show exactly how far the design
concept can go.
The only real constraint, it seems to us,
is data storage — for both reliability and
volume. When this becomes available at
a cost comparable to that of the CPU,
one really will be close to having an IBM
370 on one’s desk top.
95
SMALL BUSINESS SYSTEM WITH
NORTH STAR
HORIZON
Horizon microcomputer with dual. double density
disk drives, 2 serial ports, 2 parallel ports 24K ram
£1,913
Extra 8K ram boards £155 each
VISUAL DISPLAY UNITS
Hazeltine
1400 £550
1410 £595
1500 £785
PRINTERS
Deewriter II £900 Anadex DP 8000 £575
Teletype 43K P £900 Single part paper for
Teletype 43 (friction) £920 | Anadex £8 per 1000 sheets
APPLICATION SOFTWARE
Sales ledger, Purchase ledger, Stock recording,
Letter writer, Word Processing, Payroll, Estate
Agent’s system etc.
Lear Siegler
ADM 3A £630
ADM 31 £830
We can provide consultancy service
for any application software
MICRODATA
58 High Street, Prescot, Merseyside
Tel: 051-426 7271
gx. HAPPY
TP MEMORIES
21L02 450ns 80p Pia "A5Ons 25°25
21L02 250ns 95p 2114 300ns £6:00
4116 250ns £7.50 2708 450ns £6°75
TRS-80 16K Memory Upgrade Kit £75
Full instructions included
$100 16K Static RAM Kit 450ns £195
Bank select, 4K boundaries, all sockets,
components and instructions included
with 4K £81: with 8K £119: with 12K £157
ASCII Keyboards from the USA £48°50
59 keys, 128 characters, alpha-lock, repeat,
pos and neg strobe, send SAE for data sheet
Science of Cambridge Mk 14 set of 18
Texas low-profile sockets £2-80
Texas low-profile DIL sockets:
pins 8 14 16 18, 20922574"238' 40
pence 10 11 12 17 18 20 22 28 38
Antex Imm bits CCN or CX17 45p
Call or write for 74LS price list
VAT included, 20p p +p under £10 order
5 Cranbury Terrace, Southampton
Hants S$O20LH_ Tel. (0703) 39267
@ Circle No. 185
@ Circle No. 184
Cource
Micro Computer Consultants
12 Vivian Road,
Wellingborough,
Northamptonshire,
Telephone: (0933) 224040
Source introduces: BUSINESS SYSTEMS
Accounts General, sales, purchase ledger, VAT, comprehensive report
structure etc.
Mail Selective data retrieval (names and addresses) for input to
a word processor to produce mailshots, reminder letters etc.
Parts Stock control system with re-order limits, audit trail,
comprehensive reports etc.
One or all of these 3 modules may be combined to produce an interlinking package.
The above fs available on our two systems :
System 1 0.6 MB, single user from £4,955
System 2. 10MB, multiuser from £11,600
2 day installation plan £200.
The quoted prices are for hardware only and exclude VAT.
Software prices are not quoted as the packages will need tailoring to
suit individual businesses.
@ Circle No. 186
96 PRACTICAL COMPUTING July 1979
a ee ae |
User group news
SINCE April, when the user group came
into being and was first publicised,
response has been good, but it could be
better. Membership is growing daily and
every post brings more enquiries: the
problem is, however, that most of them
are from the hobbyist.
There is nothing wrong with that but
many Apples have been sold into busi-
ness; so businessmen, please note, you
need the Apple Users’ groups, too.
User groups form an important back-
up service; the more members they have
the more information available to all.
Surprisingly, one group from which re-
sponse has been small is the Apple
dealers. So far we have had only one
reply from the 14 distributors.
Making life easy
Applesoft I] is an easy language to use
but in it there are a few traps for the
unwary. For instance, this statement will
cause problems:
IF Y = A THEN PRINT I
Apple won’t print I; in fact, you’ll get
SYNTAX ERROR.
This is because the Applesoft parsing
action causes the statement to be read as:
IF Y = AT THEN PRINT I
Hence the syntax error.
The solution is simple; enclose ‘A’ in
parenthesis. This will stop Applesoft
parsing of the letter combination and thus
‘recognising’ the reserved word AT. So if
this statement is entered everything will
be fine:
IF Y = (A) THEN PRINT I
All roads lead to ROM
PROGRAMS written using the Applesoft
ROM card will not run if Applesoft is
loaded from tape or disc; programs
written without a ROM card, using the
tape or disc Applesoft, won’t run either,
but don’t despair. To run a program
written using the ROM card, LOAD the
program and then CALL 3314. It should
then run.
A program written using the disc or
tape Applesoft can be run with the ROM
card by LOADing the program and
typing CALL 54514.
These CALL statements move the
memory pointers to the appropriate
place; the tape or disc Applesoft will
occupy a different location in the memory
from the ROM version and consequently
the program will start at a different
position.
Manual problem
THOSE users who have bought disc drives
will probably be disappointed with the
rather brief documentation. Apple has
promised a new manual, but until it
appears we’ll try and smooth out some of
the hassles.
PRACTICAL COMPUTING July 1979
One problem with the disc is under-
standing its information format. Data can
be written as fixed-length records or
random-length records. All data is writ-
ten in ASCII.
Fixed-length records are written when
you OPEN the file with an ‘L’ parameter.
So OPEN DAN, L 40 will create a file
named DAN whose records are all 40
bytes long. If you put only 20 bytes of |
information into each record, you will
waste 20 bytes per record of space.
Random-length records are one byte
each but are grouped into blocks which
are up to 32K bytes long. Each block or
logical record ends with a carriage return.
Note that this means that the number ‘1’
requires two bytes — the number followed
by a RETURN - and the number ‘10’ will
require three bytes. If you forget this and
later replace ‘1’ with ‘10’ you will destroy
part of the following record, which is not
exactly good programming practice.
Graphics programs
LENGTHY programs involving a fair
amount of string handling and graphics
may be limited because the string space
fills with old data and runs over into the
high-resolution screens.
To initiate some house cleaning and
avoid this problem, two things can be
done:
@ Insert X = FRE (@) into your
program, which deletes all unused
strings.
@ Set the address of the lowest memory
location the program can use above
the H resolution graphics screens.
LOMEN: 24576 will enable you to use
both pages 1 and 2 of the high-
resolution graphics.
Graphics re-visited
LOOKING through an issue of Contract,
the American Apple User Group news-
letter, we found a neat summary of how
to use both pages 1 and 2 of the memory.
Ordinarily, Apple displays only page 1
of its memory locations — locations 1024-
2047 — but it is possible to display page 2 -
locations 2048-3071 — as well; if you know
how to do this, use of page 2 will give you
‘instant’ black screens and snap your
graphics or text material on and off
clearly.
Before you can use page 2, however,
you must tell Apple not to put any
variables in locations lower than 3072 — in
other words, set LOMEN: 3072. After
| you have done this, you are free to move
| the contents of page 1 to page 2, re-load
page 1 with new data and switch back and
forth between the two pages.
Here is how to do it, using the general-
purpose block movement routines built
| into the Apple monitor:
POKE 60 (old starting address mod 256)
POKE 61 (old starting address /256)
POKE 62 (old ending address mod 256)
POKE 63 (old ending address /256)
POKE 66 (new starting address mod 256)
POKE 67 {new starting address /256)
CALL-468 (the actual move command)
Now, to use page 2 sabi gig to set LOEME: 3072 be higher):
55:
10 KE 60, 0: POKE 61, 4: POKE 62, 2
POKE 63, 7: POKE 66, 0: POKE 67, 8: CALL- 468:
POKE - 16229.0
To switch back and forth between pages 1 and 2:
POKE ~ 16299.0 (display page 2)
POKE - 16300,0 (display page 1)
If both pages contain similar graphics
figures, switching between them will yield
simple animation. Further effects may be
gleaned from an inspection of the list of
POKES on page 30 of the Apple II
Reference Manual.
Note that this will not work with
Applesoft in ROMs. It starts at hex 800,
the second page of graphic space. A
block move into this area will lose your
Applesoft Basic.
Apple Shoppe
APPLE Shoppe is the name of an interest-
ing newsletter we received from a |
Californian computer shop, Computer
Components of Orange County. Volume
1 Number 1 was produced on the Apple
II with a $50 word processor package and
a Trandcom thermal printer — somewhat
ugly workaday output with no true
descenders.
Most of its 16 pages are interesting and/
or useful. We have asked permission to
reprint two pieces, including a neat
introduction to the Apple disc and a
clever workshop, article on How to write
a mailing list program.
PAM
| PAM is a Pet add-on memory from OMB |
Electronics. It is available in 8K, 16K,
| 24K and 32K versions. The 24K version
| upgrades the Pet memory to the full 32K
addressable in Basic; 8K cards are
available separately to augment 8K, 16K
and 24K versions at a later date.
Operation if by plugging-in to the
memory expansion port, using the con-
nector provided, and to the mains. Pet
power consumption, temperature and,
most important, the Commodore warran-
ty are unaffected.
The cash-with-order price of the 24K
unit is £310 plus £4-75 carriage and
insurance, excluding VAT. Delivery is
normally ex-stock but telephone 0322
863567 for confirmation. a
97
Trainyour PET
inaccountingsystems
OPETAL
Ls ese is ACT's way of putting Analysis and
Ledgers on your 8K Commodore PET.
Wares Ledger
with complete Statement/Remittance Advice, Debtors Control
List and Overdue Letters.
PB Purchase Ledger
with complete P.L. Record/Remittance Advice, Creditors
Control List and Credit Transfers
B Analysis
a powerful analysis system allowing full management reporting.
— VAT Analysis
a purpose built dnalysis to take away the VAT blues.
Z
OPRETA L... combines all the advantages of your own
Commodore PET together with a low cost Bureau Service.
98
Applied Computer Techrtiques Limited
Graphic House
Telephone Avenue
Bristol BS1 4BS.
Telephone 0272 211733
PC1
@ Circle No. 186
PRACTICAL COMPUTING July 1979
How to interface to a
mainframe computer
COMPUTERS can talk to each other. In
particular, microcomputers can talk to
mini’ or large mainframes and there are
good reasons to do so, as a great deal
more than aesthetic pleasure can be
derived from their union. Distributed
processing of this form can be used to
implement data entry systems, point-of-
sale data capture, and many other cost-
effective organisations. At the very least
the micro can save the mainframe user
the price of a VDU.
These articles will deal with the Com-
modore Pet because of its popularity,
though the unusual design of the key-
board on the 8K Pet and its interfaces
make it an unlikely prospect for intelli-
gent terminal work.
First let us deal with interfacing the Pet
to a mainframe computer. Do you have a
hard-wired line, or will you be using a
modem? A direct connection via a hard-
wired line is the easiest to work with but
it requires close proximity.
Given that you are more likely to use a
modem, you can chose one of two ways.
You can stay with the IEEE interface on
the Pet and buy an JEEE-standard
modem - a somewhat esoteric device in
today’s context; or you can opt for an
RS232 modem plus an RS232 interface
adaptor.
Two options
I prefer the latter course. An RS232
modem is much easier to obtain second-
hand and bi-directional IEEE 488/RS232
THIS is the first of two articles which discuss how microcomputers —
specifically the 8K Commodore Pet — can be used to communicate
with other computers in distributed networks. The author is
technical director of Computastore Ltd, a Manchester-based com-
interface adaptors are available widely — I
use the one from Bailey Associates.
The cost of the two options is about the
same but having an RS232 interface on
the Pet also provides the great advantage
of being able to use any RS232 printer on
the market.
by Michael Whitehead
If you decide to implement the project
outlined in these articles, you can obtain
an RS232 modem in the form of an
acoustic coupler - which is just an
ordinary telephone handset ~ from any
manufacturer of computer peripherals.
Anderson-Jacobson has a good reputa-
tion, though a new AJ coupler will cost
more than £200. ,
You probably will not be able to beat
Modular Technology for price for a new
one. You might also be able to get one
from a second-hand dealer like Elec-
tronic Brokers Ltd or possibly you could
contact an amateur computer club which
has one.
Remote-access bureaux use them a
great deal, so if you have contacts in one
of them try that source.
For the interface adaptor, though, you
do not have much alternative but to order
PRACTICAL COMPUTING July 1979:
pany primarily concerned with business systems.
new; try Bailey Associates, Amplicon or
SDK Projects.
The second requirement is the dial-up
number of the destination, plus informa-
tion on the communications protocol,
transmission rates and parity, passwords
if relevant, operating system, editor, and
high-level languages available. If you are
uSing a mainframe, most of this informa-
tion should be relatively easy to obtain,
except perhaps for details on the pro-
tocol.
The most common transmission rate is
300 baud (bits per second) which equates
roughly to 30 characters per second; each
character consists of eight data bits, plus
a start bit and a stop bit. You cannot use
an acoustic coupler at data rates above
this, incidentally.
A rate of 110 baud is also common; it
represents the transmission of 10 charac-
ters per second, as each character is
followed by two stop bits at this slower
rate.
The Bailey interface contains a number
of switches which allow your Pet to talk
to other RS232 devices at any of a wide
range of speeds, although it may take a
little trial and error to decide on the
correct parity and stop-bit settings.
Then the only thing you need is some
software to allow your Pet to drive its
built-in IEEE interface quickly and effi-
ciently. Although the Bailey adaptor
permits the Pet to communicate at the
RS232 standard, all data entering or
leaving the Pet must go through the
IEEE interface, so this must be the target
for your software.
Novelty
To start, you want to be able to input
and output characters. It can be done
from Pet Basic, a novelty with which you
may want to experiment for an hour or
so. Once the excitement wanes, however,’
it becomes very clear that Pet Basic is not
even fast enough to simulate a dumb
terminal running at 110 baud. Surely we
are aiming for a much higher form of life.
With Basic out of the running, that
leaves Assembler. But where, you might
ask, are all the ROM routines which Pet
Basic uses to drive the IEEE interface?
How can I assess them from Assembler?
(continued on page 101)
99
Pet COrncr aaa
EXIDY INC.
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Ohio SUPERBOARD II 8K Basic Built & Tested £284.95
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STARCHESS Colour TV Game (Space Age Chess) £6495. £59.50
ELECTRONIC MASTERMIND Pocket-size 3, 4 or 5 Digits £14.90
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SAE with all enquiries — All price inclusive VAT
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| Fi fT
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Circle No. 189
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@ Circle No. 188 @ Circle No. 190
|9O PRACTICAL COMPUTING July 1979
We have most of the latest range of' Commo-
dore equipment, business software, games
etc. We also have other machines in stock and
instruction in use of systems is available.
another branch
opening soon in
Westminster
LOGIC BOX
Planer Building
Windmill Road,
Sunbury, Middx.
(09327) 86262 Telex 928185
(continued from page 99)
Let us deal first with output, as it’s
easier. The general steps required are to
assign an IEEE listener device, output
one or more characters to that device,
and then to de-assign that listener. The
routine in figure 1 may be called from an
assembler program to output a character
in the accumulator.
This routine is only 39 bytes long and if
used intelligently will run at speeds of up
to 9,600 baud. You may also want to add
some code to it to convert lower-case
characters from their Pet representation
to ASCII, though it is suggested that the
Bailey interface will soon do it for you.
Note that the aforementioned code
assumes a listener-device-address of four,
which is that of the Bailey interface; later
my input routine will assume a talker-
PRACTICAL COMPUTING July 1979
device-address of six, for the same
reason. Also note that some Pet As-
semblers will not assemble this code, as it
involves symbols with a value higher than
32K. If this is a problem for you, use the
Computastore assembler — it does not
have this restriction.
When we feel confident of being able
to output at least one character to
another computer, how about input?
Sadly the answer is not perfectly satisfac-
tory. The general scenario for inputting a
character from the IEEE interface is:
@ Assign an IEEE talker device.
@ Listen until it either comes up with a
character or times-out.
@ De-assign all talker devices.
@ if you still have no character, go back to
the first step. This scenario is im-
plemented by the routine in figure 2,
which always returns with a valid
character in the accumulator.
Unfortunately, there is a problem
which centres on a PIA register at
location SE84D used to control the 64-
millisecond time-out on input. Unless it
can be re-set to zero, any call to the ROM
IEEE input routine will be doomed to fail
immediately on a time-out.
Not solved
Although I have spoken to Commo-
dore about the problem, it has not’ yet
been solved. For the moment the solution’
is to copy the ROM routine but to use
some other mechanism to effect a time-
out, such as looping around the input-
status-test instruction a maximum
number of times.
That is the approach which has been
taken in the input program presented in
figure 2. It works well but unfortunately
it slows the whole process somewhat, so
that it will not run reliably at speeds
greater than 600 baud.
As with the output routine, you may
wish to modify the input routine in figure
2 to convert incoming lower-case charac-
ters to their equivalent Pet representa-
tion.
So we can input and output characters.
How do we assemble our building
blocks? A feasible project might be a
dumb terminal simulator, often called a
termulator routine. That kind of prog-
ram, while executing, might convert your
Pet into, for example, a 300 baud full-
duplex upper-case-only VDU.
Next month I shall offer such a
program and discuss some of the more
interesting aspects of distributed comput-
ing of which Pet owners are capable.
Addresses
Computastore Ltd
16 John Dalton Street
Manchester 2
061-224 9545
R. Bailey Associates Ltd
62 New Cavendish Street
London W1M 7LD
01-637 .0777
Anderson Jacobson Ltd
The Estate Office
Station Approach
Shepperton, Middlesex TW17 8AP
09322 44439
Electronic Brokers Ltd
49-53 Pancras Road
London NW1 20B
01-837 7781
Modular Technology
PO Box 117
Watford, Herts WD1 4PD
01-421 0626
SDK Projects
39 Eveline Road
Mitcham, Surrey
01-640 5492 lia
101
Payroll, Pete and Friends
Professional PET Software
At law
To help you get the most out of your Commodore PET,
Computastore has developed a range of software
gress packages to cope with the demands of both
Industry and Education.
“ PAYROLL: Runs on the 8K PET and produces pre-
printed payslips, totals and coin analysis.
PETE: Turns your PET into an intelligent RS-232
terminal for use with a mainframe.
PETROFF: A text formatter to produce neatly typed reports.
ALSO: Assembler, Disassembler, Renumber, Keyboard.
Contact your PET dealer or
Computastore for a demonstration.
~/ Computastore
Software that means business
Computastore Ltd, 16 John Dalton Street,
Manchester M2 6HG. Tel: 061 224 9545
@ Circle No. 191
TRS 80 PAYTALK
THE PAYROLL PROGRAM WHICH SETS THE STANDARD
PAYTALK makes an immediate contribution to your business. It lets anyone handle PAYE complexities. Just type
simple payroll facts and PAYTALK instantly responds with full P11 deduction card results and payslip details. Deal
with any number of employees and then screen payroll totals to enter up your accounts. It needs no printer — just
16K of RAM and one cassette drive.
COMPREHENSIVE All tax code types. Any pay interval. N.I. includes contracted-out. Week 53 handled.
Pension deductions. etc. etc.
PROFESSIONAL Performs on the computer method specified by the Inland Revenue. Developed by a
Software House with over 10 years’ experience.
CONVERSATIONAL A simple question-and-answer operation methodically checks your replies. The
program runs with superb clarity.
SUPPORTED Full instruction manual — itself a mode! of clarity. New program cassettes are
produced for PAYE changes.
£50 for the program cassette and instruction manual
TAY COMMERCIAL SERVICES LTO sole UK supplier
PO Box 36, Bury, Greater Manchester (061) 7645744
@ Circle No. 192
102 PRACTICAL COMPUTING July 1979
ee)
Finding the good days
Everyone has ups and downs. Biorhythm theory suggests that those ups and downs
aren’t as arbitary as they seem. There is some evidence to suggest that good and bad
days follow regular cycles throughout your life from the moment of birth. It’s
possible to calculate those cycles — and here is a program to do it.
CELL EEK EEK EEE KEKE ELE KE#DD DDDDDDIPIIIIZIZIIDIZIIIIDIDIDIDDDDDD?-_| | THERE are three biorhythm cycles, and
PASSIVE CRITICAL ACTIVE while each may vary in intensity of effect, |
KEKE ELE EEE EEE EEE EEK EEE EEK E EK KK KEES DDD DPD DPIDIDDIIPDIIIPPDIDPPPDIDIPIIIDD they do not vary in length. The shortest is
the 23-day physical cycle, affecting
energy and self-confidence. The sensitivi- |
ty, or emotional cycle, is 28 days, and
governs mood, optimis, irritability. The
intellectual cycle, 33 days, controls the
ability to be logical, to absorb and recall |
facts, and powers of reasoning.
Each cycle goes through a positive -
plus or active ~ phase and a negative or
regenerative — minus or passive — phase.
On the physical cycle, the 112 days are
held to be a good time for intensive
training in athletics or for any activity
requiring physical stamina. Those plus
days represent physical strength, endur-
ance, energy, resistance to infection and
disease, and physical confidence. Some
doctors, we gather, will perform
scheduled surgery only between the
| second and ninth day of this cycle.
On the minus days of your physical
cycle you are re-charging and you tend to
tire more easily. That is a good time for
athletes to train to store energy.
by Martin Collins
APR 1979
f
The 28-day emotional cycle corres-
ponds approximately to a woman’s men-
| trual cycle; it is not identical to it, though,
and it occurs in both men and women, On
the plus days you are likely to be
cheerful, co-operative, considerate, crea-
tive and loving; generally you should
have a positive outlook on life.
Conversely, the 14 minus days are
conducive to moodiness and negativism.
You may exhibit signs of irritability.
Awareness of that fact is important to
drivers, operators of complex machinery
and others who need to react quickly and
rely on sound judgment.
The first half of your 33-day intellectu-
al cycle is the best time to absorb new
subjects. A person finds it easier to study, |
write creatively, understand mathematics |
or pursue any intellectual efforts. Equal- |
ly, your intellectual faculties will be less
keen during the last half of this cycle.
The highs and lows vary with individu-
als. Factors such as age, excitability and
health determine to what degree these
traits ‘will apply to each person. The day
your cycle changes from a plus to a
CHART PREPARED FOR BOB BIRTHDATE 21 7 1958 _ minus or from a minus to a plus is critical;
| (continued on page 105) |
KEKE EEK EEE EEK EE EEE EEE EK KEELE DD DDD IDDDIII>III DIDI DD DDD D> DDD DDD DIID
PRACTICAL COMPUTING July 1979 103
existing system. ware.
For Service @ Software @ Sales call
on: St. Austell 0726-61000. Blagdon 0761-62435.
NORTH STAR HORIZON
Benchmark Computer Systems Ltd. agent for Bristol & S.West
Service Software Sales
On-site or depot (Bristol) maintenance North Star Dos, Monitor BASIC and Horizon—-I— 16K : £1,265
contracts for North Star Horizon and PASCAL. CP/M with CBASIC, Fortran —I— 32K: «£1,445
peripherals. Field enhancements to your and Cobol. Business Systems and soft- —2— 16K : £1,575
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Decwriter LA36 : «£925
VDU : £700
all prices exclude VAT and carriage.
Benchmark Computer Systems Ltd, Tremena Manor, Tremena Road, St. Austell, Cornwall PL25 5QG.
@ Circle No. 193
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Also send for details for our Microprocessor
SEMEL 1
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ie
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Tel: 0822 5439 Telex: 45263
@ Circle No. 194
FQUINOX 300
A powerful multi-user
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a digitizer adds another dimension:
The Bit Pad computer digitizer converts graphic
information into digital form for direct entry intoa computer.
computer. By touching a pen like stylus or a
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cabinet.
information and details.
Terminal Display Systems Ltd., Hillside, Whitebirk Industrial Estate, Blackburn 881 5SM, Lancs, England
Send to: Department CPPC, Terminal Display Systems Ltd., Hillside, Whitebirk Industrial Estate.
Blackburn BBI 5SM, Lancs, England.
ets eee eee eee ee |
| Address ....
@ Bit Pad interfaces with almost any micro
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Fill in the coupon and we will send you full
ork Architecture
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PRACTICAL COMPUTING July 1979
Se a ae
(continued from page 103)
you are neither up nor down but in a state
of limbo.
Tied to the biorhythm theory is the
theory of body harmonics — that ups and
downs are stresses which spend them-
selves in curving, pendulum-like waves.
The critical period does not necessarily
mean you will make mistakes or have
accidents; it means you are more likely to
make errors of judgment and be general-
ly less acceptive. Once you know when to
expect mistakes, you can also use that
information to your advantage, most
obviously by timing important decisions
and actions to avoid your critical days.
If one day per cycle is critical, things
can be difficult. With criticals coinciding
on two or three cycles, your vulnerability
and your problems are magnified. Simi-
larly, if two or three cycles peak at the
same time, you ought to be at your most
effective.
Perhaps it may be regarded as trivial
1 OPEN 4,4,1
3 PRINT"3"
5 REM BIORHYTHMS
6 DIM .N$ (20) ,D(12),LS (61) ,-P(23)
nonsense, but the body of scientific and
statistical opinion suggests otherwise.
Doctors and sportsmen seem the two
groups who are keenest on biorhythm
theory. Around the world there are
research centres of varying degrees of
authenticity, including the Biorhythm
Research Association at Normanton-on-
Soar, Loughborough, Leicestershire.
BRA has an impressive suite of
documentation on the subject if you want
to pursue it.
The program was written originally for
. a minicomputer and converted for a Pet.
We have tried to keep the Basic as non-
specific as possible, so most of the
statement lines should transfer easily to
other microcomputers.
The exceptions are line 3, which clears
the screen, and several lines which
reference a printer channel, including
line 1, which opens the channel.
We ran the printout on a Diablo
daisywheel printer without English:
3u5U LF E(E1)<>P(P1) HEN 670
dou LS(E(E1))="+"
870 LE P(P1)<>1(11) ‘HEN 69U
ooU LS (k(P1))="+"
o¥U PRINTEG,” ";
characters, so the hash sign # is printed
as a pound sign. All our PRINT state-
ments (line 90 onwards) send data to the |
print channel; in the Pet Basic it is done
with the statement PRINT +4 (print on
channel 4) but our listing reproduced this
as PRINT£4, for which we apologise.
For the sample run we omitted lines
1024 and 1026. They give a row of dots on
the right of the printout for each date; is
a kind of diary facility for you to add
notes but obviously it requires you to
have a printer capable of printing more
than 80 columns across the page.
The program asks for your birth-date,
then calculates and prints your
biorhythms. Obviously, ‘I’ denotes the
intellectual cycle, ‘P’ the physical ‘E’ the
emotional.
When two cycles coincide, the letters |
are replaced by a plus sign. The dotted
line down the centre shows the crossover |
point; critical dates are flagged by aster-
isks in the left.
7 DIM £(28) ,1(33) ,M$(36) ,HS (40) Ul LEE (E1)=331 THEN FRINLES "8"; 222%
B FORL=1T020:NS=NS+" ":NEXTI 902 IFP(P1)=31 nen PRInTe4,"*
9 FORI=1T061:LS=LS$+" " :NEXTI $US TEE (11)=31 THEN Prinred,"*"
10 FOR 1=]1TO36:MS=M$+" ":NEXTI Q1U PRLNIE4 SPC (4-2) :2=0
1a eo elie 94U Le JC1U ‘tHEN PRINIES,” ";
15 MS="JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC" 1U0U PRINTES, J;
60 FOR I=] 10 23:READ P(1):NEXT Juul FUR I=] 10 61: FRINTES,LS (1) ;:NEXT 1
70 FOR I=] TO 28:READ E(1):NEXT 10UZ PUR K=1 TU 39
80 FOR I=] TO 33:READ 1(1):NEXT lous H$(K)=" "
90 FOR I=] TO 12:READ D({1) :NEXT 1004 NEAT K
FORI=1T010: PRINT: NEXTI : INPUT" ENTER YOUR NAME" ;NS 1WUu5 HS (4u)=":"
PRINT" ENTER YOUR DATE OF BIRTH" 1007 IF P(P1)<>35 ‘nin luls
QUSUB 1100 1uU9 HS$(z)="*"
INPUT"ENTER DAIE FOR CHARI (MONTH, YEAR)" ;S2,S3 1011 Hy (4U)="P"
IF SZ>120RS2<1 THEN 240 1ul5 1f 1(11)<>34 Then 1024
IF S3<100 THEN $3=S3+1900 lule Ifn$(z)<>"*"IHENHS (2) ="*" :GOLUluly
IF S3<190U THEN 240 1ul7 #$(3)="*"
IF $3+S2/12<B3+B2/12 THEN 24U uly HS(40)="2"
Sl=1 luzu IF 1(11)#3@ AND P(P1)=35 THEN H$ (40) ="+"
A=0 luz4 PRINTE4 ,oPC(17);".
IF B3+1>S3~1THEN340 1025 POR I=] 1U@u:FRINTE4S, HS (1) 3 NCAT 1
PUR Y= (B3+1)10(S3-1) 1UZO PRINLES SEC (47) "occ cee cece cece eeee Bi oreidgia. rpm's ai Hao Poa strsieare ‘ns
1F INT(¥/4)*4<>Y ‘IHEN 330 luz? NEXL J
A=A+1 1020 GuSub 14uU
NEXT Y lu3u Gulu ZuU
Dl=(S3-B3-1)*365+A llvu Kem
IF INT (Y¥/4)*4<>Y ‘IHEN 360 llul INPUL"
1F B2<¢>2 ‘THEN 380 1lu5 Ineur" MONTH" 7 BZ
p1=D1+1 lllu INpur" YEAR" ; 53
D1=C1+D (62) -Bb1+1 1119 1F BZ>1z2 ‘WHEW lig
1P82=1Z1HEN4ZO llzv IF 61529 AND b2Z=2 ‘THEN 1137
FOR I= (B2+1)u lz 1137 IF 83<1UU THkN Bs=b5+190U
01=D1+D (1) 1136 IF 6321979 “InHEN lluU
NEXT I 1199 RETURN
IF $2=1 THEN Suu 1200 GuSUB ZUUU
FOR I=] 0 Sz-1 1Zlu PRINTE4 : PRENT'ES
D1=b1+0(1) 1230 GuSuB 2000
NEXT { 1275 GuSUB 130uU
Pl=01-IN1(D1/23) *23 1280 PRINIE4,"
£1=DI-INI (D1/26) *28 1285 GusUB 1300
11=D1-1n1 (01/33) *33 1286 PRINTE4
B(2)=26 1287 PRINTE4 ,MIDS (MS, (M-1) *541,3);
M=S2Z 1268 PRINLE4 ,S3;1AB (78) ; "NOLES"
Gusus 1200 1290 PRINTES
FOR g=1 10 O(M) 1295 REAURN
FOR K=1 10 61 UROU PRINTED "6666 666 CCE EEE CCF
LS(K)="_° 1310 PRINTE4 ,“>>>>>>>>>>>>>>>>>>>>>>>>>>>9>>>>>9999"%
NEXT « 1320 RETURN
LS$(31)=":" l4uu PRINTE£4
Pl=Pl+1 1410 Gusus 1300
LP B1¢24 ‘nen 7 1420 PRINTE4
Pl=1 ~ 1430 PRINTE4 ,”
L$ (e(P1))="P" 1440 GOsuB Z00U
E1=E1+1 1460 RETURN
1F £1<29 QHEN 7 1900 DATA 31,39,47,53,58,6U,61,59, 56,50,43,35,27,19,12,6,3,1,2,4,9,15, 22
El=1 1910 DATA 31,38, 44,50,54,58,60,61,60,58,54,50,44, 38,31, 24,14,12,6,4,2,1,2
LS (E(E1))="E" 1920 DAILA 4,8,12,18,24
11-1141 193U DATA 31,37,42,47,52,55,58,60,61,61,59,57,54,50, 45,39, 34,26, 23,17,12,8
LF 11¢34 ‘inkN 620 1940 DATA 5,3,1,1,2,4,7,10,15,20,25
il=] 1950 DATA 31, 28,31,30,31,30,31,31,50,31, 30,31
CSL (21) 261" 2000 FOR XX=1 TO 6: PRINTE4:NEXTXX
} 1F E(61)<>1(11) THEN &5u 2001 RETURN
LS (b(E1)) ="+" 9999 CLOSE 4:END
DAY" ;B1
PASSIVE CRITICAL ACTIVE”
CHART PREPARED FORK ";NS;" BIKIHUATE ";61;62;B3
PRACTICAL COMPUTING July 1979 105
HEAVY DUTY PRINTER
FOR
PET . SWTP HORIZON APPLE
SORCERER . CROMEMCO . ETC
ANADEX D.P 8000
80 COL. FAST 1120PS S&
BIDIRECTIONAL PRINTING.
VERY GOOD PRINT
QUALITY UPPER/LOWER CASE. £ SIGN.
COMPLETE siecrsunscanss*
READY TO GO £575+VAT
FOR PETS, ALL ABOVE + INTERFACE £195
Also available:
COMPLETE BUSINESS SYSTEMS
DIABLO HYTERM 1620
£2700
£2000
Write or Phone for further details or demonstration
LONDON COMPUTER STORE
43 GRAFTON WAY
Off Tottenham Crt. Rd., London W.1
01-388 5721 OPEN 11-7 Mon-Fri 11-4 Sats.
@ Circle No. 197
The U.K.-designed and manufactured Novapak disk system
for Commodore's PET*, first seen at Compec ‘78, is (after
extensive industrial evaluation), now available to the domestic
user. [ts unique saddle configuration continues the integrated
design concept of your PET, with no trailing wires or bulky
desk-top modules.
*%* Novapac may be used with any available RAM plane.
%* May be used with latest versions of PET.
* Data transfer takes place at 15,000 char/sec - effectively
1,000 times faster than cassette!
* Storage capacity is 125 K/bytes (unformatted) on 40 tracks
per diskette side.
* Dual index sensors permit dual-side recording for 250 K/
bytes per diskette.
* Easy operation full-width doors prevent media damage.
%* System expandable to } Mbyte on-line storage (4 drives).
* Dual head and 2D versions provide 2 Mbytes on-line.
* Industry Standard IBM 3740 recording format for industry-
wide media compatibility offered only by NOVAPAK.
* Dedicated Intel 8048 microprocessor and 1771 FDC minim-
ise PET software overhead.
* Local hardware and software support available.
106
BB) Gentlemen, the Petdisk
ayy fas landed... .
analog electronics
Introducing
LEVEL Ill BASIC
forthe TRS 80
From Hardings—always first with new TRS-80
software. A new 5K Basic interpreter from Microsoft
who wrote Level II. Fully interacts with your existing
Level II to give you the most powerful Basic available
for any microcomputer. Fantastic capability for your
machine with powerful editing command, new
graphic commands, easier cassette loading, elimin-
ation of keyboard bounce, full error messages, hex
and octal constants and conversions, user-defined
functions and commands, which before now you
had to buy disk drives to get!
Supplied on cassette with manual £39:95 + 50p
p&p
A. J. HARDING
28 Collington Ave, Bexhill, E Sussex
Tel: (0424) 220391
@ Circle No. 198
The sophisticated Disk Operating System is disk-
resident, which allows for future DOS-enhancements
without hardware alterations. PDOS supports multiple
file handling, allocating disk space dynamically to
each as and when necessary. Any file may occupy
from 1 to 600 sectors as required, at up to 16 non-
contiguous locations on the disk, PDSO may be used
alone, or within a BASIC program and offers user-
specified password security for any file. Multiple
access-modes simplify BASIC program construction.
Novapac duai-disk system complete with PDOS and
BASIC demonstration programs on disc £950 + VAT.
Available from the manufacturer or selected dealers.
Terms: 50% with order, balance on delivery.
Full cash with order is subject to 5% discount.
VAT-FREE Export arranged (Must be shipped by us).
47 Ridgeway Ave,
Coventry
Tel: (0203) 417761
@ Circle No. 199
PRACTICAL COMPUTING July 1979
ee ee |) editatlonsmy
DID YOU read the results of the Practical
Computing Christmas competition?
Cleaning-up oil slicks, dieting for diabe-
tics and re-creating historical episodes in
the classroom were only a few of the
ideas submitted; and I would be willing to
bet that there were other really good |
ideas doomed to oblivion simply because
they didn’t win.
The other day I was chatting to a
doctor and a naval engineer about pros-
thetics. The ones we were dreaming up
were hands. There are two main problem
areas in the design of a useful artificial
hand, the power supply and the control
system. The most sophisticated modern
ones use compressed gas for power and, |
while it is far from convenient, it can do
the job pretty well. Yet, the only word to
describe-the contro] is crude and it was
this aspect that we were discussing.
Most generally-available prosthetic
hands rely on muscular movements in
other parts of the body — typically the
upper arm and shoulders - to provide
both power and control. The nett result is
that to light a cigarette can involve
expenditure of considerable amounts of
energy, aS well as producing movements
reminiscent of a circus contortionist.
As it happens the nerves supplying a
missing hand are still intact over most of |
their course from brain to limb and are
hard at work trying to control the non-
existent extremity. In addition, they are
conveniently firing-out pulses of real live
electricity which can be detected easily
with little more than a good amplifier and
filter arrangement. Until now most ideas
| of linking nerves to transducers have
involved microsurgery at the nerve end-
ings, as well as a need for wires physically
to cross the skin barrier.
What we wanted was a receptor system
which could be implanted anywhere in
by Nick Laurie
who specialises in
popularising high technology
the general region of the nerves con-
cerned by any competent surgeon and
what we evolved was a simple web of
wires, each linked to an op-amp and
feeding its signals direct to a microproces-
sor, which could then do all the decoding
necessary to turn these signals into some
sort of sense.
The CPU chip, complete with op-
amps, a little memory and one or two
other things could, we decided, be
packaged in such a form that the owner’s
blood supply could pass right through it | me.
To catch a good idea
to help dissipate the odd couple of watts
of heat it gave off.
Extending ourselves further, we real-
ised that with a power requirement of
only a few hundred milliamps at around |
five volts we could bury a few square |
centimetres of thermocouples up the arm
to give a completely self-contained unit
needing no batteries, radioactive sources
or anything else.
As a final step we had to cross the skin
barrier, but with the aid of any one of a
dozen or more transducers ranging from
LEDs to Hall-effect semiconductors, we |
reckoned that that problem qualified as |
minor.
My doctor friend could see nothing
wrong with the idea; the naval engineer
reckoned he could construct the hand
quite easily — powered by compressed gas
— and I could see nothing over-difficult
about the computing side of things.
So why won’t we be seeing the bionic
hand in use this year? Are we really
doomed to a sort of electronic voyeurism,
watching a never-ending stream of appli-
cations being discussed while the best we
can do is reach out and occasionally grab
one for further development while the
rest of them slide off into oblivion?
I don’t pretend to know the answer,
but if you do, feel free to write and tell
bs
CAMBRIDGE COMPUTER STORE
We can help you select the right system for your applic-
ation. Here in Cambridge your choice won't be limited —
we'll demonstrate as comprehensive a range of microcom-
puters as you'll find anywhere in the U.K.:
WATCH THIS SPACE
for announcements
TANDY TRS-80
COMMODORE PET
APPLE II
N-S HORIZON
CROMEMCO
SORCERER
SUPERBOARD II
NASCOM-1
Where possible we deliver off-the-shelf. Our stock also
includes a vast range of electronic components as well
as computer books and magazines.
The store is open 6 days a week from 9—5.30 with demon-
stration systems always in operation. We offer a professional
standard of advice and after-sales support and we're ready
to discuss your application any time.
NEXT MONTH
regarding new
5-100 CARDS
from Europe’s S-100
bus specialist
LEENSHIRE LTD
13 Cathedral View,
Winchester, Hants.
CAMBRIDGE COMPUTER STORE
1 Emmanuel Street, Cambridge (0223) 68155
PRACTICAL COMPUTING July 1979
@ Circle No. 200
Tel: 0962 3675
@ Circle No. 201
107
‘t08
CADDIS (COMPUTER SYSTEMS) LTD
Suppliers of Microcomputers in:
% EDUCATION * SCIENTIFIC
% ENGINEERING %* COMMERCIAL
% PERSONAL (HOME) COMPUTING
WE OFFER:
1. A complete service for Commodore
including:
PETs
* Demonstration
% RS232C & Current Loop Interfaces
* Parallel 1/0 Interfaces
* Analogue I/O Interfaces
% User Port Teaching/Diagnostic Unit with
' Software
% Printers
% Memory Expansion Units
*® Protective Dust Covers
72-74 TRINITY LANE
HINCKLEY, LEICS.
HINCKLEY (0455) 613544
®
Sooo”
e
Hy
. Special Interfaces and Software designed
to your requirements
. Complete range of Petsoft Games, Busi-
ness and Education Programs
. Compucorp 600 Series Computers. Ideal
for larger companies and Estate Agents
* * * STOPPRESS * * x
4& 8K PETS @ 10% Discount on all orders received
during July!
@ Circle No. 202
WE TAKE OVER WHERE TANDY LEAVE OFF
We work exclusively with the TRS-80 because, as Consultant Engineers, we believe it to be the best
MICROCOMPUTER on the market, in its price range and, with our engineering skills and applications, it’s
getting better all the time!
LOOKING FOR A WORD PROCESSOR?
Have a look at the OPTRONICS system first, you could
save up to 50% against a competitive unit and ours
comes complete with a very fast and powerful. computer,
FREE!
Our word processor comes complete with a 12in. Video
Display
Up to 48K of RAM (for writing very lengthy script)
Full-size QWERTY keyboard
Up to four mini-floppy disks {or 8in. if you really need
them)
Wide choice of printers to suit your application
Upper and Lower case operation
Plain and pre-printed paper to your requirements
Operator training courses
System is controlled by the famous ELECTRIC PENCIL
software
Complete system guaranteed
50 Holly Road,
Twickenham, Middx.
Tel: 01-892 8455. Visitors by appointment
TRS-80 COMPUTER
Keep up to date with the TRS-80 COMPUTING newsletter
and SOFTSIDE magazine. We are also the U.K. dis-
tributors for CLOAD cassette magazine.
We are the exclusive U.K. distributors for Small System
Software and we keep most of their products in stock. The
TRS-232 is made by us in Twickenham, under licence but
our model includes a screen print facility.
They have just introduced CP/M for the TRS-80!
We hold a complete range of the amazing RACET
COMPUTES software!
We have a large stock of Dr. David Lien’s BASIC
HANDBOOK now at only £8.00 plus 50p p&p.
We also have the new MICROPOLIS TRS-80 DOS in stock
complete with a lin. thick manual!
Ask us about NEWDOS and NEWDOS+
We are about to introduce to the U.K. a new range of mini-
floppy disk drives with faster than current access times, at
a very competitive price!
We are expanding our business programs to meet the
ever increasing demand.
@ Circle No. 203
PRACTICAL COMPUTING July 1979
June
@19-21 International Microcomputers Minicomputers Microp-
@26
@29
rocessors. Venue: Palais des Expositions, Geneva,
Switzerland. The Exhibition will be displaying computers
- mini and micro - peripherals, components and services
from more than 100 international companies. The
technical conference is designed to provide an exchange
of applications, development and design technologies in
many areas of the industry. There will also be two ICS
Advanced Technology courses, run simultaneously —
Microprocessor Applications Development and Small
Computing Systems. Technical sessions and courses will
be in English only. More information from Kiver
Communications, S.A. (U.K. branch office), Millbank
House, 171-185, Ewell Road, Surbiton, Surrey, Tel: 01-
390 0281.
Microprocessor Seminar for Non-Electronic Engineers.
Venue: Manchester. One-day seminar for mechanical
and production engineers, supervisors and managers in
industry. Fundamentals explained, demonstrations, ex-
amples of applications and discussions. Attendance
limited to 10 people and the cost is £30 per delegate.
More information from Mektronic Consultants, Linden
House, 116, Rectory Lane, Prestwich, Manchester, M25
SDB. Tel: 061-798 0803.
Computers in Small Businesses. Venue: London. This
one-day course introduces guidelines for organisations
taking their first steps towards computerisation. It is
designed for the first-time user and assumes little
knowledge of computer techniques. The course costs £50
including lunch and light refreshment. Highly recom-
mended for those about to enhance a business with a
computer. More information from Course Registrar,
MSS Computer & Business Consultancy Ltd, MSS
House, 49 Chapel Road, Worthing, West Sussex.
Introduction to Basic Programming. Venue: Lecture
Room, Sumlock-Anita House, London, EC1. A three-
day course which will continue on the following two
Wednesdays. It goes through various elementary stages
such as explaining what a program is, to file structures
@5-7
@10-13
@23-25
and applications packages. Full course fee is £90 plus
VAT. Sumlock-Bondain advises early booking as only 12
places per course are available. Tel: 01-253 2447.
The 1979 Microcomputer Show Incorporating The DIY
Computer Fair. Venue: Bloomsbury Centre Hotel,
London. Essential for all computer freaks. This year
there will be a record number of exhibitors who will bring |
all the latest microcomputer equipment to the heart of
London. Entrance fee £1. For more information, see our
seven-page guide, which tells you all you need to know
about this event.
International Word Processing Exhibition and Confer-
ence. Venue: Wembley Conference Centre, London. |
Those who are considering buying a word processor |
could do worse than go to this comprehensive exhibition.
All you ever wanted to know about the subject will be |
available in the form of literature, demonstrations of all |
the latest equipment, and a two-day advanced confer- |
ence, and special-interest, half-day seminars. Admission
is £2. More information from BETA Exhibitions,
Business Equipment Trade Association, 109 Kingsway,
London, WC2.
Advanced Basic. Venue: London, EC1. This three-day
course is a follow-up to the Sumlock-Bondain Introduc-
tion to Basic Programming and is intended for those who
have taken one of the previous courses or have a ground
knowledge of the language. Full course fee is £130 plus
VAT. More information from Sumlock-Bondain Ltd.,
Sumlock-Anita House, 15 Clerkenwell Close, London,
ECl1.
September
@18
Microprocessors is a two-day seminar at the Cafe Royal,
London, organised by Informex in association with the
Institute of Data Processing Management. Speakers
include experts from the major semiconductor com-
panies. Cost for the two days is £78 plus VAT, which
includes lunch and refreshments for both days. Contact:
Jan Clarke, Informex-London Ltd., 61, Harland
Avenue, Sidcup, Kent. Tel: 01-300 0380.
EXIDY SORCERER 16K
SORD M100 ACE
PLOTTER
COMPUCOLOR
COMMODORE PET 4K
Complete Computer Systems
AFTER A YEAR’S EXPERIENCE AS - THE FIRST MICROHIRE COMPANY —- CCS HAVE EXPANDED INTO
SALES AND PROGRAMMING* DIVISIONS
CCS Microhire
CCS Microsales
FREE CASSETTE UNIT WITH 32K M/Cs
16K £970 48K
8K+DISC+CRT
£460 8K
16K £675 32K £795
£750 32K £850
price on application
£690:
£1290
£1370
£550
We have drawn on our experience of a BIG range
of machines to make up a Sales List consisting of
machines that represent the BEST in — VALUE
FOR MONEY - EASE OF USE - AND RELIABILITY
CCS MICROSALES
22 WESTSIDE
TEL: 01-444 7739
Letchworth 73301
68 FORTIS GREEN
LONDON N2
Still
the Leading Microcomputer
Hire
Company with the best range of equipment:
Apple Il; PET; Exidy Sorcerer; SEED System
One/MSI 6800; NASCOM/MICROS; Research
Machines 380Z and Tandy TRS-80.
Send for our NEW PRICE LIST giving the most
attractive prices yet. Don’t forget our ‘““THREE
WEEKS FOR THE PRICE OF TWO” OFFER
(From July to September).
Write to address below, or to London for
particularly urgent enquiries.
CCS MICROHIRE
FREEPOST
LETCHWORTH
HERTS SG6 4YA
* CCS MICROPROGRAMWS are actively looking for more programs to add to their range. Even if you
want to market your own systems, letting us know can generate more sales for you. If you have any
programs at all DON’T SIT ON THEM - TELL US.
Business and Technical systems First Please: Games — later. Write giving details to either of the
above addresses.
PRACTICAL COMPUTING July 1979
@ Circle No. 204
109
a PROGRAMS
Now
PETACT BUSINESS SYSTEMS
offer mainframe quality at micro prices:
SALES ACCOUNTING
provides all the facilities for maintenance of Sales Ledger, preparation of a dist of
outstanding balances and printing of statements.
, Cassette based system £225+VAT Disk version £350+VAT
PURCHASE ACCOUNTING
handles Purchase Ledger, preparation of a list of outstanding balances, printing of remittance
advices. “Cassette based system £225+VAT Disk version £350+VAT
Written by ACT’s own software team, each package handles 200 accounts and 800
transactions in memory at once giving true realtime operationona 32K PET and printer (typical
cost £1,350+VAT). Alternatively the disk-based version may be used with the addition of a dua]
mini floppy drive (price £740+VAT).
Other PETACT BUSINESS SYSTEMS 7
include: Invoicing, Payroll, Stock Control, Nominal Ledger, and Management Information wg
Ae
, 2D
Send for a free copy of our new 16-page catalogue. It contains details over 150 programs from £3 to £375. covering Business Packages, SS e?
Programming Aids to help you make the most of your PET and some super Games to play with it. Here are just a few examples: Ya we
S ©) Kv
TRY THESE PROGRAMS ON STAND 14 AT THE MICROCOMPUTER SHOW
OR AT YOUR NEAREST PET DEALER Prices include VAT
Addressbook £6 Hotel Finder £5 : Program Merger £8
6502 Assembler/Editor £25 Linear Programming £8 Sales Analysis £10
Backgammon £8 ‘Line Renumber £8 Statistics £7
Bridge Challenger £10 Mailing List £15 Super Startrek £8
Civil War £7.50 Micro Chess £14 Tax £8
Data File Handler £12 Music £10 VAT Pack £17.50
Discounted Cashflow £8 Payroll £25 Word Processor £25
Estate Agents Pack £25 Percentage Costing £49.50 76 Common Basic Programs £15
Graphics Package £12 Pet Basic Tutorial £12 :
For full details of these and the other cassette and disk programs in our free catalogue. complete the Ve
coupon or ring us.today. We also accept credit card orders over the telephone. tah
¢¥
Recommended by Commodore y ra :
--Spacianate in 7
personal computer e
programs, Ja @ :
4
5-6 Vicarage Road, Edgbaston, Birmingham B15 3ES. 4
Tel: 021-454 5348 Telex: 339396. 7“ ro
Petsoft A member of the ACT Computer Group. ie
Ny
PET js the trade mark of Commodore / .
® Circle No. 205
110 PRACTICAL COMPUTING July 1979
ROSTRONICS Computer Centre can scarce- |
ly be described as off the beaten track.
The shop is sandwiched between a
photographer’s studio and an undertak-
ers in Wandsworth High Street, in south |
London.
Such a location is evidently good for
the microcomputer business, though, as
Rostronics has sold a steady 15 to 20
systems a. month since opening in
January.
This shop is owned and run by its three |
directors, John Barton, John Pendreich
and Rhoda Battersby, who decided to
specialise in selling Tandy systems.
Barton spent a year looking at all the
equipment available on the market and
settled on the Tandy “because it offered
best value for money”.
Critical
Like many people, he is critical of the
way Tandy sells computers through shops
which do not provide what he considers
adequate software and support.
‘Specialist in computer business
machine systems’ reads the shop letter-
head and Rostronics is orientated firmly
towards selling commercial systems. It is
not really a hobbyist shop, although they
are catered for. Barton had his own |
business printing commercial stationery |
for a number of years; when he became
interested in micros he soon perceived
the potential for dealing with paperwork.
“Within a couple of years a!l businesses
with a turnover of £50,000 will have a
micro. Everyone. will have one, so why
not sell them and do the job properly?”
To do the job properly, Rostronics
writes its own software and provides its
own engineering service. The latter has
become so renowned that Tandy owners
telephone from all over the country,
Rhoda says, for help and advice. The
PRACTICAL COMPUTING July 1979
‘Selling
properly’
aim of
Rostronics
shop employs a full-time engineer and, if
necessary, can call upon another four
specialist engineers — moonlighting from
leading computers manufacturers, who
can afford to employ the best.
Repair service
Rostronics is very proud of the mainte-
nance contract it offers. Under the terms
of the agreement, Rostronics guarantees
to replace an item or repair any fault ona
business system within 24 hours of
receiving the call.
For that service the user pays 15
percent of the cost of the system per
annum; a business system will cost
£2,000, so the maintenance agreement
would be about £200 pa. This apparently
appeals to schools, which are only too
conscious of the effect sticky little fingers
might have on the school micro.
Rostronics is very particular about the
equipment it sells. Everything is tested
thoroughly before it leaves the shop and
only suppliers with a large maintenance
force to be called upon receive orders
from Rostronics.
The shop also tries to supply anything a
| customer may need. “if someone is to|
| have a business system from us, we aim to
have everything they need, down to the
printer ribbons”.
Software is written in-house; off-theé- |
shelf packages available include ac-|
counts, inventory, cash registers, and |
sales analysis, as well as the well-known
Electric Pencil word processor from the
States.
“Our word processing system’’, Barton
says, “is probably our strongest selling
point”. The Rostronics word processing
system comprises a TRS-80 plus the
Electric Pencil software and a daisywheel
printer. The printer is a Canadian
machine, manufactured by Alain Sapper,
and Rostronics is the sole importer at the
micro end of the market.
Rostronics can also supply continuous
stationery and business forms. ‘‘There is
no Other system on the market’, Barton
claims, ‘‘which will give you, at that
price, full screen-editing facilities’.
About 10 word processing systems have
been sold to date and, of course, the
customer, receives a computer as well.
Tandy shops sell two kinds of printers;
Rostronics sells three — the standard |
friction-feed and tractor-feed line prin-
ters plus the Teletype 43 and the Alain |
‘Sapper daisywheel. Rostronics buys its |
Centronics printers directly from Cen-
tronics and can thus sell them for less |
than the Tandy price.
System desk
Mail order accounts for a large amount
of Rostronics business and it is from all
over the world. ‘“‘We even have custom-
ers in Bahrain who telephone orders”’. |
“We are always looking at new pro- |
ducts appearing in the States”, Barton
says, ‘‘and we also have our engineer
working on some 8in disc drives” — from
Tinker Toy, Shugart and Micropolis.
A Rostronics-designed system desk is
about to go into production. The desks,
available through Tandy shops, are con-
structed to accommodate the Shugart
Micropolis drives in this country and they
do not fit the desk.
So Rostronics is building desks which |
will hold either Shugart or Micropolis
disc drives. The desk will also have a line
filter to protect the drives from fluctua-
tion in the electric current, and a power |
supply which will box the eight wires |
which straggle from the average config-
uration.
With a view to taking a second machine
on board, Barton has been looking
around the market again. ‘“‘The most
likely candidate is the ITT 2020; it has
good software and is cheaper than the
Apple”’.
Rostronics is in no hurry to adopt
another system, though. As Barton
points out, “Tandy has sold so many
systems that people will be looking for
Tandy software and hardware for a long
time”’. |
111
WHY BUY A
MICRO-COMPUTER FROM
PHETALEGE sevice tro.
BECAUSE
1) Established company trading since 1971 7) We can arrange finance
2) Electronic servicing is our speciality 8) We offer, after the three-month warranty, a
, service contract for £69°50
3) We have in house programmers/systems
analysts 9) You benefit from our experience of having
4) Weh , : sold over 150 micro-computers to industrial,
ee rece neerS educational and business, personal users.
5) We will demonstrate the PET at your 10) We specialise in programs and interfaces for
Pees weighing applications for average weight
6) We can customise the PET to your control and counting etc.
requirements
8K £550:00 + VAT. All ‘PETS’ sold with a Basic Tutorial Tape
16K £675°00 + VAT.
32K £795:00 + VAT.
New Lar
£ arge In our showroom we sell
eae ee 2 ee Books, Programs etc.
Also available:
24K Memory Expansion Boards (disk-compatible)
only £320 +. VAT
PET-compatible dual floppy disk unit
with advanced operating system
only £840 + VAT
Large Extension Keyboard for the PET £89:50 + VAT
Telephone for complete system prices.
Wide Range of Printers Available.
If you require any more information or demonstration regarding the PET 2001/8 or any associated
equipment, programs, etc., please contact Mr. P. J. A. Watts or Mr. D. W. Randall at:
Shop at:
PETALECT ELECTRONIC SERVICES LTD PETALECT
33/35 Portugal Road, Chertsey Road,
Woking, Woking,
Surrey. Surrey.
Tel. Woking 69032/68497 Tel. Woking 20727/23637
@ Circle No. 206
112 PRACTICAL COMPUTING July 1979
ees Computabit sama
BY USING the amazing collection of
graphics symbols on the Commodore Pet,
it is possible to set up a sequence of logic
operators which increase the screen size
from 40 characters wide by 25 deep to an
apparent 80 x 50 plottable points.
The characters used for this Double
Density Plot (DDP) are contained in
by A Clark
table 1 in'the sequence required for the
routine — the importance of this particular
order will be apparent later.
Say the new co-ordinate system has its
j origin (0,0) at the bottom left-hand
corner of the screen, giving maximum
values of 49 and 79 for Y and X
respectively. A normal-sized blank
screen character can then be considered
as divided into four possible DDP points:
DDY odd Cc B
DDY even D A
‘ DDX DDX
even odd
If you know the screen position (DDY/
| 2, DDX/2) and whether X and Y are odd
or even, the character required can be
found from table 1.
If A was to be filled (DDY even, DDX
odd), the character used from table’ 1
would be number 2; if C, we would use
character number 4.
A problem arises when we want to plot
a character at A if the block already
contains one or more DD points.
The method used in my subroutine is to
construct a byte whith the four least
significant bits representing the four
possible quarters of the character square.
So originally the byte would be 0000/0000
for a blank. ‘4
If we consider bit 0 to represent-A, 1 to
represent B, 2 to represent C and 3 for D,
the byte would change to the following
values (U) and configurations when each
corner Only is filled:
Position Byte Value Y x
A 0000/0001 i Even Odd
B 0000/0010 2 Odd Odd
Cc 0000/0100 4 Odd = Even
D 0000/1000 8 Even Even
As can be seen from table 1, there are
16 possible arrangements for A,B,C and
D, ranging from a blank square to a
completely filled-in square. There are
also 16 possible values of u if the four
Most significant bits remain constant.
It is now possible to show why table 1 is
PRACTICAL COMPUTING July 1979
Double density
plotting on Pet
arranged in that particular order. If we |
want to add B to a square which already |
contains A, the result and value of u must |
be 3 (bits 0 and 1 set); from table 1 it can |
be seen that when u is equal to this
number, the result is a vertical half- |
square, which is correct. This rule follows |
for all the other combinations. Try a few.
Strictly speaking, it is not correct to |
add the values of the bytes together. If
that quarter is already occupied the next —
bit will be set by a carry rather than the |
correct one remaining. For example, if B |
is to be re-plotted one would have added:
0000/0010
0000/00 10
0000/0100
which results in C being set rather than B
remaining. This problem of over-plotting
is Overcome by using the logical OR
rather than adding. Each bit in turn is
compared and if either bit is set to one,
then the result is set to one. So the
example becomes:
0000/0010
0000/0010
‘or’ 0000/0010
(continued on next page)
Table One
4B
significant
eeadtes | Value
tba | stent “ho Med UD J otha) | A
SNANAAANAAAAAAAAAARAARAAARAAAARAARARAARAAA RRR
>
NNNANNANAAARAARAAAARAAAAAAAAAAAAAAARARAANRARRRRN
TRS-80
SOFTWARE
SOME EXAMPLES
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STARTREK 111
ELECTRONICS 1
INVENTORY
FINANCE 1 f£ 6:50
ASTRONOMY 1 £ 6:50
MICROCOMPUTER
APPLICATIONS
11, RIVERSIDE COURT,
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RG4 BAL.
£37-50
£10-50
£ 6:50
£13-50
ANNANARAAAAAAAAAAARAAAARAAAAAAR ARERR ESSA SS ESEN
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Kee
SYSTEMS &
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We supply complete small
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instruction in the use of micros.
Windmill Rd. Sunbury,
Middx. (tel) 09327 86262
Telex 928185
@ Circle No. 208
TRS-80 LEVEL I!!!
This addition to LEVEL II loads in
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All this for £15 + 50p for
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A few Olivetti Teletypes for sale
at £250 each — easily connected
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For more details send to:
Jake Commander, 305,
Brownfield Rd., Shard End,
Birmingham B34 7EA.
NS
@ Circle No. 207
Za Arr ~~nn~~~~nnranrrrnnrdrcnrrrnrnrrnrdiQQQrrQr rrr Qn
@ Circle No. 209
113}
* PETOFFER x
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Demonstrations and immediate
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Capital Computer Systems 29-
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Tel 637-5551. The agents for
Commodore Pets and Bytronix
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@ Circle No. 210
ANDREWS COMPUTING LTD
Programs for minimum Nascom-t
—Fruit Machine Game @ £4:00
—Submarine Chase Game @ £400
—Game of Life @ £4:00
—Minefietd Game @ £450
—Program for extended NASCOM 1
—Renumber Basic program @ £8:00
All supplied fulty documented with listings
on 8-Bug, T4 or Nasbug format
Cassette tape.
C20 cassettes (inc. tib,
cases) 5 @ £2°40
10 @ £440
Machine code, Assembler for Basic coding
forms. £1°60 each pad (approx. 180 sheets).
Add 35p for P & P, all prices include VAT.
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3
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MICROCOMPUTER
HIRE AND OTHER
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Nascom, Horizon, Apple I,
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CEUDIULOAATOUDGANOVAUOGLODOUEUTONATEDOGGTOUOOEIVOUGUUSORGUAOGEUOEOUSOUDANEDOEOGOSIEEIT
Delivery and collection will be free in
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available.
Promglow Ltd, 30 City Road, London
EC1. Tel: 01-368 9002.
@ Circle No. 213
114
(continued from previous page) —
which leaves us with bit one set and no
carry to bit 2.
At this stage, look at the preliminary
flowchart for the subroutine. This routine
can be constructed in Basic in about five
lines by PEEKing and POKEing at the
screen; but if we include checks for valid
DDP co-ordinates as well as the facility to
erase squares, the plot routine length
doubles.
That is not excessive use of memory by
any means but the time factor becomes
important, especially on 3D plots. The
obvious answer is a machine code routine
for which a disassembled listing is given
at the end of the article.
The first problem to be overcome in it
was the passing of three values to the
subroutine by the USR function. The
number passed to the machine code is
converted to an integer in locations $B3
and $B4 by subroutine $DO0A7. The
method employed was to place the DDY
co-ordinate in the most significant byte
($B3) by multiplying by 256 and leaving
the X co-ordinate in the least significant
byte, $B4.
The third variable, whether to plot or
erase, is controlled by setting bit seven in
the least significant byte if an erase is to
be carried-out. So typical USR com-
mands would run as follows:
Table Two
TRANSFER CO-ORDS
AND SEPARATE
O<X<78 O<¥<79
FIND SCREEN LOCATION
CALCULATE U FROM
ODPX* ¥
Z = TABLE LOCATION OF
SCREEN CHARACTER
‘OR’ U4Z@ ¥
Y" TABLE CHAR’ TO SCREEN
10 W = USR odie ..plots at DDP
20 W = USR (128+ Y*256+X)...sets bit
seven and erases DDX,DDY
Among other ideas incorporated, I
decided to transfer back from the sub-
routine into W the value of the screen
character at X, Y before alteration; and if
either DDX or DDY were invalid - not
on the screen ~ USR would return with
W = 1024.
Glitchless plotting is also featured by
using a subroutine ~ WAIT in listing -
which stops the machine code looking at
or writing to the screen at the wrong:
time, which means during a screen
refresh cycle.
Cassette offer
Remarks contained in the program
listing explain the sequence of events
simply, so a detailed flowchart is not
required. If anybody has any comments
or improvements on my first attempt at
machine code, I will be only too grateful
to receive them.
For those who would like double
density graphics and who do not yet have
the experience necessary I will be happy
to supply a cassette tape which loads the
routine automatically into the second
cassette buffer, for a nominal £1.50. The
only line required in your program would
be:
10 POKE 1, 58 : POKE 2,3
The program which plotted figure 1.
follows:
1 POKE i, 58: POKE 2,3
2. PRINT CLEAR PAGE"
3.) EF = 0: Ti = 3: T2 = 99: T3 = 4: T4 = 1521: TS = 23: T6 =
6.7: T7 = 40: TB = 256: T9 = 24:V =
$1 = 79: $2 = 44: $3 = 48
DEF FNA (Z) = Tl * EXP(-Z*ZT)
FOR X = -T2 TO T2
L=O
¥1 = 13" INT (SQR(T4 - X * X)/T3)
FOR Y = Y1 TO~-Y} STEP - T3
Z = INT (TS + FNA (SQR (XX + Y " Y)) — 16°, Y)
IF Z < =L THEN 190
L=Z
W = USR (X + T7 + T8* (Z-T9)
NEXT
NEXT
FOR X = ~T2TOT2
Z = INT (75 + FNA (X)) j
FOR L = TSTOZ |
W = USR (X + 17+ 78° (J-TY))
NEXT
NEXT
PRINT "CLEAR PAGE”
FOR i =O TOT2:FORJ = OTOI:
W=USR(I+(T3+V+J)°TB)
W=USR(S1-I+(S2-1)°T8): NEXT: NEXT
PRINT “CLEAR PAGE”
FOR J = O10 Si: FOR | = O TOS3 STEP 2:
W = USR (J + 1°78)
W = USR (SI-J + (1+V) °T8)}: NEXT: NEXT
GOTO2
Happy plotting, and the address for the
tape is: A. Clark, 107 Haydon Close, Red
House Farm Estate, Gosforth,
Newcastle-upon-Tyne NE3 2BZ.
PRACTICAL COMPUTING July 1979
Disassembied machine code listing
0334
03FB
03FC
03FD
03FE
20A7DO
ASB4
LABEL:
EVEN 1:
LAB 1;
EVEN 2:
LAB2:
LABL:
LABL I:
LAB3:
ERRi:
ERR2:
LAB 4:
Loop,
LABS5;
WAIT:
ERR:
TABLE:
PRACTICAL COMPUTING July 1979
JSR DOA?
LDA B4
BMI Erase
LDA# CC
IMP Label
ROL B4
LSR B4
LDA# CA
STA O3C8
LDA B4
LSRA
STA B2
BCC EVEN L
LDA# 03
IMP LAB 1
LDA# OC:
STA BS
LDAB3
LSRA
STA Bi
BCC EVEN 2
LDA BS
AND # 06
JMP LAB 2
LDA BS
AND # 09
STA BS
LDAg# 18
SEC
SBC Bi
BMIERRI
STA BIL
SEC
SBC # 19
BPL ERR2
LDA4# 80
STA B4
LDA¥# 00
STA B3
LDY Bi
BEQ LAB3
ADC# 2B
BCC LABL !
INC B4
cLe
NOP
NOP
DEY
BNE LABL
STA B3
LDA B2
BMI ERR
STA B2
SEC
SBC¥# 28
BPLERR
LDA B3
ADC B2
BCC LABS
INC B4
STA B3
LDY # 00
LDX# OF
JSR WAIT
LDA (83), ¥
TAY
CMP TABLE, X
BEQ LABS
TAX
JSR WAIT
LDA TABLE, X
LDX# 00
STA (B3,X)
LDA # 00
IMP D278
LDA E840
EOR # 20
AND# 20
BEQ WAIT
RTS
NOP
NOP
LDA # 04
LDY# 00
SMP D278
: Converts argument to
integer in B3,B4
: LSB {x coord)
: Checks for bit 7 set
: Alters jump address in 0307
: Removes bit? from B4
: Alters jump address in Q3C7
‘Divide DDP X by 2 togve screen X
: Screen X into B2
> DDP Xis odd, V = lor? =3
DDPX is even, V = 40r8 = 12
: V temp into BS
: Divides DDPY by 2
: Screen Y" into BI
: DDPY is odd, V = Zor 4
¢ Result is actual V
: DDPY is even, V = Lor 8
: Result 1s actual V
: Change screen origin to top of scree
: DDPY too large
: New screen ¥
> DDPY too smati
: Load (0,0) Screen ram position
: Screen hi
: Screen lo
: Find Y pasition in screen ram
: DDPX tao small
: DDPX too large
: Final screen ram positions
: Find character at X, Y
; Finds Character in X, ¥
:if no table character:-Blank
: Plot addition
: Variable Juovp: past or to erase
: Erase pot
: Plot on sereen
: Return with integer.to FLP
: Subrouune which waits for
a screens refresh
: ERROR MESSAGE (W = 1024)
- Returns W = 1024
: Character Table
6800 SYSTEMS
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£152°50 with full QWERTY keyboard.
NCU Board. This number cruncher using the
MM57109 is supplied with our own Basic style
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8K RAM (2114) and 5 or 10K PROM board.
This pcb is bus compatible with the above
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all prices without VAT and post
PLEASE SEND SAE FOR LEAFLETS
i] HEWART MICROELECTRONICS :
95 BLAKELOW ROAD H
MACCLESFIELD, CHESHIRE
@ Circle No. 214
hy
INTERFERENCE?
Our no wiring, plug in Suppres-
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£18 (inc. VAT, p & p)
BEYTS
LOGIC
Windmill Rd, Sunbury,
Middx. (tel) 09327 86262
Telex: 928185
@ Circle No. 215
fully assembled
burned in $100
Dyna-Byte
16K Dynamic RAM £198
16K Static RAM 250ns £271
16K Static RAM 450ns £266
32K Static RAM 250ns £506
32K Static RAM 450ns £470
80 »: 24 video terminal, just add key-
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Cable set for videoterminal £7-20
Postfree. Add 8% VAT toall prices,
S.W.C. Electronic distributors, P.O.
Box 30, London E.4.
@ Circle No. 216
115¢
TRS-80 Software
Our latest catalogue of over 50 titles
@ Games/Microchess, Startrek, etc.
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Send S.A.E. for our catalogue of level
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@ Circle No. 217
INTRODUCTORY
Special Discounts on:— Assorted
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Send s.a.e. for full Catalogue
ROMANE ELECTRONICS
64 Newlyn Drive,
Sale, Cheshire M33 3LE
@ Circle No. 218
NICOMTECH
Cornish and West Devon distributor for
the ITT 2020 and range of accessories.
Amateur radio software available for PET,
APPLE, 2020 and TRS-80.
European Distributor for MICROTRONICS
MORSE and RTTY software for PET and
Blank C10°2 etc. on sale.
Mailing services available.
Phone Nigel Huntley on (075-55) 2066.
Address: 212, St. Stephens Road,
Saltash, Cornwall.
@ Circle No. 219
RADIO SHACK COMPUTER OWNERS
TRS80
(Not to be confused with TRS-80 Computing)
PRACTICAL APPLICATIONS
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G-MAX RESEARCH CO. LTD
STATE RD, SUTTON, SURREY
TEL. 01-642 8971 (Nocallers please)
@ Circle No. 220
Real-time clock
for M6800 D2
DESIGNING a real-time clock for a micro-
computer development kit, factors like
the Motorola MEK6800 D2 should be
considered. Among them ~ is the system
clock stable enough for use as a time
standard? Is the MPU to be used for tasks
other than time-keeping, so that a
software-only solution is impractical?
Can the 50Hz mains be used as a timing
signal? Can the final choice of timing
signal be interfaced to the MPU with
minimum external hardware?
by Brian Wilkie
Motorola Semiconductors, East Kilbride
Assessing these in relation to a D2
microprocessor requires some apprecia-
tion of the hardware already in the kit.
@ The D2 uses a crystal oscillator at
614.4KHz which is divided down to
4,800Hz for use in a Kansas City
Standard cassette interface.
@ It has a hexadecimal keyboard and
associated debug monitor, which is
ideal for initial clock setting.
@ It uses six seven-segment LED dis-
plays for output of information. This is
ideal for time display, with the proviso
that they must be driven in a multi-
plexed mode by software, using one
PIA port as segment drives and
another — outputting only one bit high
at a time — for digit drives.
@iIt has provision for using two
MCM2708 EPROM. The one located
at hex address $6000 - the dollar
indicating hexadecimal notation — was
selected for this program, although it
could be altered easily to fit into the
RAM locations lqwer in the memory
map.
Nucleus
We can eliminate some of the options
in choice of time standard. The intention
of this program was to act as the nucleus
of a central heating controller, so a
software-only solution can be put aside.
Since six LED displays must be refreshed
at least 25 times a second — which means
150Hz - a 50Hz interrupt from the mains
would be too slow.
Fortunately, the designer of the D2 kit
used a 12-stage CMOS counter, the
MC14046, to divide down from the
crystal clock to drive the cassette inter-
face. The final stage of this counter
therefore has a 300Hz square wave which
is crystal-controlled and at an ideal
frequency for driving the LED display.
The only hardware modification neces-
sary on the D2 kit is to connect this
300Hz signal from U18 pin 1 to the user
PIA interrupt input CA1, U20 pin 40.
The flowchart and listing show a
program to turn this 300Hz signal into a
clock. Note that the initialisation puts the
start of the interrupt service routine into
location $A000, which is, in turn, re-
ferred to by the internal JBUG interrupt
service routine.
The interrupt service routine is short
and simple; such routines are difficult to
debug without professional equipment
and since the wait-for-interrupt loop has
its own software timer, the program can
be checked in the absence of an interrupt
signal.
The time is stored as three bytes of
packed binary-coded decimal informa-
tion, to facilitate the addition of alarm
and on/off time routines to the program.
Time is increased not by an increment
instruction but by an add immediate one;
this sets the half-carry flag for the
subsequent decimal adjust accumulator
to restore the number to BCD format.
Expanded easily
In normal operation, the software
enters a wait loop, checking continually
for the flag byte to be incremented for
zero, When this happens every 1/300
second the time counters are in-
cremented; if the displayed time has
altered, the new time values are trans-
lated into suitable format in the display
buffer locations. This facilitates changing
to other display formats, such as ASCII
for output on a VDU.
The software then calls a display
subroutine which converts one character
at a time to seven segments, using a look-
up table DIGTBL in JBUG and output-
ting it to all six LEDs in parallel.
Finally, a new digit is selected by
shifting the scan count mask SCNCNT
one bit left. At this point the program
returns to the waiting loop to await the
Next interrupt; extra routines such as
alarm time checks could, however, be
added here.
The software is organised so that even
if extra routines like this occasionally last
more than the three milliseconds between
interrupts, the IRQ service routine will
count the unserviced interrupts in the flag
register in memory, On returning to the
clock program, the time counter is then
incremented as many times as required to
compensate for missed interrupts.
PRACTICAL COMPUTING July 1979
cient and easily-expanded real-time clock
facility for the D2 kit. Its major problem
is that the clock circuit used in the kit has
no facilities for frequency trimming such
as is usually employed in electronic watch
This program provides a short, effi-
circuits. Those kits we tested in our
laboratory ran to within a few seconds a
day; this could be adjusted easily in
software ~— for example, by detecting
midnight and making the necessary ad-
justment in the software.
Real-time clock flowchart
IRQ
Inc flag in RAM
clear PIA
interrupt REQ
Increment
millisecond
counter and
clear flag
Add 1 second to
time counts
hrs, mins and
secs
Reformat time
into display
buffer
Call
display
subroutine
Get next digit
inc buffer pointer
fetch relevant 7
segment pattern
from DIGBTL
my |
5 millisec
backup timer
clear digit drive
send out new
pattern output
next digit drive
only one
interrupt
been
done
buffer
pointer past
Correct time
for missed
interrupts
Initialise next
digit drive +
buffer pointer
Shift next
digit drive
RTS
PRACTICAL COMPUTING July 1979
NORTH-WEST LONDON’S
HOME FOR NEW BORN PETS!
Why dash into town for your new Pet, when
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Our prices are lower than anywhere in the
U.K.
In stock now:
PET 2001 (8K, 16K, 32K, inc large key-
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Centronic Printers Extra Cassette Decks
Interfaces Oodles of Software
SOFTWARE TAILOR-MADE & WRITTEN FOR
INDIVIDUAL APPLICATIONS
Evening & week-end demonstrations & sales
Examine & purchase at your leisure
Just pick up the phone and make an
appointment
L & J Computers
01-204 7525
NOW!
3 Crundale Avenue,
Kingsbury, London, NW9
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OHIO SUPERBOARD
Computer on a board. 8K basic
in ROM _ keyboard, graphics,
cassettes interface. 2K monitor,
British TV interface, expand-
able.
4K RAM £275 8K RAM £315
Please send SAE for details
C.T.S., 1Higher Calderbrook
Littleborough
‘Lancs OL15 SNL
Tel. Littleborough
(0706) 79332 anytime
@ Circle No. 222 |
MICROTEK
COMPUTER
SERVICES
Agents for North Star Horizon.
Personalised software for small
business applications. Stock
control, accounting, estate
agents package, mailing list
programs.
50, Chislehurst Road,
Orpington, Kent
Tel 66-26803
evenings 0474-872630
@ Circie No. 223
117
BUSINESSMEN
DISAPPOINTED
IN TRS 80
Need expert software
and hardware advice to
get their machines
operational
BOX 113, EMG,
30 Heathfield Road,
Croydon, Surrey
@ Circle No. 224
B&B Consultants
THE CONSULTANTS FOR THE
NORTH WEST
“You can rent me for 10 pence an hour”
For further details please contact
B&B CONSULTANTS
: 124 Newport Street,
Bolton, Lancs.
Or Telephone: Bolton
(0204) 26644
@ Circle No. 225
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for
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168 Finchley Road,
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Tel. No: 01-794 0202.
Dealer enquiries welcome.
4
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PRINTER
BD 80’-COLUMN Matrix Printer
Parallel and RS-232 Interface Standard.
Pet IEEE Interface Undecoded £45
Pet IEEE Interface decoded £80
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CAMDEN ELECTRONICS
First Floor
462 Coventry Rd., Small Heath,
Birmingham 810 0UG.
021-773 8240
@ Circle No. 227
118
Kim Project —
Morse Code
Generator
This month’s Kim project shows the Kim-1 microprocessor in a dedicated
application as a Morse code generator.
BEFORE an individual is allowed to use
the amateur radio frequencies, a Post
Office test in Morse proficiency must be
passed. Having satisfied that require-
ment, the radio ham need never fook at a
Morse key again.
Nevertheless, Morse has many advan-
tages over the other forms of radio
transmission; the equipment required is
simpler and cheaper than that needed for
voice telephony, for instance, particularly
-| at the higher power outputs.
Reception is possible over longer dis-
tances and under less favourable cir-
cumstances, again requiring less sophisti-
cated receivers.
While it is a slower transmission
method than RTTY methods or voice
| telegraphy, it has the dual advantage of
being possible both to send and receive
Morse without any specialised equip-
ment. Further, the Morse code can be
generated automatically and it can be
received by machine as well.
Samuel Morse devised his code origi-
nally in 1832, basing it on the newly-
discovered properties of electricity and
electromagnetism. His initial design for a
| transmitter involved a series of projec-
tions shaped to form the code on
template ‘portrule’, which could be
moved under a contact lever to generate
the codes.
Shaped by hand
At the receiving end, an electromagnet
deflected a pencil over a moving reel of
paper; the wavy line on the paper would
then be deciphered and the message
could be read normally.
In succeeding models, the portrule was
replaced by the Morse key we know
today, each character being shaped by
hand. It was nearly 10 years before
someone realised that the dot and dash
made different sounds on the receiving
solenoid and that they could be under-
stood directly; so the writing receiver was
abandoned.
Morse code became very popular for
telegraph methods but in the 1920s, with
Baudot code teleprinters and the like, the
Morse code became less widely used.
Early radio transmitters provided an
excellent medium for it. The crudest or
the most sophisticated transmitters could
be used, albeit with relative risk of
electrocution, to almost equal effect.
Morse has all but disappeared for
telegraph transmission but it remains a
firm international standard for radio; and
the SOS signal has become the definitive
distress cali. ;
Each letter, digit, and punctuation
mark along with various procedural sig-
nals - like invitation to type, end of
transmission, error — is represented in
Morse code by a combination of between
one and eight dots and dashes. A dot is a
short period during which signal is
present, a dash a somewhat longer
period.
There is no specification as to how long
a dot should last - typically between one-
tenth and one twenty-fifth of a second —
but Morse transmission is defined in
terms of ‘dot’ periods. A dash is defined
as a period equal to three dots. The
spaces between dots and dashes of the
same character are equal to ene dot. The
space between one character and the next
is equal to three dots and the interval
between adjacent words is equal to seven
dots.
Post Office test
The Post Office Morse test specifies a
rate of 12 five-character words per
minute. A radio amateur, who must
transmit a call sign at the beginning and
end of each contact and at 15-minute
intervals during it, may send the call sign
either on telephony or Morse telegraphy
at a rate of up to 20 words per minute.
One of the applications of the automa-
tic code generator is to repeat the call
sign with a single key stroke. In fact, it
can be made to repeat any ASCII
character string in Morse, although the
full ASCII character set is not im-
plemented. Table 1 shows the various
ASCII characters with their Morse and
hexadecinial equivalents.
A subroutine to translate ASCII
characters into Morse equivalents may be
used in any number of ways. For inst-
ance, the program STRING retrieves
bytes successively from the Kim memory
and calls the subroutine CHAR to sound
the character as Morse, stopping when it
reaches a byte containing zero. CHAR
will convert an ASCII character in the A-
register into Morse and put it out on to
two of the user PIO lines.
PRACTICAL COMPUTING July 1979
es COMputabits
Unfortunately ‘consecutive’ Morse
characters have unrelated code represen-
tations. Whereas in ASCII code the
character ‘A’ is represented as $41 and
‘B’ as $42, the Morse is °.-' and *...’
respectively. So we cannot rely on prog-
ram code to generate Morse from ASCII
using simple rules. Because of this each
character has its corresponding Morse
representation in a look-up table ($026E-
$0357).
As each character is a different length,
there must be some way of determining
“where it begins and ends. An initial idea
was to store the ASCII byte with the
Morse characters and then search se-
quentially down the table until the
required code was found.
A more efficient and elegant solution
generates a second table containing the
addresses for the start of each letter, digit
and symbol ($0200-$026C). Each of those
entries is a two-byte address with the
letters and digits organised in ASCII
order.
Powerful feature
To find any particular Morse character,
for instance the letter ‘C’, the numeric
value of *A’ ($41) is subtracted from that
letter ($43 minus $41), showing that this
is the second letter (A is at zero).
Because each address is two bytes, this
result is multiplied by two, a single shift-
left.
One of the most powerful features of
the 6502 processor chip used in the Kim is
its indirect indexed addressing mode. In.
this mode any two consecutive bytes in
the first 256 bytes of memory may be
used as a pointer to some other location
in memory. Their contents then act as a
pointer to some other location in
memory, forming an operand to the
current instruction. There is an added
bonus that the current contents of the Y
register are added to the pointer before
the indexing is done.
Figure 1 shows that the process of
indirect pointer addressing is used twice
to find each Morse character. Consider a
call to the subroutine CHAR with the
ASCII character ‘C’ in the A-register.
First a jump to INTER is made; it
produces the three-dot inter-character
silent period. The parity bit, if there is
one, is ANDed out.
Next the character is tested to see if it is
a space ($20). If it is, a further six-dot
duration of silence will occur and the
subroutine returns. Since it is not, and
since it is greater or equal to ‘A’ (BCC)
and also less than ‘Z-1’ (BCS), the value
of ASCII ‘A’ is subtracted from it.
The shift left (ASL) multiplies the
result by two and it is loaded into the Y
register. The instruction LDA (LET), Y
loads the A register with the contents of
the location pointed to by LET offset by
the contents of the Y register ($4).
Looking at the start of the program shows
that LET contains the address of
PRACTICAL COMPUTING July 1979
LETTER (08200).
So location $0204 contains the low-
order byte of CHARLY, the Morse for
the letter ‘C’ ($74). The next byte, Y=5
($0205), contains the high-order byte |
($02). Those two bytes are transferred
into the
STARTC+1, employing the ‘zero-page,
X’ addressing mode to store the bytes.
The code starts at label C100. STOPC is,
loaded with the next two bytes ($0206
and $0207) containing the address of
DELTA ($0278).
Using this scheme, if STARTC is
loaded with the beginning address of one
character, then STOPC 1s loaded with the
start address of the next, irrespective of
the length of the Morse code.
Digits are handled in essentially the
same way, except that zero (0,$30) is
subtracted from the initial contents of the
A register, and the addresses loaded into
STARTC and STOPC are those offset
from DIGIT - the address of which is
stored in DIG.
Procedural and punctuation characters
are handled by testing for each in turn,
the code from label CS to label C15.
Whenever such a symbol is located the Y
register is loaded with the relevant offset
from SYMBOL, whose address is stored
in SYM. If the character was not found at
all, STARTC is loaded with the ERROR
>
character, eight dots ’........”.
Sound label
By the time the program reaches the
label SOUND, STARTC contains a
pointer to the first dot or dash of one of
the Morse characters LDA (STARTC),
Y with zero in Y loads either a dot or a
dash into the A register. If it is a dot, the
subroutine DOT is called; otherwise
DASH is called.
Instead of adding one to Y the next dot
or dash, a full 16-bit increment by one is
performed on STARTC. All 16 bits of
STARTC are compared with STOPC; if
they are equal, the subroutine exits. If
they are not, the new value in STARTC -
modified by the zero in the Y register -
points to the next dot or dash.
Subroutine DELAY ($00B0) is called
by both DOT and DASH. It uses one of
the internal timers provided on the Kim
board. DELAY will delay a period of
time corresponding to one dot; it will be
called three times for a dash. During a
dot or dash the microprocessor has to
produce a tone, which will appear on the
applications port PAO.
On PAI an on/off signal provides the
capability to modulate a transmitter or
external oscillator using a relay or transis-
tor switch, in piace of the Morse key.
DELAY is used for sounding the dots
and dashes as well as the silent space
periods; it has to act as an oscillator
during the sounded dots and dashes but it
must also be muted during the silent
periods. ,
(continued on next page)
locations STARTC and;
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120
(continued from previous page)
To obtain the oscillator function 21 is
loaded into the 64-microsecond counter
location C64D. The program then re-
mains in a tight loop for 1,334 micro-
seconds. After that the location OSC is
incremented, changing the least signific-
ant bit from zero to one or from one to
zero.
By loading this into the A register and
ANDing it with %00000001 the bottom
bit oscillates at 372Hz; during a tone
period this wili be transferred to PAO.
By ORing it with %00000010 the
second bit is always set and will be
transferred to PA1. Just before it is
stored into the output port PAO-7 it is
further ANDed with MASK. If MASK
was loaded with zero before calling
DELAY, DA is always loaded with a
cleared byte and DELAY is silent. On
the other hand, if MASK was loaded with
%00000011 then PAO oscillates at the
tate determined by the timer and PA1 is
set for the duration of DELAY.
The variable SPEED ($0002) contains
| the number of half-cycle timer delays
DELAY will perform per call. It is
initialised to $40. If this number is
reduced the Morse will be sounded
faster; if it is increased the rate will fall.
The number loaded into C64D to effect
the delay determines the frequency of the
tone; by changing this the pitch will be
altered. SPEED will have to be adjusted
to compensate for the rate change
caused.
Subroutine DOT will call DELAY
twice. The first time MASK will enable
the output channels and the program will
produce a tone for one dot period.
DELAY is called a second time with
MASK set to zero, so the program will be
silent for one dot period; this is the inter-
dot/dash spacing.
Subroutine DASH is almost identical
in operation, except that DELAY is
called three times in quick succession to
sound a dash. Subroutine INTER gener-
ates an inter-character delay, three silent
dots. Subroutine INIT must be called
before any attempt is made to use
DELAY; it sets the user peripheral port
PAO-7 to be an output device.
Four programs
These subroutines have been incorpor-
ated into four distinct programs. They are
given as examples and you will no doubt
find they do not match your particular
Tequirements exactly. The important fea-
ture is that CHAR will translate the
ASCH character passed in the A register
into Morse, at a rate determined by the
value in location SPEED. This includes
an inter-character delay. A space is
interpreted as an interword delay.
Setting-up the start address of the
program STRING ($0013) and pressing
the GO key on your Kim causes the
program to sound a string of characters
from memory in Morse. You will notice
that the start of the string is not
mentioned explicitly in the program;
instead, the indirect indexing mode is
used again.
A string of ASCII characters termi-
nated by a $00 byte is placed in any
consecutive locations in the Kim memory
space. The low- and high-order bytes of
the beginning address are then loaded
into the location BUUFER ($0000).
Note that the test string MORSE
TEXTO starts at the label TEXT. This
means that the text to be used may be
anywhere in memory and that it is data
locations, not program, which are altered
to show where a new string begins. Apart
from making the code somewhat tidier
this means that the program could be
blown into memory with no further
modification.
STRING sets the Y register to zero and
extracts the first byte of the text into the
A register. If it is not the zero terminator
it calls CHAR. Y is incremented and the
next byte is obtained by jumping to
STRG.
This will continue until Y overflows, in
which case it will start to repeat the first
256 byte of the message, or until a $00
byte is encountered, in which case it will
go into the tight loop ‘HERE JMP
HERE’. Use of the RESET button will
allow the string to be played again by
pressing GO.
This could be extended to play a
number of strings which could be called
with a little operating system, by using
the Kim-1 keyboard to form a Morse
‘jingle-machine’ for radio amateur use.
By retaining the indirect indexing techni-
que, the strings can easily be of varying
lengths and spread through the memory
wherever there is unused space.
Inconvenient
The second program KEYED ($002C)
initialises the port with INIT and then
alternates between the Kim-1 keyboard
fetch routine GETCH ($1E5A) and our
CHARI routine. The code will wait for a
character inside GETCH until one is
typed, return and then jump to CHARI.
CHARI is identical to CHAR except that
there is no inter-character delay; this will
be provided by the time to type the next
character.
Because GETCH simulates the serial-
to-parallel conversion of an ACIA device
in software, the program must return to
this routine before the next key is
pressed. This feature is somewhat incon-
venient; the user must predict the end of
the last Morse character and start the
next One just as it finishes.
By adding an ACIA - like the Motoro-
la MC6850 - and setting-up a circular
buffer to store characters if they are
typed too quickly, a more usable system
would result. Still, as it stands the main
penalty is slightly-increased inter-word
PRACTICAL COMPUTING July 1979
ees Computabits am
spaces and lost characters if the next is
typed before the last one is finished.
The third program CHATER ($0038)
sounds Morse characters at random. It
could be used for Morse code receiving
practice. Part of the Post Office Morse
test for radio amateurs requires candi-
dates to transcribe 36 words in three
minutes and 10 five-digit groups in one-
and-a-half minutes; four errors in the
words or two in the number test will
, result in failure.
A random code generator would not
represent a fair practice medium for the
test but could assist the beginner with
individual character recognition.
A pseudo-random number generator
($007A) places the next ‘random’ number
in a series into location RND ($000F).
The series is obtained by multiplying a
seed - in RND, which holds the fast
‘random’ number —- by 13. All but the
bottom eight bits are then discarded and
the result is incremented by one. Any
integer can be multiplied by a constant in
this way.
This program will sound any of the first
48 characters of the defined Morse set. A
‘random’ number in the range 0 to 47 is |
obtained by calling RANDOM and
ANDing off the top three bits in RND, to
produce a number in the range 0 to 31.
RANDOM is called again and this time
the top four bits are cleared, leaving a
number in the range zero to 15.
Adding together these two numbers
results in one in the desired range; Y is
loaded with this number multiplied by
two. This is then used as the offset from
LETTER, loading STARTC and STOPC
as before. Subroutine SOUND, which is
part of CHAR, does that and INTER
forms the required inter-character delay.
Three no-operation instructions are
placed at $0062 but they could be
replaced by a JSR PRINT routine call.
PRINT would print-out the character just
(continued on next page
Table 1: ASCII characers with hexadecimal and Morse equivalents.
ASCH
N<xsS<CHMDPVOZSrHA-- TOA NM. ODD
L
nn
* OBNOMAWH-O
w
a
——~ |
NO
fe)
PRACTICAL COMPUTING July 1979
’
MORSE
(any unspecified ASCH
character code}
.- (full stop)
.-- (comma)
{colon)
og . (question mark/
repeat misunderstood transmission}
.----. (apostrophe)
(dash/minus/hyphen)
(oblique)
(open bracket)
—.--~.- (close bracket)
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For further details ring (0482) 23146
@ Circle No. 235 |
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121
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122
Rees Computabits
(continued from previous page)
sounded on a terminal, so the user could
check the accuracy of transcription. Re-
member that you would have to translate
the 0 to 47 number into its ASCII
equivalent; a 48-byte long look-up table
is a possibility.
Test routine
The last program ALTERN ($0068) is
a test routine which sounds dots and
dashes alternatively.
All the programs are designed to be
exited from by use of the RESET key.
If you are a Morse code user it is
possible that the four demonstration
programs STRING, KEYBD, CHATER
and ALTERN will not match your
requirements exactly; but CHAR, INIT,
RANDOM, DOT, DASH, DELAY and
INTER are all complete routines and
could be embedded in a program of your
own construction in a vast number of
ways.
Sorting large files
A BUBBLE sort requires all data to be held
in the internal store. This is feasible with
small quantities of data but with large
files it may be impossible (insufficient
storage space) or expensive (reduction in
the number of programs running to
provide space).
On minis and mainframe computers a
different sorting technique is used; it util-
ises three or more files including the one
holding the source data.
Some microcomputers are not able to
access so many files at the same time but
if two are available, one for input and the
other for output, sorting of large files is
possible, though it may be somewhat
slow.
The example given used a bubble sort
with a 100-element array to form the
work area. The data is taken in small
quantities from one file, sorted and
output to the second file.
The data on the output file is in small
sorted sets and if the output data is sorted
a second time, the result would be no
different from the first. That is because
the work area is of a fixed size.
To overcome the problem, the data has
to be sorted using work areas of different
sizes. When the data is being transferred
from file A to file B, the work area is set
to the maximum size 100; when the data
is passing from B to A, the work area is
varied between 61 and 69.
The work area is allowed to vary to
avoid the possibility of the program
getting into a loop which cannot be
broken. Consider the problem where the
work areas are set at 100 and 60. Any file
having more than 600 items would be in
sorted in order up to the 600th and an-
other sorted sequence would start from
the 601st.
As the program stops only when the
whole file is in sorted order — and it never
would get into sorted order — the program
will run indefinitely.
When the program listed is running,
the user is informed as to which direction
the data is being passed by the symbols:
A > B Input A, Output B
A< B Input 8, Outpur A
This example us for a file of more than
300 items:
RUNNH
A>B
END OF RUN. SORTED BATA ON FILE B
READY
This printout is for the following file,
unsorted on the left and sorted on the
right:
TAKE IN PRINTOUT 3 HERE TAKE IN PRINTOUT 4 HERE
The records comprise Part Number
(characters 1-9), Price (10-15), and quan-
tity (16-20). The word END is used to
indicate the end of data.
Fixed format
To use the sort on records, the data has
to be assembled as fixed format. This
means that data has to be in a specific
place and of a specific type — alphabetic
or integer, for example and length.
It is not too difficult to alter the
program so that a user can enter the
name of the file to be sorted or reduce the
working areas if space is limited. A
further article will show how data can be
sorted internally using a linked list.
Silly Basic
WE FOUND this stuck:in a cracker left over
from an April 1 party which never
happened. Take an aspirin before en-
tering:
Teensy Basic for MK14
1116 BCD Arithmetic tt
{t Variety of Diagnostics "
!! Fully protected System - if
requires logon password
Yes! All usual Basic functions and more packed into in amazing
40 bytes!
How to use Teensy Basic:
{i) Enter the following program into memory.
OFI2 C4 GE 37 C4 & 33: C4 OF % C4 1 32 OF
OFIF 90 00 C4 42 32 3F Ww 00 % F2 A900 9C
OF2C 06 BAFB % G0 00 6E SE 77 % S50 00 00
OF39 OS 00 00 SO 69 GO OO GS 00 00 OO 50 SC
OFS6 SO SO 79 00 00 O 00 & 42 7) OF FF
(ii) Run the program from OF 12.
You ure now set to enter your first Basic program.
The dispiay will now show ‘Ready’.
To fog on to the system, press any key for exactly 23.58829 ms. This
prevents any unauthorised person using your Basic programs.
If you should press a key accidentally for, say, 23.58828ms, the
display will show ‘Error’ and you can re-try after pressing ‘GO.
Happy programming. ~
PRACTICALCOMPUTING July 1979
We are North
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for the best sales and
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market
If you need advice on which Microcomputer to buy
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Payroll (up to 200 employees - IR. Payroll £250
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Incomplete records £250
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@ Circle No. 242
123
PRACTICAL COMPUTING July 1979
* 4,000 character page with 1,920 characters
viewable at any one time
* 64/96 character set
* Switchable transmission speeds 75—9,600 bps
(split speeds optional)
* HDX FDX (Model 4002) Block Mode (Model
4004)
* Dual interface —RS232C and 20 ma current loop
Introducing the Lyme 4000 family of
visual display computer terminals, the
British-designed and built Terminal
exploiting all the very latest
Microprocessor and N-MOS circuits.
Only 32 Chips provide a VDU giving
the highest performance and flexibility
at low cost.
* Protected areas (defined by reduced intensity)
* XY Cursor addressing, 12” diagonal screen
*12 x 7 dot matrix upper and lower case
* Character delete and insert
* Up to 16 dedicated function keys. Printer Port
RS232 optional
* One off end user price £645
Lyme Peripherals Limited, 2 Avenue Court, Farm Avenue, London NW2 2PT.
Tel: 01-4520490.
“Se “S“E
TELETYPE 43
PET INTERFACE
LA 36 DECWRITER Il
TALLY 160cps BI-DIRECTIONAL
KERR MINIFILE 6000:
Mini-floppy RS232 interface for use as Disc file system. Call us for your cables,
connectors, adaptors, chips, and ROM$ etc.
@ Circle No. 243
BB DATA DESIGN TECHNIQUES LTD
£850
£180
£875
£1650
£875
Our own countrywide maintenance organisation will be pleased to quote for
12 LEEMING ROAD,
BOREHAMWOOD,
HERTS, WD6 4DU.
01-207 1717
KINGS NORTON,
021 459 5959
comprehensive agreements or ad-hoc service to suit your needs.
58-60 NORTHFIELD ROAD,
BIRMINGHAM B30 1JH.
5-6 LOWER CHURCH STREET, GLASGOW:
CHEPSTOW, 041-221 9761
GWENT NP6 5HJ. TELEX:
02912 2193 49280
@ Circle No. 244
. PRACTICALCOMPUTING July 1979
SSeS Sem ys) |e
THE BUYER’S GUIDE is a summary of low-cost computers available in this country. It appears each month; we add new computers and
amend existing information as required to keep up-to-date. The cut-off point is taken as £5,000, because we feel that computer
systems costing more than that for a minimum configuration cannot be summarised adequately in a brief table. Systems are listed
by manufacturer.
If a computer has been reviewed by Practical Computing, the date of the appropriate issue is indicated.
a ay
MANUFACTURER
ACORN COMPUTERS
HARDWARE/SOFTWARE & APPLICATIONS/AVAILABILITY
Acorn. Singie Eurocard-sized microcomputer with 6502 processor, IKB RAM, 16-way !/O.
Max size: a second Eurocard adds hex keypad and CUTS cassette interface. Monitor and
machine-code programming now, Basic and disc operating system in the future. “Highly cost-effective basis for a
computer or an industrial development system”. Sold by post or from Microdigital (051-236 0707).
APPLE COMPUTERS
Apple ll. Min size: 16K memory; 8K ROM; keyboard; monitors; mini assembler; colour
graphics; Pal card; RF modulator; games; paddies and speakers; 4 demo cassettes. Max
size: Expandable to 48K memory; floppy discs and printers are now available. Two versions of Basic, PASCAL;
Assembler; games; business packages. An American system regarded as suitable for any kind of applications.
Maintenance contracts offered. Personal Computers Ltd (01-283 3391) is the sole U.K. agent but has a distributor network
of 20 dealers. (Reviewed July, 1978.)
ATTACHE
Attache. Min size: system with 10 slots, $100 bus, 8080 processor and 16KB housed in
desk-top case with built-in keyboard. Max size: 64KB, parallel printer interface, two
singie- or double-density 8in. floppies, video screen. Disc Basic; business applications produced by Moncoland, the sole
U.K. agent. Distributors include Keen, GBH, Alba, and Lion. ;
.
PRICE
£70.20 inc VAT and
postage for kit. £81
complete for
assembled Acorn.
Around £1,000
From £1,737 without
video or external
storage. Full
business system
with screen, discs
and printer about
£5,000
BRUTECH BEM-CPUI: Single-board processor with 6502 and no RAM. No applications software. From £116
ELECTRONICS Available from Data Precision Equipment (04862 67420). (Reviewed March, 1979.)
COMART ' Microbox. Chassis with three to six PCB sockets for $100 boards, plus fan, Several $100
boards available. Aimed mainly at OEM industrial users and perhaps the serious £255 for full package
. hobbyist. it will take Cromemco, North Star and other processors. Available from Comart plus case
(0480 215005).
COMMODORE Pet. Single unit containing screen, tape cassette and keyboard. Floppy disc, printer and £460-£795 exc VAT
SYSTEMS DIVISION full-size keyboard are options, as are externa! cassettes. Basic; games; business
packages. The British subsidiary of Commodore Systems of the U.S. sells Pet for home,
educationa/ and small business applications. About 80 distributors.
KIM !, processor (6502 chip); small calculator-type keyboard; LED six-digit display; built-in interfaces for audio-cassette £99.96
and Teletype; IK RAM; 2K ROM (can add up to 64K). No software available, but it has three good manuals. An American
import which gives Pet-type capabilities with a maximum configuration. For the hobbyist but used mainly as an
evaluation board for the 6502 chip. Twelve to 15 dealers. (Reviewed October, 1978.)
COMPELEC Series |. 2-80 processor 512MB floppy, 32KB, Centronics printer, VDU. Upto 4MB disc and _—_Less than £5,000 for
ELECTRONICS 64KB. CP/M, Basic, Cobol, PASCAL, Fortran V, Assembler, Business and word processing _ basic system
packages available. From Compelec (01-580 6296), which is also sole supplier of Altair
systems.
COMPUCOLOR Compucolor ll. Packaged system including 13in. eight-colour display with alphanumerics From £1,390
and graphics, 72-key detachable keyboard, 8KB, and built-in mini-floppy. Max size: 32KB.
Extended disc Basic in ROM, graphics programs and games. The system now ranks fourth behind Pet, TRS-80 and Apple
in personal computer sales. Abacus (01-580 8841) is sole U.K. agent and is arranging distributors, including the Byte -
Shop and Transam. (Reviewed June, 1979.)
COMPUCORP 610: desk-top unit using Z-80 and incorporating screen, 150KB floppy, 48KB. Up to 60KB From £3,890
memory, four floppies, printers. Basic, Assembler, DOS, text editor, file manager;
business packages. Nine dealers.
COMPUTER CENTRE Mini kit: Z-80 CPU, CTC, USART, serial and parallel I/O. 16 bytes memory, Western Digital Mini kit: £786.
dise controller, SA400 5in. drive plus CP/M, cables and connectors.
Maxi kit: As above but with DRI 7100 8in. drive instead of Sin. drive. All (33) volumes of CP/M user group library available Maxi kit: £886.
for cost of media. Library includes utilities, games. Basic compilers/interpreters and Algol compiter. Microsoft Basic,
Cobol, Fortran also available. Computer Centre (02514 29607).
COMPUTER System I. Typical size: 40K memory; dual 8in. floppy discs, total storage capacity 1.2MB; System 1, £5,000
WORKSHOP Ricoh daisywheel printer. System 2. Typical size: 24K memory; dual minifloppy dises of plus, System 2, :
80K bytes each; Centronics 779 dot matrix printer; VDU. around £3,000. i
System 3. 12K memory, cassette interface; 40-column dot matrix printer. Editors, Assemblers, Basic, games, information System 3, from \
retrieval package. The systems were designed and built in Peterborough and are suitable for educational and smalt £1,350 |
business users and perhaps the more serious hobbyist. Twenty-five dealers.
CROMEMCO Single-card computer. 4MHz Z-80 CPU, $100 bus, 1KB RAM, sockets for 8K ROM. 20mA/ £247-£281
RS232 serial interface and parallel bi-directional interface. Basic in ROM and Z-80
monitor, For OEM and industrial users; used with backplane for ‘full computer capability’. Comart is the sole agent and
has 12 distributors. (Reviewed February, 1979.)
PRACTICAL COMPUTING July 1979
(continued on page 127)
Ce
125
126
Expand your Pet to its full capability with
these professional peripherals
Dual floppy disk unit
A COMMERCIAL GRADE DISK SYSTEM FOR
THE PET
@ Upto 800K Bytes on Line Mass Storage
@ High Speed D.O.S. in ROM
@ Effectively doubles PET operating system
commands —
@ Complete documentation allows use of full
resources :
@ Handles upto four disk drives
@ Includes Commercial Printer Support
@ Adds 16 commands to PET basic
@ Automatic self reorganisation of free space
on disk after each save or erase command
@ Free space is never fragmented
PRICE £840-00
Expandem memory expansion board
General purpose expansion system for PET and
other 6502 Computer Systems (e.g. KIM, SIM,
AIM).
@ 24K to 32K Low Dissipation RAM.
@ Mounting slots for 4 option cards
@ All necessary cables and brackets
@ Disk Controller
@ Parallel 1/0
@ Sockets for Eprom
@ Flexible Serial 1/0
@ $100 1/0 Driver
24K Board £320-00
All Apple tl and Exidy Sorcerer ranges stocked.
24K £449-00
PET 2001-4 4K Bytes of Memory
PET 2001-8 8K Bytes of Memory
PET 2001-32N 32 Bytes Memory £795-00
PET 2ND Cassette Unit £5500
PET Sound Box Plugs direct into 2nd Cassette
Port complete with Demo Software £12-98
£460-00
£550-00
PET Dust Covers To protect your PET—(Four
Colours) Rust, Blue, Beige, Green £8-33
PET TV Interface Plugs direct into user port
Superb Specification £45-29
Unidirectional [EEE to RS232 interface £85°00
Bi-directional IEEE to RS232intertace £160°00
Cifer Cub visual display terminals with keybcard
£380-00
£3-98 per 10
£27-78 per 10
C12 blank data cassettes
5 in. Mini-floppy diskettes
All new equipment sold by us carries a 12 months’ guarantee
HB COMPUTERS LID
Business
Computers for
Home
Software
Estate Agency: Very cheap, very effective
method of showing properties to customers.
Automatic deletion. Printed copies for prospec-
tive purchasers (Now available on disk). £25-00
Mail List: Printout all your mailshots, names and
addresses; printout on self-adhesive labels;
disk only £15-00
Payroll: Complete suite, abundant storage on
disk. End-of-year summary; coin analysis; two
payslips; excellent value; disk only £50-00
R.H. MICROPOLY: Monopoly on an 8K Pet,
would you believe? Absolutely superb.
R.H. Mastermind: Surely the best Mastermind
ever. 3 Games levels. £5-00
R.H. Shape Matching: Match up two different
shapes to score. You against the other guy. You
will have to be sharp for this one. £5-00
We supply all Commodore, Petsoft and
Compusette programs. We should be glad to
quote for dedicated software applications.
Access and Barclaycard accepted for Telephone
and Postal Orders.
All prices include post and packing (insured
post extra}.
Dealer enquiries invited for ail our stock items.
U.K.-wide service by our specialist technical
staff. Maintenance contracts available after our
One-year guarantee at 7$% of capital purchase
Price.
All prices exclusive of VAT
22 Newland Street
Kettering Northants
Telephone (0536) 83922/
520910 Telex 341297
@ Circle No. 245
THE SGS-ATES NANOCOMPUTER,
Probably the best microcomputer system for education in
the world,
will be displayed for the first time, in the UK, on stand 16
at the 1979 Microcomputer Show.
SGS-ATES Nanocomputers are distributed by:
THE MIDWICH COMPUTER COMPANY LTD.
HILLSBOROUGH HOUSE,
CHURCHGATE STREET,
OLD HARLOW,
ESSEX.
@ Circle No. 246
PRACTICAL COMPUTING July 1979
eee lS’ Culdc—
(continued from page 125)
MANUFACTURER HARDWARE/SOFTWARE & APPLICATIONS/AVAILABILITY
PRICE
CROMEMCO continued
2-2. Min size: chassis, 30A power supply, motherboard, Z-80 processor, 16KB memory. Max size: 512KB, 21 sockets,
three minifloppies or four 8in. floppies. Basic, Fortran, Cobol, assemblers. For serious hobbyists, OEMs, educational
applications, and industrial/scientific users.
System Two. Min size: factory-assembled system with 32KB, dual 90K minifloppies, dua! printer interface, serial
interface. Max size: two additional floppies, 512KB, up to seven terminals. CP/M-compatibie operating system (DCOS),
Fortran, Cobol, Basic, assemblers, word processing, database manager. Multi-user system for software development, or
scientific/industrial/business users.
System Two/64. New configuration featuring mini-diskette drives and 64K bytes memory. Software and application as
System Two.
System Three. Min size: 32KB, dual 256KB floppies, dual printer Interface, 20mA/RS232 serial interface, Z-80 processor.
Max size: two additional discs, 12KB, seven terminals, multi-channel A/D and D/A interface, PROM programmer.
Software as for System Two. Described as appropriate for smail to medium business, scientific and industrial
users—“‘rivals minicomputers at more than twice the price”.
System Three/64. New configuration featuring dual 8in. diskette drives; Z-80A processor; 64K of 4MHz memory;
console and printer interfaces. Macro Assembler, Fortran iV, Extended Basic, Cobol, Multi-user Basic.
EQUINOX
Equinox 300. Min size: 48K memory; dual floppy discs giving 600K bytes of storage;
16-bit Western Digitai m.p.u. Max size: up to 256K memory; up to four 10MB hard discs.
Basic, Lisp, PASCAL, Macro Assembler, Text Processor. All software bundled. The system is a multi-user, multi-tasking,
time-sharing system for two to 12 users. Application software available for general commercial users. Sole distributors
Equinox Computers Ltd (01-739 2387}.
EXIDY
Sorcerer: based on Z-80. 16K and 32K; cartridge and cassette interfaces; 79-key
keyboard; 256-character set (128 graphics symbols), 12in. video monitor; expandable
with Micropolis floppy discs. Basic, Assembler and Editor; games, word processor. Other pre-packaged programs plus
EPROM pack for your own programs on cartridges. There is no sole importer for U.K.; sold through various importers
and dealers. (Reviewed March, 1979.) ; ;
HEWART
MICROELECTRONICS
Mini 6800 Mk Hl. IK monitor; IK user RAM, IK VDU RAM; CUTS. Upper-and lower-case
VDU with graphics option. 128-byte scratchpad; decoder/buffer; power supply Basic in
ROM; monitor command summary, SWTPC programs; Newbear 6800; Scetbi 6800
Cookbook. Markets are small business, education and home user. Cash with order to Hewart. (0625) 22030.
£372 {in kit form) to
more than £4,000
£2,294 upwards
£3,050
£3,444 to more than
£10,000
£4,385
£5,000-£40,000
plus.
£760 for 16K, £859
for 32K (excludes
video monitor);
£1,200 with floppy
discs.
From £127-50 plus
VAT
6800S. 16K dynamic RAM; IK Mikbug-compatible monitor; room for 8K Basic in ROM; upper-and lower-case graphics; From £275 plus
single floppy disc drive; printer and high-speed tape interfaces. “Mountains of software available’. Test tape with CUTS VAT.
test tones, test message and games with kit.
DIGITAL DSC-2, Min size: 32KB, but 64K standard; 2-80; over IMB floppy disc on two single-sided From £4,465.
MICROSYSTEMS 8in. drives; four programmable RS232 and one parallel interface. CP/M and Basic
‘ included in price. Extended Basic, Fortran, Cobol, text processing, Macro Assembler, Link
Loader, business packages and CAP-CPP business software. Add-on rigid disc system (14 and 28MB} availabie soon.
Modata (0892 39591) is sole U.K. distributor; dealers being appointed.
IMSAI VDP 40: 32K or 64K RAM memory Qin. display screen, standard keyboard. Two Siin. £4,507 for 32K
floppy disc drives; serial |/O. No software support, but packages for the larger VDP-80 model.
could be converted for smaller system. This would be from about £700 per package. Computer Mart, Norwich (0603
615089), is the main U.K. supplier but there are other distributors.
ITT 2020. identical to Apple ll. Min. size: 4K memory; 8K ROM; keyboard, monitor, colour From £827 for 4K
graphics, mini assembier; Powell card; RF modulator, games, paddies and speaker; Max and cassette, to
size: 48K with floppy dises and printers. Basic, Assembler, games, business packages. Generally suited to any type of £1,114 for 32K plus
application. Fifteen wholesalers, including Fairhurst Instruments. floppy and printer.
£3,003 for 48K
version, two
Micros. Typical size: iK monitor; 47-key solid state keyboard; interfaces for video,
cassette, printer and UHF TV; serial {/O, dual parallel 1/O ports; 2K RAM; power supply.
2K Basic; British-designed and manufactured system. Claimed to be the cheapest data terminat~— a system with an
acoustic coupler and VDU for £1,020. Prospective applications for small businesses, process controllers and hobbyists.
Manufacturer is sole distributor (01-892 7044).
MICRONICS
floppies and serial
printer.
From £400,
assembied.
MICRO V Microstar. Single box with twin 8in. floppy discs, 64K RAM, three RS232 serial inputs,
STARDOS operating system enables system to have three VDUs, plus a fourth job
running simultaneously. Word processing software available. Packages being developed include invoicing system,
payroll, accountancy type system. Price includes a reporter generator language. Imported by a Data Efficiency
subsidiary, Microsense Computers, Microsolve is London agent; other distributors being arranged.
MIDWEST MSI 6800. Min size: 16K memory Act! terminal: cassette interface. Max size: three disc
SCIENTIFIC systems — minifioppy system with triple drives of 80 bytes each and 32K memory, large
INSTRUMENTS floppy system with up to four 312K-byte discs and 56K of memory mounted ina pedestal
desk, or hard disc system with 10MB and 56K. Basic interpreter and compiler; editor;
assembler; text processor on small disc system. American-designed system being manufactured increasingly in the U.K.
Sole U.K. agent is Strumech (SEED} (05433 4321) but a distributor network is being established.
Nascom I. Min size: CPU; 2K memory; parallel 1/0; seria] data interface; |K monitor in
EPROM. Max size: CPU; 64K memory; up to 16 parallel I/O ports. Mostly games, but also
a dedicated text editor system written by ICL Dataskil. Nascom is working on large
versions of Basic, and 8K Microsoft Basic should be available soon. Eleven distributors in U.K. Nascom is negotiating to
increase the number. (Reviewed January, 1979.)
—— ae a oe
NASCOM
MICROCOMPUTERS
esate
PRACTICAL COMPUTING July 1979
£4,950 or machine
and software.
Basic system:
£1,100 (£815 as kit);
Minidisc, £2,500;
Large floppy disc
£3,200, plus £1,400
for quad system;
hard disc,
£8,000-£12,000.
£165 exc. VAT.
(continued on page 129)
q
127
ROBOX LTD
—_— FOR PET IN SCOTLAND
We stock the famous
=f, PETSOFT SOFTWARE SUPERMARKET
a. * ALL THIS AND MORE FROM ROBOX *
Peripherals, field service and software consultancy
service available
We supply ex-stock the ANADEX DP8000
Sass
ROBOX, Scottish Agents for Kingston Computers
Interfaces
Floppy discs
Memory expansion
Bus connectors
ROBOX, Agents for CBM, Texas, Hewlett Packard
and Casio range of calculators
Full range in stock
ALL THIS FROM ROBOX.COME AND SEE US. KIRKINTILLOCH: 84 TOWNHEAD 041-776 4388/1253
ROBOX LTD 2222s
@ Circle No. 247
ZYTEL «.. DYNABYTE
THE NEWEST, MOST EXCITING SYSTEM YET TO COME FROM THE USA
See advertisement on page 72 for full details
ATTENTION ALL 6800/SS50 BUS SYSTEM USERS (eg SWTPC)
You can now run the FASTER, MORE
POWERFUL Z80 CPU on your system using Z80
CPU board.
Will it cost a fortune???
NO ONLY £150.00 + VAT (8%).
Plugs directly into your SS50 bus system (co-
resident with your 6800 CPU if you wish).
Supplied with 2K monitor plus socketed space for
extra 14K of EPROM on board.
Enables you to run a wide range of Z80-based
software.
12K extended basic available on EPROM.
| VIDEO OUTPUT BOARD for SWTPC. Plugs
directly into I/O section of motherboard and
coupled to a MPL parallel interface gives
DIRECT VIDEO in 16x64 format.
ONLY £68.00 + VAT (8%).
Uses the Thompson-CSF SFF96364 CRT con-
troller microprocessor.
2 X 2114 static memory chips.
A 2513 character generator chip. Cursor control
decoder prom
Full scrolling capabilities.
For further details of DYNABYTE or our range of SSSO Bus compatible products contact
ZYTEL. at:
MICROWAVE MODULES LTD., P.M. ELECTRONIC SERVICES,
BROOKFIELD DRIVE, 2, ALEXANDER DRIVE, HESWALL,
AINTREE, LIVERPOOL, L9 7AN. or WIRRAL, MERSEYSIDE, L61 6XT.
Tel: 051-342 4011 Telex: 628608 Tel: 051-342 4443 Telex: 627371
Contact: Richard Butterfiéld Contact: Bruce Norcliffe
@ Circle No. 248
128 PRACTICAL COMPUTING July 1979
EE See (we! 2) (||
(continued from page 127)
MANUFACTURER HARDWARE/ SOFTWARE & APPLICATIONS/AVAILABILITY PRICE
NATIONAL Pegasus. Min size: 48K; Z-80; double-density floppies (320KB); $100 bus; 12in. CRT; 58- £2,700 exc. VAT.
MULTIPLEX key keyboard; two serial and one parallel interfaces; bi-directional printer. Options: 8in.
drives; 1-2MB additional drives; digital recorder 9,600 baud. Assembler, Cobol, Fortran,
Extended Basic. General business package available as well as text editing and mailing list. All run under CP/M. Suitable
for education, business and home users. London Computer Store (01-388 5721) sole supplier.
NETRONICS Elf 11; single-board computer in kit form or assembled, RCA Cosmac 1802 processor, hex Basic kit £115°50 inc
keyboard, 256 bytes RAM; options include up to 64KB, ASCII keyboard, cassette and VAT, p&p, power
RS232 1/0, and video output. Machine code or Tiny Basic. Promoted as a teaching system in minimal form, but supply. Assembled
expandabie for more general use. Sole U.K. distributor HL Audio (01-739 1582). plus user manuals,
£164-10. 1/O board
adds £40-95; Basic is
£14-95.
NEWBEAR 7768. CPU board, 4K memory, cassette and VDU interfaces. Range of Basics and games, From £45,
British-manufactured system for hobbyists. Expandable to 64K memory, available only in
kit form. From Newbear; also from Bearbag dealers, Microdigital, Microbits.
NORTH STAR Horizon. Min size: 16K memory; Z-80A processor, single minifloppy disc drive (180KB). £995 to £2,500.
Max size: 56K memory, four minifloppy disc drives (180KB), any acceptable $100
peripheral boards, Basic (includes random and sequential access), disc operating system and monitor. Options: Basic
Compiler, Fortran, Cobol, Pilot, PASCAL and ISAM. The system is suitable for commercial, education and scientific
applications. Application software for general commercial users. Twenty distributors. (Reviewed April, 1979.)
OHIO SCIENTIFIC Ohio Superboard II: Min size: 6502 processor, 8K Basic in ROM; 2K monitor in ROM; From £298,
4K RAM; Cassette I/F. full keyboard; 32 x 32 video I/F, 8K Basic in ROM; Assembier/ .
Editor; American single-board system with in-board keyboard. Aimed at hobbyist/smali business. Ohio makes games,
personal maths tutors, and business programs. This and other Ohio products have six U.K. distributors. (Reviewed June,
1979.)
Chalienger C24P: similar to Superboard but with a 32 x 64 character set. Supplied as two separate boards with open £620 to £1,595.
slots for expansion. The ‘professional portable’; similar to Superboard but packaged and ready to use. Aimed at small
business, education, research.
Challenger C26P: simitar to 4P but expandable to include two Bin. floppies, allowing use of Ohio software. Personal £825-£2,670.
computerfor larger business/commercial programs. Aimed at smal! business, education and research.
Chaltenger C3, Min size: 32K RAM, dual 8in, floppies, triple processor architecture (6502A, Z-80, 6800). Max size: 768K £3,425-£13,000.
RAM, 74MB hard disc, multipte terminals, printers. Can run virtually all 6502, 6800, 8080 and Z-80 code. Runs Basic,
Cobol and Fortran under OS CP/M. Full business software packages available, including word processing and database
management. Multi-programming available.
PERTEC System 1300, Min size: 32K memory; dual minifloppy discs 71 bytes each, formatted; £3,000-£5,500. |
serial interfaces. Max size: 64K memory; four serial ports. Basic (single and multi-user), i
Fortran, Cobol. The hardware for Compelec Altair systems is from Pertec but the software is Anglo-Dutch. Sole |
distributor Compelec (01-580 6296). |
PROCESSOR Sol. 808-based $100 microcomputer packaged with cassette and video interfaces From £1,750 |
TECHNOLOGY (including graphics), keyboard with numeric pad, and 16KB RAM. Basic, assembler, word (excluding monitor |
processors. Floppy disc systems available. Several distributors including Comart (0480 and cassette).
215005), which can offer nationwide maintenance contracts. (Reviewed, July, 1979.) Complete floppy
disc systems with
word processing
about £5,000. |
RAIR Black Box. Min size: 32K memory dual minifloppy discs, 80K bytes each; two From £2,300.
programmable serial i/O interfaces, Max size: 64K memory; eight serial interfaces; IMB {
disc storage (or 10MB hard disc); range of peripherals. Basic, Fortran !V; Cobol. Hardware distributors are being signed |
and agreements made with software houses to add software. A warranty and U.K.-wide on-site maintenance is given. |
From manufacturer (01-836 4663) and systems houses.
RESEARCH 380-Z. Min size: 4K memory; 380-Z processor, keyboard. Max size: 56K memory.
MACHINES LTD Options: cassette, single or dual minifloppy discs, dual 8in. double-sided discs ({MB); From £830-£3,500.
serial interfaces; parallel interfaces; analogue interface; printer available, Basic
interpreter, Z-80 Assembler; interactive text editor: terminal mode software; data logging routines; CP/M, DOS, text
processor, C Basic, Fortran, Algol, Pilot, Cobol, CP/M users’ club tibrary. Sold principally to higher and secondary
education, and for scientific research, data processing and data logging. Available from Sintel and the manufacturer.
(Reviewed December, 1978.)
280-Z. Board version of 380-Z system. 4K or 32K (identical in performance to the 380-2). Interfaces, software as for 4KB version at £398;
380-Z. 32KB for £722.
RCA Elf 1: RCA 1802 micro with hex keypad and output to TV screen. Assembler and machine From £99:85 in kit
code programming; options include Tiny Basic. Avallable by mall order from HL Audio form; £164-10
{01-739 1582). including postage
5 and VAT.
ROCKWELL - Aim-65: Kim-compatible with full keyboard and on-board printer. IK or 4K RAM. The 4K IK ~ £249-50.
version is described as a development system rather than a personal computer. 4K — £315.
Assembler, editor. Basic. Available from Pelco and Microdigital. (Raviewed July, 1979.)
SCIENCE OF MK14: SC/MP processor, 256 bytes user memory; 512-byte PROM with monitor £39-95 basic.
CAMBRIDGE program; hex keyboard and eight-digit, seven-segment display; interface circuitry; 5V
regulator on board. To this can be added: 3K RAM (£3-60); 16 I/O chip (£7:80); cassette
interface kit (£5-95); cassette interface and replacement monitor (£7-95); PROM programmer (£9-95). No software
provided but a 100-page manual includes a number which will fit into 256 bytes covering monitors, maths, electronics
systems, music and miscellaneous. Based on American Nationa! Semiconductor chips. Science will soon have a VDU
interface and large manuai on user programming. Mail order from manufacturer (0223 312919) and by selected dealers.
(Reviewed May, 1979.) (continued on next page) +
' . a 1
PRACTICAL COMPUTING July 1979 129
LIers 6, aaa a a nS ee
(continued from previous page)
‘MANUFACTURER HARDWARE/SOFTWARE & APPLICATIONS/AVAILABILITY PRICE |
SDS SDS 100, Sing!e unit containing 32K memory (expandable to 64K); up to 8K PROM; twin From £3,750 (basic
double-sided floppy disc drives of 500 bytes each, serial and parallel RS$232 interfacing; machine) pius £890 |
keyboard; 12in. video display; power supplies; SD monitor program; line printer available. CP/M, 8080 (printer); £4,500
assembler, E Basic, Editor supplied with system; M Basic, Fortran, Cobol available for business use, industrial process combined. |
monitoring and control (with additional hardware). All CP/M games and business packages. Sole supplier Airamco (0294
65530). |
SORD M100. Min. size: 16K RAM; 4K ROM monitor; full keyboard plus function keypad; two- From £726
channel joystick dual cassette I/F; liK EBasic on cassette; video; graphics; printer; $100
bus; converters; speaker; 24-hour clock. Max size; 48K RAM; 8K ROM; black and white or colour graphics; mini-floppy
discs. Suitable for OEMs, small business, education, laboratory and scientific and home computing. Main distributor is
Dectrade, but for London and South contact Midas Computer Services (0903) 814523.
M222. Min size: 64K RAM; VDU; full keyboard; numeric keypad; graphics; real-time clock; 70K minifloppy disc drive; From £3,450-£4,123 |
audio cassette interface; two serial ports; programmable 110 to 9,600 baud; three $100 slots; power and interface for includingdeskand
two external minifloppy drives; ROM bootstrap. Max size: 70K byte minifloppies; black and white or colour graphics; bar _ printer.
code reader; TMS-1000 development system. EBasic interpreter; compiler EBasic; matrix Basic; Fortran; Cobol; {
assembler editor; re-locatable linker/loader; debugger. Application software includes word and graphics processor; |
business demonstration packages and games. For small business; industrial/research, education; software houses
OEMs. |
M223. Min size: 64K RAM; hardware as M222 plus one or two 350K byte minifioppy drives. Max size: Four 350K From £3,775-£4,448
minifloppies; up to four 11.4Mb hard discs; range of S100 devices, As M222 plus Cobol-80, CAP-CPP BOS MicroCobol. |
Application software includes word and graphics processor; personal information processing system; games; CAP-CPP
range of MicroCobol software. .
SYNERTEK Sym t: 6502 chip and keypad with memory available in 4K biocks to 64K. Any Kim From £200
software. American, meant to be the foundation system for very small business and
hobbyist users. Available from Newbear (0635 49223).
TANDY CORP. TRS-80. Min size: Level | 4K memory; video monitor; cassette; power supply. Max size: Level i-£499
| Level if 48K up to 350K on-line via floppy discs; line printer; tractor feed printer and quick Level li-from
printer; floppy disc system. Modem, telephone interface soon available. Basic; some business packages. Leveilaimedat £578~-£4,700
the hobbyist and education market and Level tl at sma!l business applications. Hundreds of dealers. (Reviewed
November, 1978.)
| TRANSAM Triton: British-made kit computer. Up to 65KB. Full graphics capability, 64 characters. £286 kit with 5KB. ]
COMPONENTS Power supply; cabinet. Communications interfaces. Tiny Basic or 2K Basic, KB monitar
plus new option 4K firmware on board. Available from manufacturer. {01-402 8137).
VECTOR GRAPHIC 48KB RAM, 2-80 micro: 63K bytes, mini-discs are standard, Options: graphics. Monitor, £2,300
MDOS, Basic; business packages from dealers. Several distributors.
DYLE HOUSE) Present
TRS-80 Special
Dual density double sided 8" discs (over 2 megabytes of on-line storage)
Dyle House Business Basic & Disc Operating System.
Fast maths with the MM 57109 number cruncher.
Plus a very special option.
“Multi Cluster Intelligent Disc Controller”
As many TRS 80 units as you wish linked into a single communications network.
Free Business Software
Accountancy — Payroll — Stock Contro] — Manufacturing.
Fully Integrated Sales Contro] — Invoice & Purchase Orders.
System prices starting at £4000 (including 140 c.p’s full width printer.)
DYLE HOUSE LIMITED, Brook Crescent, London E.4 01-529-2436/1760
@ Circle No. 249
130 PRACTICAL COMPUTING July 1979
TE eee
A PRACTICAL |
GLOSSARY
Continuing the terminological gamut from I to M
Interface
A word much-loved by the
jargon writers, an interface is
the boundary between two sys-
tems, and within that can be
practically anything from an
airy cOncept to a piece of very
solid hardware.
On the one hand it is possible,
and even sometimes heipful, to |
think of the man-machine inter-
face as residing somewhere in
the brain of the human, who
perceives what is happening
and who decides to interact
with the machines.
On the other hand, it is gener-
ally more useful to think of an
interface as a plug, a socket, or
a cable; or alt three. The inter-
face between a cassette player
and a microcomputer is the
connection between them, the
connection which passes infor-
mation or data from one to the
other.
Programs can have _inter-
faces, too, which is where the
‘logical’ bit comes in;
they
aren't solid, physical interfaces, |
but those parts of a program |
which can pass information or
data to other programs. And so
on.
The crucial aspect of inter-
faces is that they should be
well-defined, wherever or what-
ever they are; so that both sides
of the connection should know
what to expect, and so that
information can be passed
satisfactorily from one to the
other.
Take the CCITT V24 standard, |
also known as the EIA RS232-C |
specification. This is a well-
accepted standard for connect- |
ing things physically; it defines
which wires go to which pins in
a plug-and-socket connection,
and effectively it defines the
shapes of the plug.
It is widely used and most
terminals and printers offer a
V24 connection; even so, there
is plenty of room for variety and
many terminals require you to
juggle the wires around before
the plug is satisfactorily into the
socket.
IS
Conventional abbreviation for
index sequential (qv).
Label
Like the literal descriptive defin-
| Pathan
ition, it’s a descriptive identifier.
Typically a label is a group of
characters used to identify a
file, a message, or a. record;
very specifically, the term also
denotes an instruction in a
program.
Some programming tan-
guages allow you to reference a
label rather than an absolute
address or a particular line
number; so instead of a branch
instruction like GOTO 40, where
40 is a line number, you might
be allowed to say GOTO SUB-
ROUTINE ’B”’.
Language
This one’s tricky. Between them
Wittgenstein and Chomsky had
some difficulty composing a
simple definition. Still, it’s obvi-
ous that the essential element is
communication; and in com-
puting, a programming ftan-
guage is a code — or a defined
set of symbols or a notation ora
systematic means Of communi-
cation — whereby humans can
communicate with computers.
The analogy with human lan-
guages is very good. There is
no point in using Swahili to a
if the {Indian doesn’t
know the language. Speaking in
Swahili to someone who knows
that language is a good way to
impart information. In fact, the
only simple way for two people
| to pass information is by agree-
ing, probably implicity, on
what a set of written squiggles
or spoken grunts means.
So it is with computers. Basic
and Cobot and the rest are
alternative ways of expressing
information; if you and the
computer both ‘know’ one of
them, you can write a program
which will run on that com-
puter.
With a definition like this, it
should be said that languages
are in several varieties. There
are three — machine code, as-
semblers, and high-level fan-
guages. All are being defined as
we go, but briefly machine code
relates directly to how the com-
puter processes instructions, so
normally it consists of a binary
code, a string of Os and 1s
which will be meaningless to
anyone who doesn’t know this
| is a code the computer can
| understand.
Assembler is one step up,
coding the binary instructions
into more or less meaningful
PRACTICAL COMPUTING July 1979
alphanumeric symbols but it’s
still related directly to the way a
particular computer operates.
High-level languages are dis-
tanced one step further from
the insides of the processor; the
instructions usually bear some
resemblance to English but,
more important, the high-level
language can, in theory, run on
more than one computer. In
practice, for each computer
there’s a different transiator
which converts the high-level
language into machine code.
Latency
It is just possible you might
meet this word. It refers to a
delay or a waiting state in the
middte of some operation. You
might encounter it among the
fine print of a floppy disc
manual — it’s the delay while the
read/write head is moving, plus
the time the disc takes to. rotate
to the required data position. In
other words, nothing happens
during fatency, but something
is about to happen.
LCD
Liquid crystal display. Some
crystals are liquid, and some
liquid crystats light if you tickle
them with a burst of electricity.
LCDs are used in pocket cal-
culators and digital watches,
normally as an alternative to
LED displays. The technology
probably isn’t a serious conten-
der when a great deal of infor-
mation has to be displayed
quickly; you can’t beat the
cathode ray tube for that.
Leased line
If you want to link your compu-
ter to another, there are realisti-
cally two ways of doing it - a
cheap way and an expensive
way. The cheap way is via the
ordinary dialled telephone
system. You'll need a modem
or an acoustic coupler but you'll
pay only the normal dial rates.
You will be competing with
crossed lines and other interfer-
ence, though, so if you know
where the recipient of your
transmission is, and if youneed
a high-quality transmission
signal, and if you have the extra
money, you might lease your
own private telephone iine to
do the job. You will still need
|! modems — more of that later.
LED
Light-emitting diode. Most digi-
tal read-outs on laboratory in-
struments, calculators and
watches use LED display. A
diode is a simple electron tube |
which lights when you pass |
electricity through it, so where
you need a simple display —
exactly what they are — LED}
displays are the natural choice. |
Liebniz
Gottfried Wilhelm von Leibniz
was One of those 17th-century
polymaths you usually see
wearing an unlikely curly wig
and looking coolly benign. Leib-
niz was reportedly a cheery soul
who dabbled with faw, logic,
religion, politics, diplomacy,
philosophy, history, librarian-
ship, inventions and maths. He |
has a place here because,
around 1694, he invented a
mechanically unreliable and
economically unmarketable cal-
culator. Pascal had already built
One to add and subtract; the
Leibniz version could multiply
and divide, too. Since it didn't
work he moved to other things,
notably letter-writing - there
are at least 15,000 of his letters
around — and philosophy.
Library
A collection of program sub-
routines to insert in programs |
or data files.
Light pen
A photo-electric device which
can detect the presence of light
at a particular point on a CRT
display screen. It looks fike a
pen but it’s connected by cable
to a controfler. You point it at
the place on the screen you |
want to reference; the controller
detects where you are. Depend-
ing on the programming, the
computer could then modify the
display or perhaps accept
something as input data.
Line
It's a connection, usually a
cable, between one part Of the
| system and another — like
| screen and keyboard — or one
computer and another. See fine
speed.
Line feed
| The command which moves the
| paper in a printer up by one
line; on a display screen then
(continued on page 133)
131
e+e et &
ee i
[OW / KEYBOARDS
@ Circle No. 250
132
Professional
ASCII
Keyboards
arr.
8( 8! 8 8 Gi
witey u EIA)
intended for professional micro-processor applications.
This one Keyboard will meet most present and future
requirements.
Full 128-character ASCII 8-bit code.
Tri-mode MOS encoding.
Applications notes for auto repeat, numeric pad,
serial output.
Upper and lower case characters generated by keyboard
with latching shift-fock.
Selectable polarity.
Size 305 x 140 x 32mm. (12% x 5% x T%in)
MOS/DTL/TTL compatible outputs.
New guaranteed OEM grade components.
Needs +5 and —12V supply. ~
Board has space for small low cost DC/DC converter so
that entire unit operates off single 5V rail.
Alpha tock.
Extra loose keys available.
Supplied complete with full technical data.
Rugged mil. spec. G-10 PCB with plated through holes.
2-key roll-over.
DC level and pulse strobe signal for easy interface to any
8-bit input port microprocessor system, video display or
terminal board.
Strobe pulse width 1 ms.
User selection of positive or negative logic data and
strobe output.
eee 8H
*
+e eee
+
Model 756 ASCII Keyboard. Fully assembled
Two or more
Model 756 MF “ Ls od
with metal mounting frame
Edge Connector, gold plated. Type 756/con
Numeric keypad. Type 710
} Plastic enclosure, black. Type 701
] DC to DC converter, for —12VTyps DC512
U.K. orders add 8% VAT on order total.
Generous D.E.M. & distributor discounts available
Stockists required in some areas
CITADEL PRODUCTS LTD.
50 High St., Edgware, Middx. HA8 7EP, England.
V. & T. ELECTRONICS
ASSEMBLER FOR NASCOM ON TAPE £10-00
supports all standard mnemonics, occupies 34K available
in sixteen different versions, i.e. one for each page of
O to F; please state which page you require.
CONVERSION KIT TO PLACE NASCOM
MONITOR & VDU ON ANY PAGE IN MEMORY
please write or phone for details.
THIS MONTH'S SPECIAL OFFER: NATIONAL
MM5270 4KxI 200NS CERAMIC PACKAGE
£10:00 FOR 8
21L02 450ns
21L02 250ns
4116 250ns
2114 300ns
8 off £6:00
8 off £7-00
8 off £7-00
2 off £11-50
Z80 cpu £13-00
Z80 cpu £16-00
Z80 PIO =£15-00
2716 INTEL 1 off £23-50
We apologise to our customers who have tried to contact
us at Dartmouth Rd, N. W2., but we haven't moved
yet—our address is still as below. Stuck for a bit in
the middle of the night? We are often open very late
but please phone first. if you don’t see what you need
in this ad, please phone and enquire. By the time this
ad appears, we hope to have some 8 in. floppies in at silly
prices—first come, first served.
Please add 40p postage then 8% V.A.T.
V&T ELECTRONICS 01-263 2643
82 CHESTER ROAD, LONDON N.19
@ Circle No. 251
We supply Apple and Commodore Pet Computers and
connect them with any peripherals you can think of. (We
will help you to connect even scientific or measuring
devices to the computers).
We keep stocks of Chips, Discs, Books on Basic etc., Fan-
fold listing paper etc.,
€xtra RAM for Apple and Pet at attractive prices. r J
| A standard 1BM Selectric typewriter os
1 a) is the heart of terminals which you
oo can connect to your Apple —
a) from £695.00.
COMPUTER
SYSTEMS
WITH...
Easy to operate
standard accounting
programmes for
under £3,000,or
combined with word
processing machine
for under £4,500
outright purchase or
easy repayment ia
scheme Dedmere Road,
row, Bucks
Tel Martow 2.789
@ Circle No. 252
PRACTICAL COMPUTING July 1979
Oe
(continued from page 131)
effect is to move the cursor on
to the next line.
Line speed
This is about the only time
you'll use the word ‘line’ in the
communications context. Line
speed is the data rate, which
means the maximum rate at
which data can reliably be sent
down a line.
Linear programming
Some programming techniques
are mathematical; they utilise
equations, follow mathematical
logic, and essentially calculate
things. Linear programming is a
branch of this esoterica, much
used in ‘what if’ problems-like
routeing vehicles to optimise
fuel consumption, economic
planning to balance all the vari-
ables, and so on.
Line printer
A line printer is a printer which
prints one line at a time. It
contrasts with a serial printer,
which prints one character at a
time. Line printers are generally
faster and more complicated, so
they tend to be more expensive.
| when you read it in.
LISP
Processing language which be-
longs to the intellectually re-
fined reaches of programming.
List processing is processing
data in the form of lists.
Load |
To transfer something from
memory to backing store, or
vice versa, you load a program
from cassette into the memory
Two other loads are of some
importance. One is the obvious
physical action of placing a
cassette or floppy disc or paper
in the appropriate device. The
other usage refers to internal |
operations of moving around
data — your programming lan-
guage may well allow you to
load specific locations with
specified data, especially if it's
an assembler.
Location
Loosely, it’s a synonym for
address. More precisely, it
means the same as absolute
address, a particular storage
area in memory
Logic
Computers are fast idiot rule-
followers because they are elec-
tronic and logical. In rarefied
terms, fogic is the formal and
systematised interconnection of
discrete components. The em-
phasis in on the interconnection
— logic relates things together —
and on the formal bit — logic
doesn't necessarily have any
relationship to physical matters
like a hardware organisation.
In practice, and in microcom-
puters, logic means the circuitry
which performs logical func-
tions, and since much micro
circuitry does this, the term
‘logic’ is applied loosely to any
t
of its circuitry.
Loop
A loop is a group of instructions
in a program which may be
executed more than once
before the program continues.
The loop includes one instruc-
tion which increments some
kind of counter and another
which checks the counter it
sees if it’s reached a specified
exit total. All this is the same as
iterate (qv).
LSI
‘Large-scale integration. See in-
tegration. All micros use LSI, a
loosely-defined term meaning
electronic circuitry with a large
number of logical operations
per component. ;
LSI-4
A minicomputer from Compu-
ter Automation. It does not have
as much LSI circuitry as the
micros and Computer Automa-
tion doesn’t generally sell them
on a one-off basis. If you can
obtain an LSI-4 it would make
an interesting contrast with the
upmarket micros. ,
LSI-11
The 16-bit micro from Digital!
Equipment, which builds a com-
puter around it (the PDP-11/03).
So do other companies, Plessey
among them. Not many person-
al computers utilise the LSI-11,
so the Heathkit H-11 is an
honourable exception.
Machine
All-purpose jargon word for
processor, computer or system.
Advertisement Index
Acorn Computers
Airamco :
A. J. Harding
Almarc Data Systems
American Data Home and Office
Computers
Anadex
Analog Electronics
Applied Computer Techniques
Belvedere Computer Services
Benchmark Computer Systems.
Betos
Beyts Logic
Business Resources
Byte Shop
Boer De, Electronika
Caddis Computer Systems
Cambridge Computer Store
Camden Electronics
CCS Microhire
CC Soft
Chiltern Microcomputers
Chromasonic Electronics
Citadel Products
Comart
Comp Com puter Components
Compelec Electronics
Computer Field Maintenance
Computastore
Computer Workshop
Computrade
Crofton Electronics
Crystal Electronics
DAMS (Office Equipment)
Data Design Techniques
Digitus
Dillons University Bookshop
Distributed Data Processing
Dyle House
Equinox Computer Systems
Euro-Calc
27 | Factor One Computers 50 | Paxton Computers 40
70,79 Pelco (Electronics) 30
106 | Gemsoft 40 | Personal Computers 85
g | Grama (Winter) 5 | Petalect Electronic Services 112
Petsoft 110
13 | Happy Memories 96 | PM Electronics 128
12 | HB Computers 126 | Practical Electronics 19
106 | Henry’s Radio 12 | Protechnic 28
gg | HL Audio 28 | ;
72,73 | Integrated Circuits Unlimited 25 Be neni ees s
404 | Interactive Sciences 23 | Robox (Office Equipment Systems) 128
g2 | Interam Computer Systems 10 | Rostronics Computer Centre 78
Isherwoods 8
' , Science of Cambridge 64
66 i i 26 :
ee Jilta Micro SEED 48
21 | Keen Computers 52 | Shelton Instruments 26
Kingsland Electronic Services 16 | Sintrom Microshop 11
108 Sirton Products ' 24
107 | Leenshire 107 | Small Systems Engineering 18 |
100 | Linburg Electronics 1g | Software House, The 58
109 | Lion Computer Systems 4 | Source : 96
16 | London Computer Store 106 | Stack Computer Services 32
56 | Lotus Sound 34 | Strathand — 14
18 | LP Enterprises 7,22 | Strutt Electrical & Mechanical
132 | LTT Electronics 24 Engineering : 108
15 | Lyme Peripherals 124 | Sumlock Electronics Services 6
134, 135
14 | Marshalls 6 | Tangerine 12
74 | Microbits 20 | Tay Commercial Services 102
102 | Microcentre 92 | Technalogics 22
136 | Microdata 96 | Terminal Display Systems 104
31 | Micromedia (Systems) 58 | Tim Orr i 26
10 | Microsoftware Systems 24 | Transam 29
30 | Microsolve Computer Services 123 | T&V Johnson (Microcomputers Etc) 61
<3 Midwich Computer Co 126
Millbank 16 . :
124 | Mine of Information 22 vate Terminals 14
Monodiand 51 ideotime Products 10
83 Viasak Electronics. 132
66 | Naéoo Sales 17 | V&T Electronics 132
62 | Newbear Computer Store 74 .
130 | NIC Models 100 | Watford Electronics 40
Wyeside Computing 16
9, 28,104 | OMB 6
2 | Optronics 108 | Shop Window 113-122
133
PRACTICAL COMPUTING July 1979
FREE B BUG
valued at £23.00
plus 10 x C12 cassettes
valued at £4.00
plus Standard Modulator
INTERESTED
IN HOME
COMPUTING? | wn vsstoy
Start now and don’t get left behind THE NASCOM 1
is here Ex-stock with full technical services
Plus the opportunity to join the fastest moving club of personal
computer users enabling you to get the most our of your
computer. You can OBTAIN and EXCHANGE programs and
other software — many now available.
The Powerful Z80
Microprocessor
Professional Keyboard
1 Kbyte Monitor in EPROM
2 Kbyte RAM (expandable)
Audio Cassette interface
Plugs into your domestic TV
Easy construction from
straightforward instructions
— no drilling or special tools
— Just neat soldering
COMPUKIT UK101 -» =
All specifications of Superboard with many improvements and in
kit form including power supply and modulator on board. Improved
video display with 48 chars x 16 IIlnes. English TV Standard.
£219
+ VAT
SEND £10 DEPOSIT TO RESERVE
OHIO SUPERBOARD I NEWS ox'cewo
For electronic buffs. Fully assembled and tested. Requires +5V at
3 Amps and a video monitor or TV with RF converter to be up and
running. STANDARD FEATURES
Uses the ultra powerful 6502 microprocessor
8K Microsoft BASIC-in-ROM
Full feature BASIC runs faster than currently
available personal computers and all
8080-based business computers.
RELEASED END OF
JUNE 1979.
required, j pas Static RAM on board expandable to 8K
rs ‘ Fi ull 53-keyboard with upper/lower case and user
Only £19450 + 8% VAT (includes p & p + insurance) oregrafnriablli ts
Manuals seperately 2.95
Kansas City standard audio cassette interface
for high reliability
Full machine code monitor and I/O utilities in
ROM
Direct access video display has 1K of dedicated memory (besides
Z80 programming Manual 6.90
280 Technical Manual 2.95
PIO Technical Manual 2.95 Power supply suitable for
(All prices add 8% VAT) NASCOM 19.90
NEW LOW PRICE
£165 + vat
NASCOM AD ONS — Nascom improved monitor B Bug (2K)
featuring — *Four times tape speed *Direct text’entry without
ASCII *Extended keyboard facility “Additional useful
subroutines £23.00
Nascom Vero Case Nascom Music Box Kit £9.90
£22.50 (write your own tunes and play
Nascom Joy Stick Kit them on your Nascom.
£14.90 Complete with full documentation).
GRAPHICS ADD ON BOARD £9.90
Complete kit to upgrade your NASCOM for graphics capabllity
includes full documentation and demonstration program.
NASCOM IMMEDIATE
EXPANSION S100 from COMP
—strongly recommended
The only available $100 motherboard kit (fully buffered) that
plugs directly into your Nascom. Designed for the insertion
of S100 boards (e.g. Static RAM, EPROM and discs etc.).
$100 Motherboard/Buffer £47.50 ) Motherboard
(Complete kit + documentation) ah pa, sabi
Suitable 8K Static RAM Memory-842&£110 ( “Bacic on”
(fully assembled tested and guaranteed) cassette.
NASCOM LOW COST EXPANSION
Uses dynamic RAM and NASBUS
(please note this expansion does not support S100 memory)
Tiny Basic in EPROM £25.00
8K Dynamic RAM board (in kit only) £85.00 | (ius
Motherboard (in kit only) £12.50 VAT
Buffer board (in kit only) £25.00
SHORT C12 CASSETTES 10 for £4.00
FOR COMPUTER PROGRAMMES
SPECIAL DYNAMIC
MEMORY OFFER <0?
8x 4116 o
1hOns access time, 32Mns ecvrle
134
MODULATORS UHF Channel 36
INDUSTRIAL POWER SUPPLY
+5v 10 amps — £63.25
DC switched
TRS 80 SOFTWARE
100 MIXED PROGRAMMES
HITACHI 9" & 12”
PROFESSIONAL MONITORS
4K user memory), features upper case, lower case, graphics and
gaming characters for an effective screen resolution of up to 256
by 256 points. Normal TV's with overscan display about 24 rows
of 24 characters; without overscan up to 30 x 30 characters.
EX-STOCK — £263 var
Please phone to check availability or send £10 to
reserve one and pay the balance on delivery
Standard 6 meg band width £2.25
High Quality 8 meg band width £4.90
+5v 5amps + 12v-12v-5v £89.00
Both, housed and fully guaranteed. Lightweight
NEW
ARK KF FRR PASI Ms PRATT IO LIPOIC! I OCIA IIe
on cassette
SUPERB DEFINITION
” — £132] ,
12" — £210) ™
Delivery charged at cost — Red Star — Securicor — Post etc., Your
Choice, Please make cheques and postal orders ayable to COMP, or
phone your order quoting BARCLAYCARD or ACCESS number.
OPEN — 10am to 7pm — Monday to Saturday
CONTINUOUS DEMONSTRATIONS mee (~s-2 +)
=
PRACTICAL COMPUTING July 1979
JONNY FUN VU OPMING 19 CGAIALUUVE UV OUP
JUST COMPARE OUR CASH AND CARRY PRICES!
THE TRS-80 (SPECIAL SCOOP) ) ATTENTION! save eso wes
Low Priced, Ready toGo! » TRS 80 & APPLE II USERS 7":
= 16K UP ua
GRADE KIT omc £99 LIFETIME
NEW Standard QWERTY
Keyboard with 16K Memory
Use your own cassette
Level-Il with 4K RAM ii.
Improved graphics, print
formatting, and a faster cassette
transfer rate are features of
Level-l1 BASIC.
PLUGS INTO
YOUR OWN TV }
Level-l] with 16K RAM
A combination of 16K RAM and +
the powerful Level-l! BASIC VAT
produces a system capable of
handling most demands.
FREE 100 PROGRAMS The No. 1
in the U.K.
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8K PET still at
UK POWER SUPPLY — £9.90 - var unbeatable price of £499 + var
THE EXIDY SORCERER. (s;,
SORCERER gy
COMPUTER SYSTEM (eu)
The Sorcerer Computer is a completely
asseMbied and tested computer system
Standard configuration inctudes 63-key
typewriter-style keyboard ana 16-key
numeric pad, Z80 processor, dual cassette
1/0 with remote computer control at 300
and 1200 baud data rates, RS232 serial 1/O
for communications, paralle! port for
direct Centronics printer attachment, 4K
ROM operating system, 8K ROM
Microsoft BASIC in Rom Pac™™, cartridge,
composite video of 64 char/line 30 line/ LOOK!
screen, 128 upper/lower case ASCII set *32K RAM on board
and 128 user-defined graphic symbols, °RS232 interface “8K BASIC ROM
Operation manual, BASIC programming “CUTS interface *4K MONITOR
manual and cassette/video cables, connect- “KANSAS CITY interface *S100 BUS
lon for S-100 bus expansion “User defined graphic symbols °Z80 cpu
EXIDY SORCERER 32 ramcomeuter £79O vir
BOOK SHELF 8080A Bugbook Interfacing &
Programming by Rony, Larsen &
NEW! THEITT APPLE (2020)
LOW PRICES FAST SERVICE! Titus (1977) 416 pages £6.90
EX STO C K 4 K Vol 0 The Beginner's Book . 2 £5.40 280 Programming for Logic Design
Vol t Basic Concepts + ..... £5.90 by Adam Osborne...... £5.90
Vot 2 Some Real Prades (June Z80 Microcomputer Handbook by
LOW P R | C c M E M O RY U PG RAD E ode £9.90 Sree & Problem une
Microprocessor series, by Rodney Solving with Pascal
PURCHASED AT TIME OF ORDER Serene wae ESN ee upmansos
Microprocessor Systems Design by microcomputer speak Pascal”..... £9.50
* : . i Ed Kil an [SBN 0-135-81413-8 BASIC Computer Games —
came eer pie | a ae (1977)480 pages hardcover........__ 16.40 Microcomputer edition... £5.40
es RAM on Bode * BASIC in fom CMOS Cookbook by Don Lancaster £6.90 Best of BYTE Vol 1(1977)376 pages £8.90
* (graphics commands include “6800 Assembly Language Best of CREATIVE COMPUTING
Q OLOUR = VLIN, HLIN, PLOT and Pcl) 56. SSS et £6.50 Vol 1(1977)326 pages ....... .. £6.90
¢ SCRN) * Built in Loudspeaker 6800 Software Guide & Cookbook Vol 2(1977) 323 pages ........ £6.90
RT “Buckets of software already Be eel ene wears £7.90 MOI OTHELLO Game for 2 players
= available "disk system (110 K byte from Scelbi .. £7.90 on NASCOM 1 cassette... .. £2.00
per drive — includes controller) only 8080 A/B085 Assembly Language MOI MINO PILOT powerful text
£425 + VAT Programming £6.50 editor and interpreter in ¥2KB!.. £5.00
For technical and sales literature send SAE to: TAKE ADVANTAGE OF OUR
COMP COMPUTER COMPONENTS (Exidy UK Sales), SHORT DELIVERY TIME.
Freepost, 14 Station Road, New Barnet, Herts. :
Tel: 01-441 2922 (Sales) 01-449 6596 Telex: 298755 All prices exclusive of VAT
(PART OF THE COMPSHOP LTD. GROUP)
@ Circle No. 309
PRACTICAL COMPUTING July 1979 135
[36
CT-82 Terminal
The CT-82 has 128 different functions all of
which are software controlled. Too numerous to
list in their entirety they include 18 cursor
control commands, 6 ways to configure the
cursor, 11 erase functions and graphics
capability including point-to-point plotting, field
protection, printer pass through, paged edit
mode and light pen position reading.
Computer Workshop
3rd Anniversary Offers
4K Memory board (Can be
used with Motorola D2 kits Kit£45.00
as well as SWTPC) Ass£50.00
Tubes of 25.x 2102-L. RAM £20.00
6575 Character Generator £4.00
Set of 20 male and female Molex
10 way connectors £6.00
MP=A processor board containing
6800 MICBUG system, clock and
128 byte scratchpad RAM Ass £50.00
All prices include postage, packing and VAT.
All offers: subject to availability. Please send
-cheque with order. Goods or full refund by
return.
* Software function controls
* 56-key “Cherry” keyboard
* 12 key numeric or cursor
control pad
* 128 control functions
* Graphics capability
* User programmable
character sets
Software selectable Baud
rates (50-38, 400)
<
£550 + VAT
PR-40 Matrix Printer
This unit can be used with any computer with a
parallel printer interface and may be ordered
with a special interface for the PET system.
The PR-40 uses an 8 bit parallel interface, with
data strobe and acknowledge.
This unit prints the 64 character upper case
ASCII set on a 40 character line at a print speed
of 55 lines per minute. It uses-an impact dot
matrix head and prints on standard adding
machine paper. It is ideal for development work
and applications where a 40 column report is
sufficient.
PR-40A (25 way RS connecto) £250 + VAT
PR-40P (PET connector) £250 + VAT
Sul
Southwest Technical Products Co.
cw
Computer Workshop
38 DOVER STREET - LONDON - WX 3RB - Telephone: Ol-491 7507 - Telex: 268913
@ Circle No. 310
Ll.
MEANS MICROCOMPUTERS
25 Sea, Te STREET
| nt LIVERPO OBJ ND
Tel: 051-236 Soutien | Order) EMS oe
Tel: 051-227 2535 (All other Depts.) baer ( PAA oa "g
a "SPEC HENS no. ome Pu
so
-_ a :
eno
A2
Introduction
MICRODIGITAL LIMITED
WHERE TO FIND US
IN LIVERPOOL
Victo@ ia MONUMENT
Our company is one of the first in the country set up to cater for the exciting
new world of microcomputer.
We sell a wide range-of computers, each selected for its value, ability and
reliability, brief notes of each are included on the following pages.
Not only do we serve as a retail outlet for the machinery of the second
industrial revolution but also we offer a myriad of other service to help you to
decide which machine best fits your requirements, this is backed by providing a
hire service which allows potential customers to try a machine before they buy it.
Secondly we sell the widest range of literature concerning microcomputers
available in the U.K. today. The books are imported directly from the U.S. and our
current range exceeds 250 titles. Magazines include all the U.K. magazines with as
many back issues as possible held in stock. The best of the American Magazines
are also available, the latest possible issues always being in stock.
On the hardware side we have the proven ability to design, manufacture,
maintain and repair; likewise on the software side we have the proven ability to
produce and maintain commercial application programs.
In addition to all the foregoing we also provide support with magnetic media,
engineering tools, test equipment etc, etc.
All in all we try ard provide the most competent service in the
microcomputer industry.
TERMS AND CONDITIONS
In addition to cash we accept Access, Barclaycard, Diners Club and
cheques covered by a bankers card.
VAT in this brochure has been calculated at the rates of 8% and
12% current at the time of writing. Please allow for any changes
in the rates.
Postage and carriage is offered free of charge within the United
Kingdom.
All products are covered by our 90 limited warranty against
failure due to faulty materials or workmanship.
We offer an after sales service which is second to none, technical
expertise is always available from our well informed staff and
repairs are handled by our own service department at very
competative rates. <e
Terms are implemented at the discretion of ey
management.
‘
BRUCE EVERISS
TECHNICAL QUERY SERVICE
We have a free technical query service,
for written queries only. If you have
any question you want answered
write us a letter and we will reply with
your answer by return of post.
WHY YOU SHOULD BUY FROM US
We want and appreciate your trade.
As a direct consequence of this, we
do our upmost to ensure that our
customers are, and remain, happy. To
this end we provide full technical
support with fast and efficient service
for all our customers.
(x commodore
the Commodore Pet
A complete Computer for the price of a
good typewriter! With a library of over
200 programs in business, science,
education and entertainment costing as
little as £1.25 each.
The Pet is made with Commodore's own
advanced technology to bring you the
benefits of recent dramatic advances in
microprocessor technology.
Pet can store and retrieve data which
conventially occupies hugh storage
capacity, and solve numerical
problems traditionally tedious
and time consuming.
COMMERCIAL APPLICATIONS
The Commodore PET brings to the commercial user for the first time, a realty
cost effective business computer for use in payroll, stock control,
amortization calculations, numerical analysis, etc.
FOR THE SCIENTIST AND ENGINEER
The PET has a comprehensive set of scientific functions designed for
scientists and engineers. PET also has a built-in real time clock and is
directly compatible with hundreds of instruments such as D.V.M.'s,
dataloggers etc., enabling control of industrial plant and processes.
AS A TEACHING TOOL
Asa teaching tool in computer programming and other fields, the PET has
no equal in performance or cost. There is even a tutorial programme (Basic
Basic) available for £8.00 — use the PET to teach you how to program PET!
COMPUTERS
IN THE HOME
As well as being used for all the previous applications the PET computer is
an extremely creative and instructive learning medium of the future for
young and old allke. There are also large numbers of entertainment
programs available including chess and space games.
EASE OF OPERATION
The Commodore PET comes complete with a built-in T.V. screen, keyboard
and cassette deck as well as its full computer circuitry. It is plugged into any
13 amp mains and no special computer knowledge is needed for running
standard programs. Personal programs can readily be written in the BASIC
computer language of PET which is easily learnt.
AN EXPANDABLE SYSTEM
Further expansion is a prime design Concept enabling PET to be made the
heart of & much larger system incorporating printers, floppy discs etc, as
and when required.
Total
£
-PET 2001-4 Standard PET with integrel cassette and calculator type keyboard. : 496 80
4K bytes of memory. .............%...... Aon Soe
‘PET 2001-8 “ Standard PET with -integral cassette , and ‘eatewlotor S¥pe keyboard’
8K bytes af MOMOMY. ... 6-0. 2 eee Sere ce eee eee ee a ie ee . 6 0 i r 594.00
PET 2001: 16N — BET with T6k bytes of memory and large Keyboard. Extemal cassette aap 75. ¥ 729.00
PET 2001- 32N PET with 32K bytes of memory and large keyboard. External’ cassette optional : : 858:60
PRINTERS
PET 2023: 80 column dot matrix printer. Plain paper printer with full PET graphics. ......°. ( 594.00
PET 2022 80 column dot matrix printer as above,. with forms" Ranidling <capability 696 60
and tractor feed.
FLOPPY DISC
PET 2040 — Dual drive intelligent mini-floppy system. 343K net user storage capacity. : . 799. 20
EXTERNAL CASSETTE DECK
PET C2N
KIM RANGE
KIM 1 Microcomputer System
KIM 3B 8K Memory Expansion
KIM 4 Motherboard
MANUALS (VAT free}
PET Introductory Booklet
PET Users Handbook
6500 Programming Manual
6500 Hardware Manual
KIM Users Handbook
Strathclyde Basic Course Workbook (Without cassettes}
MISCELLANEOUS
PET Users Club Membership
included with PET Computer
‘included with KIM 1
59.40
107.95
140.35
75.55
1.00
5.00
5.00
5.00
5.00
3.00
70.00
PART EXCHANGE
Nascom 1 owners — We will-give upto £165 in
part exchange for a well built, working Nascom
1 against the cost of a Commodare Pet.
wa
=e '™°- SORCERER
EXIDY SORCERER is a complete and ready to use microcomputer, simply plug into a standard
U.H.F. T.V. set and you are up and running in BASIC.
SORCERER is manufactured in America by EXIDY who have for the last five years been a
leading manufacturer of microprocesser based T.V. games.
High quality materials are used throughout, and the SORCERER has proved to be a well
constructed and reliable machine.
Subject of rave reviews, SORCERER offers far and away the best features of any machine in it’s class.
FEATURES AS STANDARD
In alphabetical order:
BASIC.
SORCERER has 8K Microsoft BASIC, contained in a plug in “Rom Pak”
which slots into a socket at the side of SORCERER. Microsoft BASIC is a well
tried and trusted version of BASIC used on a number of other machines
besides SORCERER.
CHARACTERS.
SORCERER has the full 128 character, upper and lower case standard
ASCII. and also 64 useful predefined graphic characters.
DISPLAY.
The video display on SORCERER is “memory mapped”, the characters
dispiayed on the screen are a representation of a block of random access
memory. This feature is very useful when working with graphics.
64 characters are displayed per line, and 30 lines canbe displayed at once
a total of 1,920 characters all seen at the same time.
GRAPHICS.
This is an area in which SORCERER scores high marks in the computer
ratings SORCERER has 128 graphic symbols which may be defined by the
user on an 8 x 8 dot matrix. Any symbol may be defined such as a
mathematical symbol, part of a larger picture made up of many such
symbols, or even a chinese letter! .. . Yes your computer can even speak
chinese!
Each user defined character is formed by programming 8 bytes of memory
and is assigned a key on the keyboard depending on where in the memory
you place the 8 bytes of data. User defined graphics may be called up direct
from the keyboard or under program control.
KEYBOARD.
SORCERER has a high quality keyboard with a light but positive ‘‘feel”’ to
it. The keyboard consists of a 64 key, stepped, style keyboard with a 16 key
numeric keypad to one side, the numeric keypad is very useful for
programmes containing a great deal of number data.
MEMORY EXPANSION.
The standard SORCERER unit has 8K of user Ram. The memory capacity
may be expanded to 16K or 32K without any additional hardware save the
chips themselves, further expansion is available via the S100 expansion
unit which is an optional extra.
MONITOR.
SORCERER has a power of 4K monitor in Rom. Facilities include, Memory
display/ modification, Input/output control (for instance you can link to user
defined I/o routines), cassette file handling and creation of batch tapes.
memory block move and system diagnostics.
PARALLEL INPUT/OUTPUT.
A(DB 25) 25 pin connector at the rear of SORCERER provides a parailel
input/output port which can drive a Centronics printer or similar peripheral
devices that require an eight bit parallel |/O port with full handshaking.
ROM PAKS.
There are a unique feature of the SORCERER, the Ram Pak provided with
the SORCERER contains 8K Microsoft BASIC in Rom. APL, FORTRAN pascal
in Rom Paks are in the pipeline also Eprom pak, Development Pak, and Word
processing Pak will be available inthe future. ROM Pakscancontainas much
as 16K of read only memory.
SERIAL INPUT/OUTPUT.
Standard RS232 serial output is available via another DB 25 connector at
the rear of SORCERER, this socket also has connections for two
cassette units furthermore the motors of these cassette units can be
controlled by instructions contained in your programmes.
$100 EXPANSION UNIT.
The $100 expansion unit is a self contained 6 slot chassis styled in the
SORCERER fashion with interconnect cable and s*100 transaltion
interface. It serves to connect SORCERER to a standard bus structure
enabling SORCERER to be connected to a multitude of peripheral devices
inctuding: Printers, Floppy Disk Subsystems, A.C. power line switching,
‘Music Synthesizer units, Speech Recognition systems, Speech synthesizer
units, and many other exciting devices.
TAPE INPUT/OUTPUT.
Facilities are provided on the SORCERER for connection to a standard
commercial tape recorder. Just plug into the earphone and microphone
sockets (leads provided) thls gives you the abllity to store and retrieve
programmes you have written.
VIDEO OUTPUT.
Jack plug connectors at the rear of the machine give both modutated and
un-modulated video.
RETAIL TOTAL
PRICE(E) VAT IE) (£)
Sorcerer Computer 8K RAM 650.00 52.00 702.00
Sorcerer Computer 16K RAM 760.00 60.80 820.80
Sorcerer Computer 32K RAM 859.00 68.72 927.72
Sorcerer Computer Expansion.
$100 Expansion Unit.
A completely self-contained 6-siot chassis styled in the Sorcerer
fashion with interconnect cable and $100 translation interface.
RETAIL TOTAL
PRICE(£) VAT(E) (€)
$100 Expansion Unit 210.00 16.80 226.80
Video Display Unit
A 12" professional CRT monitor with high resolution and P31
phosphor styled in the Sorcerer fashion. Connects directly to Sorcerer
computer with video cable supplied.
RETAIL TOTAL
PRICE(£) VAT (E) (€)
12" Video Display 240.00 19.20 259.20
14D Expansion Kit
A cable and $100 transtation interface card to Interconnect any $100
chassis to the Sorcerer computer.
RETAIL TOTAL
PRICE (E) VATE) (€)
1/0 Expansion Kit 98.00 7.84 105.84
16K Memory Expansion Kit
Component parts and instructions to ADD-ON memory within the
Sorcerer computer enclosure. Maximum RAM expansion internally
is 32K bytes.
RETAIL TOTAL
PRICE (E) VAT(E) (€)
16K Memory Expansion Kit 175.00 14.00 189.00
Sorcerer Computer Accessories RETAIL
Manuals PRICE (£)
Sorcerer Operation Manual 6.95
Sorcerer Technical Manual 8.95
Standard BASIC Manual 8.95 No VAT on
Development Tour Manual 8.95 these items
Word Processing Manual 8.95
$100 Expansion Unit Manual 6.95
Video Display Manual 6.95
Rom Pac TM Cartridges
EPROM Pac 35.00 2.80 37.80
Standard BASIC Pac 70.00 5.60 75.60
Development Pac 70.00 5.60 75.60
Word Processing Pac 70.00 5.60 75.60
Miscellaneous
Cassette Recorder Cable 3.95 0.32 4.27
Video Display Cable 3.95 0.32 4.27
Serial/ Cassette Data Cable 16.95 1.36 18.31
Parallel Data Cable 16.95 1.36 18.31
Apple Il
Features
A tast powerful integer BASIC is
built into Apple Hl. The built-in
assembler, disassembler and
monitor will be appreciated by
advance programmers in search
of more speed or flexibility than
BASIC can provide.
Fifteen colour standard graphics
in a 1,880 Point array for
spectacular visual effects.
* High resolution graphics in a
54,000 point array for finely
detailed display.
* Loudspeaker and sound
capabilities that bring programs
to life.
* Four hand control inputs for
games and other human input
applications.
Internal memory capacity of 48K
Bytes of RAM, 12K Bytes of ROM
for big system performance in a
small package.
Eight expansion siots to piug in
cards that give your Apple even
more power.
‘Superb, easy to foliow documenta-
tion, so even a total beginner can
use the machine.
* Fast (1500 baud)
interface.
* Proper typewriter style keyboard.
Apple Il prices
With 16K of RAM
Nett. Vat. Total
985.00 78.80 1063.80
With 32K Bytes of RAM
1185.00 94.80 1279.80
With 48K Bytes of RAM
1305.00 104.40 1409.40
Applesoft II Floating
Point BASIC
An expanded version of Micro-
soft’s popular floating point
BASIC. its 9 digit arithmetic and
large library make it Ideal for
business and scientific programs.
Applesoft {i is supplied either with
a cassette tape or a plug in ROM
card. The tape version is supplied
free with every Apple.
Apple Ii ROM card
cassette
110.00 8.80 118.80
Floppy Disk
Subsystem
Gives your system immediate
access to large quantities of data.
The subsystem consists of an
Intelligent interface card, a
powerful Disk Operating System
and one or two mini-floppy drives.
Features
* Storage capacity of
Kilobytes/diskette.
* Data transfer rate 156K Bits/
second.
Individual file write protection.
Powered directly from Apple 11.
Full disk capability with systems
as little as 16K bytes of RAM.
* Fast access time — 600 m sec
(max) across 35 tracks.
Powerful disk operating soft-
ware.
* Load and store files ;by name.
* BASIC program chaining.
* Random or sequential file access.
Floppy disk subsystem
25.00 34.00
116
»
>
459.00
Second disk drive and connecting
cable
375.00 30.00 405.00
Parallel Printer
Interface Card
Allows you to connect almost any
popular printer to your Apple, A
BASIC program can produce hard-
copy output as easily as it prints to
the TV monitor screen. Command
interpretation and printer controi
detalls are handied by the firmware
built into the card, to eliminate
user programming requirements.
Parallel Printer Interface Card
Nett Vat Total
110.00 8.80 118.80
Communications
Interface Card
Allows your Appie to “talk”
{though a modem) with other
computers and terminalis over
ordinary telephone lines. Now you
can load programs over the phone,
send messages to remote
terminais or access your office
computer from the comfort of your
home.
Communication Interface Card
Nett Vat Total
110.00 8.80 118.80
High Speed Serial
Interface Card
Allows Apple to exchange data
with printers, plotters and
computers in serial format at up to
19.2 K Baud
High Speed Serial Interface Card
Nett Vat Total
110.00 8.80 118.80
Speechlab Voice
Recognition Card
Allows the Apple to recognise a
spoken vocabulary of up to 32 user-
selected words. The computer can
be programmed to perform any
task desired upon recognition of a
key word.
Voice Recognition Card
Nett Vat
165.00 13.20
Prototyping Card
Provides the User with a means of
building up experimental circuitry
for the Apple computer. The 2%” x
7” double-sided board includes a
hole pattern that accepts ail
conventional integrated circuits
and passive components.
Documentation includes a
complete system bus description
to aid the interface designer.
Total
178.20
Prototyping Card
Nett Vat Total
18.00 1.44 19.44
Carrying Case
The Apple is truly portable and this
padded vinyl, leather look case
protects your Apple in transit and
makes it easier to carry.
Carrying Case
Nett Vat Total
25.00 2.00 27.00
BARCLAYCARD
nea
accepted
apple I=VWICRODI
JOIN THE MICROCOMPUTER REVOLUTION
BY BUYING THE BEST
APPLE PLUGS INTO A DOMESTIC TELEVISION —
CASSETTE RECORDER TO MAKE A
POWERFUL, EASY TO USE COMPUTER SYSTEM
Other Products
Apple maintains a 6 to 12 months
technology lead over the
competition. There is not sufficient
space to give full details of all that
is available, but.the following is a
sample to whet your appetite.
Light pen
Real time clock
Co-resident assembler on disk or
tape
TAL
—-
Software
We can supply application
Programs from a number of
sources and advise you on your
program requirements.
Our own software department has
developed a Trade Counter
program which keeps a round
pounds debtors ledger in real time
and advises trade counter staff
Prag rarimibbig aid ROM when Credit limits are reached.
Joysticks This program is tried, tested and
PROM Burner proven and helps reduce bad
. debts.
Apple Hire Nett Vat Total
The Apple is one of many sgl gi 7—
Trade Counter Program (integer
basic, needs 32K of RAM and a
single disk)
machines from Microdigital (Hire)
Ltd. For detalis ring 951-227 2535.
Lower case for your Apple II
exclusively from
MICRODIGITAL
Plugs in — no modifications to yous Apple
Displays lower case letters with descenders
Provides full 96 — character ASCII set
Software included for use withinteger BASIC.
kK K x
VAT
3.20
Nett
40.00
Total
43.20
NEWS FLASH
ITT 2020 SYSTEM
We are now dealers for the ITT version of the Apple at the
following prices.
Lower case adapter
Nett Vat Total
With 4K Bytes of RAM........... 827.00 66.16 893.16
With 16K Bytes of RAM.......... 950.00 76.00 1026.00
‘With 32K Bytes of RAM.......... 1114.00 89.12 1203.12
With 48K Bytes of RAM.......... 1278.00 102.24 1380.24
PART EXCHANGE
Pet owners, trade up to an Apple at MICRODIGITAL. We can
allow up to £300 for your old PET against the cost of a new
Apple Il
Other Prices
8x 4116 RAMS 16K Bytes .
Joystick
Diskettes
8.00
1.60
Tractor feed on Printers
British ASCLI on Printers
AXIOM micro Printers..........
AXIOM graphics Printers ..... :
Books
a 1.76
27.92
Apple operators manual ........ 5.50 NO VAT ON
Applesoft extended THESE
Basic manual ...........- ‘5 4.00
BWsic RUtOr): ... «Se siiels sea kee. 4.00 ITEMS
6502 programming manual... .. 7.50
66502 hardware manual......... 7.60
Ab
Nett VAT Total
NASCOM! .... 165.00 13.20 178.20
The Nascom | is the best possible introduction tothe
world of personal computing, yet it has the power and
flexibitity to be expanded into a full data processing
system.
The specification includes a powerful-Z80 processor,
paraliel 1/0 controller with two 8 bit ports. UART
driving cassette interface or most serial peripherals,
video outputto plug in the ariel sockets of your T.V., 2K
bytes of RAM (1K user and 1K video), proven 1K byte
monitor program in EPROM and a spare EPROM
socket.
The kit is complete, all that is required is a power
supply a domestic T.V. and a domestic cassette
recorder.
POWER SUPPLIES
There sre two power supplies available, a 3 amp
supply which will power the basic kit and some
expansion and an 8 amp supply with toroid
transformer which will power a very large system.
Both supplies can be mounted in the vero frame.
Nett VAT Total
AS teense 24.60 1.96 26.46
8 amp P.S.U
KITES: cucu dle. . 60.00 480 64.80
EXPANSION
Nascom | is expanded by connection to a buffer board
which creates a 77 way bus structure "NASBUS" into
which expansion boards plug directly. The bus
structure is carried along a motherboard which allows
future boards to be added and to keep your computer
neat the Nascom I, power supply, buffer board, mother
board and expansion boards can ali be mounted ina
vero frame,
Board.......... 32.50 260 35.10
board.........- 960 076 10.26
Mini
Motherboard... . 2.90 0.23 3.13
frame........-- 29.50 2.36 31.86
NASBUS
The 77 way Nasbus has the following advantages:
1. Uses standard Veroboard as a motherboard and
Standard 0.1” single sided edge connectors for
expansion cards. These components are readily
and cheaply available.
2. The bus structure leaves 8 spare data lines and 4
spare address lines for future use of 16 bit
processors.
3. The power lines are regulated, on board
regulators. are therefore not needed which
obviates the necessity for fan assisted cooling
4. Al cards use lower power, low noise shottky
buffering which means the bus is quiet anddoes
not need sophistication like active termination
or interleaved ground planes.
5. Expansion boards are standard 8” x 8" vero DIP
boards which are economic and give a good
useable area.
MEMORY
The memory expansion board can carry 16 dynamic
RAM chips, these can be either 4K bit or 16K bit chips
and the board is offered with 8, 16 or 32K bytes of
RAM. The 16K board can be expanded to 32K by
plugging in 8 more 4116 chips.
The memory expansion board also has room for 4
2708 UVEPROMS each of 1K bytes and a lot of pre-
programmed systems software is available to fitthese
sockets.
Nett Nett VAT Total
board! Kr ey. me. 86.00 680 91.80
el la .. 140,00 11.20 151.20
pa oy 200.00 16.00 216.00
gs 4116 eres 70.00 560 75.60
2708 ‘= 10.60 084 11.34
INPUT/OUTPUT
For people wanting to use more peripherals than the
standard kit allows for, Nascom are producing an 1/0
board which can carry a counter timer chip and a
number of PIO’s and UARTS.
This will be available in March.
1/0 board...... 35.00 280 37.80
(oe 8.00 0.64 8.64
UARI perce 6.60 0.44 5.94
=e 8.00 0.64 8.64
BASIC
To allow high level language programming Nascom
have produced a 2K Tiny basic and a 3K Super Tiny
Basic in 2 or 3 2708 EPROMS respectively. Also
available is an 8K Microsoft precision floating peint
basic in 8 2708's which will be available in June on a
single 64K bit ROM to fit the EPROM board.
Basic .......... 25.00 2.00 27.00
Basic .......... 35.00 280 37.80
(Bx 2700) oe 100.00 8.00 108.00
(ROM).......-. 40.00 3.20 43.20
EPROM BOARD
Available in June this board will carry 8 x 2708
UVEPROMS and the 64K bit ROM containing basic.
The board can also be used for burning in 2708
UVEPROMS.
The most successful
microcomputer in Europe, the
Nascom 1 represents
exceptional value for money.
NRO EL WVICRODIGITA
BOARD........ 40.00 3.20 43.20
GRAPHICS BOARD
Allows high resolution graphics on your Nascom 1.
Contains 4K of RAM.
GRAPHICS
BOARD 96.00 760 102.60
MONITOR
Nascom have written a new monitor, T4 the most
powerful yet available for this machine it contains
many desirable features not found on any other
monitor. T4 comes in 2 x 2708 to plug into the main
Nascom 1 board.
Nett VAT Total
NasbugT4 26.00 200 27.00
ASSEMBLER
A powerful editor assembler zeap 15 available to run
under Nasbug on tape.
(tape) .......... 30.00 240 32.40
M5
This is a new computer language, designed to use the
minimum amount of memory andthus work on abasic
Nascom 1 Kit.
Features
* Reverse polish notation
* Multiply, Divide, Add, Subtract, Increment and
Decrement by one,
Integers up to 64K.
Variables AtoZ
Loops and jumps
Editor
Error messages
String handling
MS is supplied on tape with an instruction manual
packed with examples and a hex dump of the
language.
We have priced M5 soall Nascomowners can afford it.
9.26 0.74 10.00
{M5 is supplied free on all Nascom purchases overthe
value of £150}.
THE FUTURE
In the near future a mini-floppy disk system will be
available with either single or double drive. These will
probably offer in excess of ‘4 a megabyte and 1
megabyte respectively at prices that will allow even
thet to have a large data base. Totakefull advantage of
the business and scientific uses opened up by disks
Nascom intend to release several high level
languages. Looking further forwards Nascom is a
devetoping product. and the fact that manythousands
are now in use will ensure thatthe latestin computer
technology will be available at a competitive price.
FREE Gift Pack
with all Nascom I purchases over £150.
Contains:
A copy of M5, pad of 100 Microdigital coding
forms, 10 CI5 cassettes, keyboard bleep kit,
UHF modulator and keyboard ribbon cable.
Total Value nearly £30.00
which was launched nearly 18 months ago, Nascom
Microcomputers Limited has introduced the NASCOM-2.
In no way is the NASCOM-2 a replacement for the
‘NASCON.-1. Over the 18 month period, it has become
obvious that there is a marketplace for the NASCON.-1 for
the forseeable future. However, there is also
a large market for an upgrade version which
will have more of a computing bias. From
this specification you will see that many of
the additions necessary on the NASCOM-1
are integral in the NASCON-2.
MICROPROCESSOR
Z80A. 8B bit CPU. This will run at 4 MHz butis selectable between 1/2/4 MHz.
This CPU has now been generally accepted as the most powerful, 8 bit
processor on the market.
The software library for the Z80, with its base around the 8080, has rapidly
expanded with the increasing use of its more powerful instruction set.
HARDWARE
12” x 8” Card
All bus lines are to the Nasbus specification.
All bus lines are fully buffered.
PSU +1 2v, +5v, -12v, -5v.
MEMORY
On-board, addressable memory: 1K Work space/User RAM (MK 4118)
2K Monitor — Nas-Sys 1(2K ROM) 8K Microsoft Basic (MK3600 ROM)
1K Video RAM (MK 4118) 8K Static RAM/2708 EPROM
a
INTERFACE’ KEYBOARD
New expanded 57 key Licon solid state keyboard especially built for Nascom.
Uses standard Nascom, monitor controlled, decoding.
T.V.
The 1v peak to peak video signal can drive a monitor directly and is alsofedto
the on-board modulator to drive the domestic T.V.
1/0
On-board UART (Int. 6402) which provides serial handling for the on-board
cassette interface or the RS2 32/20mA teletype interface.
Thecasette interfaceis Kansas Citv standard ateéither 300 or 1 200baud. This
is a link option on the Nascom —
The RS232 and 20mA connector will interface directly into any standard
teletype.
The Posi and Output sides of the UART are independently switchable
between any of the options—
i.e. Itls possible to house input on the cassette and output on the printer.
PIO
There is also a totally uncommitted Parallel I/O (MK3881) giving 16,
programmable, I/O lines. These are addressable as 2 x 8 bit ports with
complete handshake controls.
ON-BOARD DECODING
The NASCOM-2 makes extensive use of ROMS for on-board control
decoding. This reduces the chip count and allows easy changes for
specialised industrial use of the board.
Link options are on-board to allow the Reset control to be reassigned to an
address other than zero.
CHARACTER GENERATORS
The 1K video RAM drives a 2K ROM character generator providing the
standard ASCII character set with some additions, 128 characters in all.
There is a second 2K ROM socket for an on-board graphics package which is
software selectable. Gives another 128 characters.
The PCB is, of course, of industrial standard, through hole plated, masked
and screen printed.
DOCUMENTATION
Full construction article is provided for those who buy a kit and an extensive
software manual is provided for the monitor and Basic.
Nett VAT Total
Nascom-2 in kit form .....00... 295.00 23.60 318.60
° RING FOR A DELIVERY DATE
NASCOM NAS-SYS I MONITOR
For use with the Nascom 2 and its new keyboard, a completely new monitor
has been designed. It incorporates all the features of the Nasbug 2K Monitor
(T4) with many additional functions.
The most obvious enhancement is the use of a blinking non-destructive
cursor with on-screen editing facilities using the left, right, up and down
arrow keys. Aroutine is provided which gives the user a pointer to an edited
line of text, input via the screen and keyboard, allowing user programs to
exploit this powerful feature.
The method of calling routines has been modified and rationalised so that,
in most cases, users need only a two byte RST operation. It also allows the
monitor to be changéd and improved at a later date without needing to re-
allocate jump addresses.
Although primarily designed for use with the new keyboard, all features can
be used with the currant Nascom | keyboard by using combinations of keys.
As with Nasbug T4, ASCH terminals are fully supported via the serial
interface and can be switched on and off using the X and N commands.
Users can add their own I/O drivers via the Nas-sys I/O driver table to
support other devices.
Execute at FFA (to start Basic etc.)
set keyboard options
Load from tape
Modify store
— execute at FFD
(warm start for Basic)
The 22 commands supported are: x 7] deel ala
A — hexadecimal Arithmetic Q — (Query) input from port
B — set Breakpoint R — Read tape
C — Copy — S — Single step
E — puecute T — Tabulate
— Generate U — acti i
H — Operate as half duplex ASCIl termina y _ eee” i alg
| Intelligent copy W — write tape
J x
K 4
[E
M
ele) Wl
Following the success of its NASCOM-1 Microcomputer
— set external device options
TAICRODIGITA
A total of 42 user accessible RST operations are provided including
character input/output, system reset, relative sub-routine call,
input a line, position cursor etc.
NASCOM 2 EXPANDED KEYBOARD
Ten new keys have been added, as follows:
(a) Graphics — when used in conjunction with Nas-sys simplifies
generation of graphics characters from the keyboara.
(b) contro! — to generate control characters.
(c) — cursor control keys for use with Nas-sys.
(qd) LF to allow input of additional useful characters.
CH, LF, CH to allow.
(e) Shift — an additional shift key has been added on the left-hand side of
keyboard — particularly useful for typing in Basic or other high level
language programs.
As with the currant Nascom keyboard, the switch mechanisms are contact-
less, high reliability professional standard units for long trouble free life.
NASCOM 8K BASIC
Nascom 8K Basic is based on the Microsoft 8K Basic which has become the
de facto industry standard. It, therefore, offars a high degree of compatibility
with other systems, and programs published in magazines andbooks should
run under Nascom 8K Basic with little or no modification.
It offers a full range of string handling and arithmetic functions and handles
numbers inthe range 1.70141E38 to 2.9387E-38. it also supports use of the
PIO using the INP, OUT and WAIT commands.
NASCOM BASIC operates with Nasbug T2, Nasbug T4 andthe new Nas-Sys
maT It is supplied as either 8 x 2708 EPROMS or 1 x MK 3600 64K bit
The most obvious feature, when used with Nas-Sys, are the extensive line
editing features which make data or program entry and modification very
simple — allowing insertion, modification or deletion of single or multiple
characters.
In order to allow for flexible screen formatting, a cursor positioningcommand
(SCREEN), and aclear screen command (CLS) have been incorporated. Also,
by setting parameters, input can be undertaken on a character by character
basis so that forms can be simply created and edited on the screen.
Backspace and delete functions are retained, and characters are input on a
character by character basis when supporting a terminal on the serial
interface. The width of a printed line can be set by the WIDTH command, and
the serial interface turned on and off under program control so that a printer
can be attached and supported with no additional software or interface
hardware.
Normally the LIST command scrolls five lines at a time, then waits for a
character to be typed before scrolling another five lines (or aborting if escape
is typed). However, the number of lines scrolled can be set by the LINES
command to any number allowing a complete LIST to be generated on a
printer without pausing, or to scroll through a program ata faster (or slower)
rate.
Program saving and loading uses the monitor's tape readand write routines,
providing block checking and information about the success and progress of
the operationonthe screen. Program file names are displayed whenreadtoo.
Arrays can beread or written to tape, andthe Nascom routines incorporatea
16 bit sumcheck to verify the accuracy of data read.
System modifications and machine code routines have been made easier by
the inclusion of the routines DEEK andDOKE, routines which read or write 16
bit integers.
The Nascom graphics option is supported by the routines SET (X, Y) and
RESET (X, Y) — which tight up or erase point X, Y ona 96 x 48 point grid, and
the function POINT (X, Y) which returns the vaiue 1 if the point X, Yistit up, or
zero if it is not.
The comprehensive modifications and extensions to the original Basic
provide both the Nascom 1 and the Nascom 2 with probably the most
powerful 8K Basic available on any personal computer system today.
8K Basic Summary
Commands:
NEW LIST CONT MINOTOR RUN
CLEAR NULL SCREEN LINES WIDTH
Program Statements:
DEF DOKE 1F.,. THEN FOR
DIM END .ON,..GOTO LET NEXT
GOSUB GOTO RETURN OUT POKE
REM ON...GOSUB STOP
WAIT SET
RESET
PRINT DATA INPUT READ CLS RESTORE
Operators: +
= a *« /
A~ ‘N - NOT AND
> = = <> <
Functions:
ABS ATN LOG SIN PEEK
INP INT SGN TAN SPC
POS RND USRn cos DEEK
SOR TRAB EXP FRE POINT
ASC CHRY FRE STRS RIGHTS
LEFTS LEN MIDS VAL
Cassette Input/Output Functions:
CSAVE (Array or program) CLOAD (Array or program)
PERSONAL COMPUTER WORLD BENCHMARK TESTS
APPLE I RM. 3802
INTEGER B NASCOM 2 8K ZAPPLE PET
BM 1 1.5 Ww 1.4 7
BM 2 3.2 5.4 6.5 9.9
BM 3 7.3 11.1 13.2 18.4
BM 4 7.2 11.6 13.9 20.4
BM 5 8.9 12.6 15.0 21.7
BM 6 18.6 19.3 22.3 32.5
BM7 28.2 27.6 31.6 50.9
BM 8 5.2 6.2 12.3
A?
A8
“aa
Rockwell
2/\ICRODIGITAL
The Head-Start
in Computers
AIM 65 Technical Overview
THERMAL PRINTER
Most desired feature on low-cost
microcomputer sysiems
® Wide 20-cotumn printout
® Versatile 5 x 7 dot matrix format
* Comptete 64-character ASCII alphanumeric
format
© Fast t20 Itnes per minute
® Quiet thermal operation
© Proven reliability
FULL-SIZE ALPHANUMERIC KEYBDARD
Provides compatibility with system terminals .
Standard 54 key. termsnal-style {ayout
26 alphabetic characters
10 numeric characters
22 special characters
9 control functions
3 user-defined functions
TRUE ALPHANUMERIC DISPLAY
Provides legible and tengthy display
*® 20 characters wide
© t6-segment characters
@ High contrast monolithic characters
* Comptete 64-character ASCII alphanumenc
format
PROVEN A6500 MICROCOMPUTER
SYSTEM DEVICES
Reliable, high performance NMOS
technology -
@ A6S02 Centrat Processing Unit (CPU),
operating at 1 MHz.
Has 65K address capabillty, 13 addressing
modes and true index capability. Simple. but
Powerful 56 instructions.
© Read/Write Memory, using R2114 Static RAM
devices. Avaitable in 1K byte and 4K byte
versions.
®@ 8K Monitor Program Memory, using A2332
Static ROM devices. Has sockets to accept
additional 2332 ROM or 2532 PROM devices, to
expand on-board Program Memory up to 20K
bytes.
@ A6532 RAM-Input/Output- Timer (RIOT)
combination device. Multipurpose circuit for
AIM 65 Monitor functions.
© Two A6522 Versatile Interface Adapter (VIA)
devices, which support AIM 65 and user
functions. Each VIA has two parallel and one
sertat 8-bit, bidirectional (/O ports, two 2-bit
peripheral handshake control lines and two.
fully-programmable 16-bit interval timer/event
counters,
BUILT-IN EXPANSION CAPABILITY
¢ 44-Pin Application Connector for peripheral
add-ons
@ 44-Pin Expansion Connector has full system
bus
@ Both connectors are KIM-1 compatible
TTY AND AUDIO CASSETTE INTERFACES
Standard intertace to low-cost peripherals
@ 20 ma. current loop TTY interface
© Intertace for two audio cassette recorders
© Two audio cassette formats: ASCII KIM-1
compatible and binary. blocked file assembier
compatible
ROM-RESIDENT ADVANCED INTERACTIVE
MONITOR
Advanced features found only on larger
systems .
Monitor-generated prompts
Single keystroke commands
Address Independent data entry
Debug aids
Error messages
Option and user interface tinkage
eoeeee
AIM — 65 with 1K RAM 249.50
AIM — 65 with 4K RAM 315.00
8K Basic in ROM
4K Assembler in ROM
ADVANCED INTERFACE MONITOR
COMMANDS
Major Function Entry
(RESET Button)—Enter and initialize Monitor
ESC—Re-enter Monitor
—Enter and initialize Text Editor
—fe-enter Text Editor
—Enter Assembler
—Enter and initialize BASIC Interpreter
—Re-enter BASIC interpreter
OAnazam
Instruction Entry and Disassembly
|) —Enter mnemonic instruction entry mode
K —Disassemble memory
Display/Alier Registers and Memory
* —Alter Program Counter to (address)
—Alter Accumulator to (byte)
—Alter X Register to (byte)
—Alter Y Register to (byte}
Alter Processor Status to (byte)
—Alter Stack Pointer to (byte)
—Display all registers
—Displays four memory locations, starting
at (address)
(SPACE)—Display next four memory locations
/ —Alter current memory tocation
ZDNV<x>
Manipulate Breakpoints
# = —Clear all breakpoints
4 —Toggle breakpoint enable on/off
B —Set one to four breakpoint addresses
? —Display breakpoint addresses
Control instruction/Trace
G —Execute user's program
Z —Toggie instruction trace mode on/oft
V —Toggle register trace mode on/off
H —Trace Program Counter history
Control Peripheral Devices
& —Load object code into memory from
peripheral i/O device
D —Dump object code to peripheral /O
device
1 —Toggle Tape 1 controt on/off
2 —Toggle Tape 2 control on/off
3.) —Verify tape checksum
CTAL PRINT—Toggie Printer on/oft
LF —Line Feed
PRINT—Print Display contents
Call User-Defined Functions
Ft —Call User Function 1
F2 —Call User Function 2
F3 —Call User Function 3
Text Editor Commands
AR —Read tines into text buffer trom peripheral
VO device
| —Insert line into text buffer from Keyboard
K —Delete current line of text
{SPACE)—Display current line of text
—List lines of text to peripheral I/O device
—Move up one line
—Move down one line
—Go to top line of text
—Go to bottom line of text
—Find character string
=-~Change character string
—Ouit Text Editor, return to Monitor
LOW COST PLUG-IN ROM OPTIONS
@ 4K Assembler — symbolic, two-pass
*@ 8K BASIC Interpreter
POWER SUPPLY SPECIFICATIONS
e+ 5 VDC + 5% regulated @ 2.0 amps {max)
* +24 VDC + 15% unregulated @ 2.5 amps (peak)
0.5 amps (average)
oone+ocr
Nett VAT Total
19.96 269.46
25.20 340.20
70.00 5.60 75.60
59.50 4.76 64.26
Rockwell's AIM 65 Advanced Interactive Microcomputer can get you Into the exciting world of
microcomputers a tot easier and at a lower cost than you may have thought possible, And you'll be
working with the 6500 family, the advanced state-of-the-art NMOS system that’s an
everincreasing favorite for new Commercial and hobbyist applications
As a learning aid, AIM 65 gives you an assembled, versatile microcomputer system with a
fullsize keyboard, 20-character disolay and, uniquely, a thermal printer. An on-board Advanced
Interactive Monitor program provides extensive control and program development functions. And
our AIM 65 User's Manual will hetp you along each step of the way.
You'll master fundamentals rapidly. Then youll appreciate the tact that unlike the computer
‘tloys” on the market, AIM 65 offers flexibiity and expandability you would expect to find in a
sophisticated microcomputer development system.
THERMAL PAINTER GIVES YOU HARD COPY — FAST AND QUIET.
AIM 65's 20-cotumn Thermal Printer prints on low-cost, thermal roll paper at a fast 120 lines per
mihute. It produces all of the standard 64 ASCII characters with a crisp-printing five-by-seven dot
matrix. AIM 65's on-board printer is a unique feature for a low-cost computer.
EXTENDED ALPHANUMERIC DISPLAY IS SUILT FOR UNDERSTANDING, NOT
DECIPHERING.
AIM 65 comes with a 20-character true Alphanumeric Display. Information is displayed with
bright, magnified 16-segment font monolithic characters. It's both unambiguous and easily
readable.
FULL-SIZE KEYBOARD IS DESIGNED FOR HUMANS, NOT ELVES.
AIM 65's terminal-style keyboard frees you from the hassies of fumbling around with a tiny
calculator-type keypad. And iis 54 keys provide 70 different alphabetic, numeric, control and
spectal functions.
ON-BOARD ADVANCED INTERACTIVE MONITOR GETS YOUR PROGRAMS
UP AND RUNNING.
The ROM-resident AIM 65 Advanced Interactive Monitor Program provides a comprehensive set
of easy-to-use, single-keystroke commands for debugging your programs, and offers features
Normally available only tn larger, expensive microcomputer development systems. And with the
AIM 65 Monitor, there's no guesswork involved, the Monitor gives a self-explanatory prompt when
it'needs information and it will generate a meaningful error message if an error has occurred,
The AIM 65 Monitor includes commands to
Enter and edit programs directly — no “opcode” memorization
List programs on Printer or TTY
Display/alter registers and memory
Set breakpoénts, trace and debug program execution
Control the Thermal Printer
Transter information to/from attached Cassette Recorders or TTY
Execute programs in on-board or external RAM, ROM or PROM memory
Interface the optional AIM 65 Assembler and BASIC interpreter
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AIM 65'S ADVANCED R6500 NMOS ARCHITECTURE.
The R6502 Central Processing Unit is the heart of the AIM65, It provides demonstrated speed and
simplicity, plus 65K addressability and the power of a 56-command, minicomputer-iike
Instruction set.
The A6S5S32 AAM-Input/Output-Timer (RIOT) combination device is used by the AIM 65
Monitor for scratchpad memory and Keyboard operations,
Two R6522 Versatile Interface Adapter (VIA) devices are provided. One device supports AIM
65's Thermal Printer and the TTY and Cassette Intertaces, the other supports two user-dedicated
8-line I/O ports, ptus an 8-bit serial I/O port and access to two 16-bit interval timer/event counters,
on the module's Application Connector.
AIM 65 comes with two A2332 4K Read Only Memory (ROM) devices installed. These hold the
Advanced Intertace Monitor program. Spare sockets allow the user to expand on-board ROM up
to 20K bytes. These sockets will accept user programs on R2332 ROMs or comy tible PROMs. or
can be used to install the optional AIM 65 Assembler and BASIC Interpreter ROM devices.
On-Board Read/Write RAM me™ry is available in 1K-byte and 4K-byte configurations.
AtM 65 HAS EXPANSION BUILT IN.
And to allow AIM 65 to grow the way you want it to. we've provided an Application Connector and
an Expansion Connector. The Application Connector permits you to plug on a TTY (20 ma.
current loop, and one or two standard audio cassette recorders. It also has the pinouts for the
VIA'’s General-Purpose I/O ports. The Expansion Connector extends AIM 65’s system bus —
address, data and control — out to additional memory, or anything else you might attach.
And, BASIC high-level language programming is a built-in option.
A professional MPU card - designed as a general purpose industrial
controller based on the 6502 MPU, this card is complemented by a
matching Eurocard hex keyboard and CUTS standard cassette interface, to
create the new ACORN MICROCOMPUTER.
This compact stand-alone micro-computer is based on standard Eurocard
modules, and employs the highly popular 6502 MPU fas used in Apple, Pet,
Kim, etc}. Throughout, the design philosophy has been to provide full
expandability, versatility and economy. Take a look at the full specification,
and see how Acorn meets your requirements.
Acorn technical specification
The Acorn consists of two single Eurocards:
1. MPU card: 6502 microprocessor; 512 x 8 ACORN monitor; 1K x 8 RAM;
16-way I/O with 128 bytes of RAM; 1 MHz crystal; 5 Vregulator, sockets for
2K EPROM and second RAM I/O chip.
2. Keyboard card; 25 click-keys (16 hex, 9 control); 8 digit, 7 segment
display CUTS standard crystal controlled tape interface circuitry.
Compect, easy to use Acorn Monitor includes the following features:
@ System program
@ Set of sub-routines for use in programming
@ Powerful de-bugging facility displays all internal registers
@ Tape load and store routines
Science of Cambridge
o Sy
MK 14 KIT
This is probably the cheapest complete home computer, the kit costing less
than the retail price of the chips included in it. The specification is as
follows:
1 Hexadecimal keyboard.
2 8 digit LED display.
3 512 x 8 PROM, containing monitor program and Interface instructions.
4 256 Bytes of RAM.
5 4 MHz crystal.
6 5 Voit stabiliser.
7 Single 6 Volt power supply requirement.
8 Space avallable for extra RAM and RAM I/O.
Pulte CE NEWBEAR 77/68
This is a new concept for low cost computing. Each of these bags contain all
the parts necessary to build a vital part of a microcomputer system. Each
part is backed with the support necessary for such a complex project.
Bear Bag No 1 77-68 P.C.8., Components & Edge Connector.
This contains all the parts which fit on this low cost start to a large 6800
microcomputer system.
Nett VAT Total
45.00 3.60 48.60
Bear Bag No 2 77-68 LED's and Switches
This kit contains high lumance 0.2” LED’S and high reliability gold plated
subminiature toggle switches suitable for low voltage low current contacts,
to match Bearbag No 1.
14.95 1.20 16.15
Bear Bag No 4 77-68 5 u Rack Backplane
This card frame is not the cheapest way of mounting 77-68 p.c.b.'s but it is
the recommended one. (The lowest cost alternative is to use a wooden box
and plastic double glazing channel for guides).
27.70 2.22 29.92
Bear Bag No 5 77-68 4 K RAM P.C.B. and Components
This is the vital element for any computer. This design is fully buffered and
address decoded. The 4K block can be positioned anywhere within the 64K
memory allowable.
75.00 6.00 81.00
Bear Bag No 6 77-68 Mon 1 P.C.B. and Components
This board can support two V24/RS232C interfaces or 20 MAcurrent loop
(only one supplied) and a method of “bootstrapping” a kilo byte of operating
system into protected memory. Alisting of an operating system Is supplied
and Kansas City cassette or Paper tape !s available. Beware to load the
operating system a Kansas City cassette interface If required (see Bear Bag
No 10} or a terminal with a paper tape reader.
50.70 4.06 54.76
Bear Bag No 9 Petitevid V.D.U. Kit Mk2
All the electronics for a VDU ona single 8” x 4" card! The latest Thompson
CSF Super Chip does all the hard work and the result is a full scrolling VDU
64ch by 16 lines with full cursor control, software “home” and software of
hardware clear screen. the interface is V24/RS232C switchable between
110 baud, 300 baud and 1200 baud.
85.00 6.80 91.80
Bear Bag No 10 Kansas City Cassette Interface.
This interface solves your bulk storage problem immediately. The method of
use is quite simple. It sits in the V24/RS232C interface between your
computer and VDU or Teletype and is switched in and out as appropriate
when information is recorded from the computer or played back into it.
Nett VAT Total
18.95 1.52 20.47
Acom — with real expandability
The standard Acorn is fully expandable to 65K of memory, and the Acorn bus
is available on the 64-way edge-connector. Whether you're a beginner in
the field, an ambitious home computer buff, a development engineer, a
teacher or abusinessman, the Acorn and its family of modules will provide a
practical solution in virtually every situation.
Acorn Operating Manual
With Acorn, you'll recelve an operating manual that covers computing in
full, from first principles of binary arithmetic, to efficient hex programming
with the 6502 instruction set. The manual also includes a listing of the
monitor programs and the instruction set, and other useful tabulations; plus
a selection of 12 interesting and educative program samples.
Acorn MPU card with 1K RAM and keyboard card with cassette interface In
kit form, with assembly instructions. Nett VAT Total
65.00 5.20 70.26
Ready built.... : eer .... 75,00 6.00 81.00
The kit is based on the Natlonal Semi-conductors SC/MP2 microprocessor
and programs are entered in machine code through tne nexacecimai
keyboard, the results showing on the calculator type display. Each kit is
supplied with an Operations Manual which contains operational
instructions, examples for training applications, and numerous programs
including math routines, timing general purpose sequencing, games, etc.
VAT Total
Sclence of Cambridge Mk 14 kit........ F : 43.15
Socket Set : ‘ 3.89
256 x 4 extra RAM (2 required ......... : 3 3.19
INS 8164 RAM I/O eR es : ; 8.82
Power Supply ........... ; : 4 5.75
Cassette Interface...... -96 -f 6.43
PROM Blower " 10.75
Bear Bag No 12 77-68 V.D.U. Kit
This is a Direct memory accessed type of Visual Display Unit which gives a
very fast writing speed. Its format is 40ch by 24 lines e.g. Teletext. Its output
is composite video and it also has a keyboard interface which expects
parallel 7 bit ASCII and strobe.
69.50 5.66 75.06
Sear Bag No 13 77-68 Mon 2 Kit.
This board can support ‘“MIKBUG” (with a hardware single step). or
“SWATBUG" ona 2708 Eprom. The V24/RS232C ports can be via one of
the two 6821 PIA‘s or the ACIA port.
64.16 5.13 69.23
Bear Bag No 14 2708 Prom Programmer Kit (6B00)
This is a low cost programmer which contains its own power supply and
interfaces to a 6820 PIA. A novel approach has been adopted by supplying
the necessary software in a 2708 and a short copying program to place it
RAM. A low insertion force socket is provided.
35.00 2.80 37.80
Bear Bag No 15 Promverter. Mikbug to 2708
Ail the people who have suffered MIKBUG now have the chance to write
their own operating system, plug it in the 2708/6830 converter and so
replace (at last) MIKBUG.
8.50 0.68 9.18
Bear Bag No 16 77-68 Eprom Board (ROMA)
This board holds up to 8K bytes of 2708 Eproms or 16K bytes of Intel 2716.
This bag does not contain the EPROMS.
29.50 2.36 31.86
Bear Bag No 17 77-68 Interface Board (P10)
This is a utility board which helos make 77-68 the most complete hobbvist
system available, supplying a 6840 timer and enough 68201/O portstokeep
your perlpherals busy.
45.00 3.60 48.60
Bear Bag No 18 Cottis Blandford Cassette Interface.
This high speed cuts cassette interface was designed to be not only lowcost
but also Kansas City compatible, very few adjustments e.g. one! and up to
2400 baud or perhaps even 5000 baud.
17.25 1.38 18.63
Bear Bag No 21 Lower Case for Petitevid
Asmall modification to your “Petitevid VDU kit can add lower case letters.
10.50 0.84 11,34
Mircroprocessors: from chips to systems.
R. Zaks — £7.95
Microprocessor interfacing techniques.
Microprocessor interfacing techniques.
R. Zaks — £7.95
Practical solid circuit design.
Olesky — £5.20
555 Timer applications source book. — £0.00
Understanding solid state electronics.
Texas instruments — £2.40
Modern operational circuit design.
Smith — £18.60
Microprocessor systems design.
Klingman — £14.00
Microcomputer design.
Martin — £12.00
Designing with TTL integrated circuits.
Texas instruments — £24.80
Fundamentals and applications of digital logic
circuits — S. Libes — £6.36
Analysis and design of digital circults.
P. Chirlian — £16.40
Linear IC principles, experiments, and projects
E. M. Noll — £7.16
Semiconductor circuit elements.
T. Towers and S. Libes — £6.56
TTL cookbook.
D. Lancaster — £7.50
CMOS cookbook.
D. Lancaster — £7.96
RTL cookbook.
D. Lancaster — £5.15
Active Filter cookbook.
D. Lancaster — £11.96
T. V. Typewriter cookbook.
D. Lancaster — £7.50
Cheap Video cookbook.
D. Lancaster — £5.10
Microcomputer problem solving using
“PASCAL — K.L. Bowles — £7.84
“PASCAL User Manual and-Report.
°* Jensen and Wirth — £6. 62
‘ An introduction to programming and problem
solving with PASCAL.. Schneider, Weingart
and Perlman — £10.36
Programming in PASCAL.
P| Grogono — £7.50
PASCAL — An introduction to methodical
.programming — W. Findlay and
OD. A. Watt — T.B.A.
Best of BYTE vol. | — Helmers et al — £8.96
Best of Creative Computing vol. |
AHL et al — £6.95
Best of Creative Computing vol. 2
AHL et al — £6.95
Dr. Dobbs Journal of computer Calisthenics
and Orthodonita vol. |.
J.C. Warren — £10.00
Scelbi-Byte Primer,
Helmers et al — £9.95
The Best of Micro.
Tripp et al — £6.95
The First West Coast Computer Faire
proceedings — J. C. Warren — £9:56
The Second West Coast Computer Faire
proceedings — J. C. Warren — £9-56
BOORWOR
Program Design.
W. Liffic — £4.80
Simulation — B. W. Liftic — £4.80
Basex — P. Warne — £6.40
The BYTE book of computer music,
C. P. Morgan — £8.00
Superwumpus — J. Emmerichs — £4.80
Ciarcia’s Circuit Cellar.
S. Ciarcia — £6.40
Bar Code Loader — K. Budnick — £1.60
Tiny Assembler 6800 v3.1.
J. Emmerichs — £7.20
Tracer: A 6800 debugging program.
J. Hemenway — £4.80
MONDEB: An advanced 6800 Monitor-
debugger — D. Peters — £4.00
RA68O0ML: An M6800 Relocatable Macro-
assembler — J. Hemenway — £20.00
LINK 68: An M6800 Linking loader.
J. Hemenway et al — £6.40
The 8080A Bugbook- Microcomputer,
interfacing and programming.
P. R. Rony et al — £7.95
8080 machine language programming for
beginners — R. Santore — £65.10
Scelbi "8080" software gourmet guide and
cookbook — Scelbi computer consulting —
£7.95
A step by step introduction to 8080
microprocessor systems.
D. L. Cohn and J. L. Metsa — £5.70
8080/8086 Software design.
C. A. Titus, P. R. Rony et al — £7.50
8080 Programming for logic design.
A. Osborne — £5,95
Practical microcomputer programming:
The Intel 8080..
W. J. Weller et al — £17.56
Scelbi’s 8080 standard monitor £9.95
Scelbi's 8080 standard editor £9.95
Scelbl’s 8080 standard assembler £16.95
Sceibi computerconsultants.
‘8080 Assembley language programming.
L. Leventhal — £7.95
An
‘8080 Assembly language Pro Laetning:
L. Leventhal —£7.95
An Editor/Assembler system for 8080/8085
based computers — W. J. Weller — £11.96
Scelbi 8080 Galaxy game.
Scelbi-computer consultants — £7.95
F Programmers pocket guide. _
icelbi.computer consultants-— £1.95 =
8080 Hex code card — Scelbi — £1.96
8080 Octal code card — Scelbi — £1,96
2-80 instruction handbook — Scelbi — £3.95
Practical microcomputer programming:
the Z80 — W. J. Weller — £23.96
Sargon 280 Chess Program.
D. and K. Spracklten — £9.50
The 280 microcomputer handbook.
W. Barden — £6.95
A-80 Programming for logic design.
A. Osborne — £5.95
Z-80 Programming manual.
Mostek — £4.50
Nascom-1 Hardware notes — £1.50
Nascom-1 Programming manual — £1.50
‘Nascom-1 Seminar notes — £1.50
Sorcerer Technical manual — £T.B.A.
Sorcerer Technical manual — £8.95
Practical microcomputer programming: the
M6800 — W. J. Weller et al — £17.56
Scelbi 6800 Gourmet guide.
Scelbi computer consultants — £7.95
Programming the 6800 microprocessor.
Bob Southern — £8.00
6800 Assembly language programming.
L. Leventhal — £7.95
Using the 6800 microprocessor.
E. Poe — £6.25
6800 Programming for logic design.
A. Osborne — £6.30
77-68 Design manual — T. Moore — £7.50
APL — an interactive approach.
Gilman and rose — £9.50
Structured Programming in APL.
Geller and Freedman — £7.96
APL — A short course — Pakin et al — £7.35
APL — The language and it's usage.
Polivka et al — £15.05
Microprogrammed APL implementation.
R. Zaks — £14.76
Fortran fundamentals — A short course.
J. Steingraber — £2.95
FORTRAN Programming — £6.75
FORTRAN workbook — £4.76
Instructor's manual for FORTRAN
programming — £4.95
FORTRAN programming — £6.95
A guide to SC/MP programming.
Drury £4.00
A Guide to KITBUG — Drury — £1.00
Artist and computer — A. Leavit — £3.96
Basic computer games — D. H. Ahi — £5.60
Game playing with BASIC.
D. Spencer — £5.56
How to build a computer controlled robot.
T. Loofborrow — £6.36
Starship simulation — R. Garrett — £5.10
Game playing with computers.
D. Spencer — £13.56
57 Practical programs and games in BASIC.
K. Tracton — £6.36
Chess and computers — D. Levy — £7.16
1975 U.S. Computer chess championship.
D. Levy — £4.75
1976 U.S. ae chess championship.
D. Levy — £4.7
Chess skill in man and machine.
P. Frey ed — £11.84
Some common Basic programs.
A. Osborne — £6.30
‘Introduction to artificial intelligence.
Jackson — £14.80
How to profit from.your personal computer.
T. G. Lewis — £6.36
Build your own yeh robot.
0. L. Heiserman 4.7
Computer programs ae Sa
Beech etal — £2.55
The mind appliance: home computer
applications — T. G. Lewis — £6.36
Robots on your doorstep.
N. Winkiess and t Browning — £5.56
Artificial intelligence.
P.H. Winston — £T2.00
Computer power and human reason.
J. Weizenbaum — £4.76
The thinking computer: mind inside matter.
8B. Raphael — £5.56
Data books.
TTL Data book, 2nd edition £5.00
TTL Data book supplement £1.00
Semiconductor memory Data book £2.40
Power semiconductor handbook — £6.00
Transistor and diode Data book — £6.80
Optoelectronics Data book, 5th ed — £2.80
Bipolar microcomputer components
Data book — £2.40
Linear Control circuits Data book — 2.40
Interface Data book — £2.80
MOS memory Data book — £2.80
Scientific Research-Basic library.
A complete reference library of BASIC programs
in 8 volumes:
1—Bookkeeping. Games, Pictures — £17.50
2—Maths/engineering, plotting/statistics,
Basic statements defined — £17.50
3— Advanced business, billing, inventory,
investments, payroll — £26.95
4—General purpose — £7.95
5—E€xperimenters programs — £7.95
6—Mini-ledger — £32.50
7—Professional programs — £29.95
8—Homeowners programs — £T.B.A.
The Systems Analyst.
J. W. Attwood — £6.60
Computers for the Physician’s office.
Zimmerman et al — £15.40
Accounts Payable/Accounts receivable £9.95
General Ledger £9.95
Payroll with cost accounting £12.00
A. Osborne et al.
Take my computer please!
S. Ciarcia — £ T.B.A.
Computer Rage.
Creative computing — £6.95
Charging for computer services.
D. Bernard et al — £8.00
The technology of computer music.
M. Mathews — £12.80
A Dictionary of microcomputing.
P. Burton — £10.00
PCC reterence book — PCC £4.95
Microprocessor lexicon — £2.00
Computer Dictionary — £5.46
Computer Dictionary and Handbook.
Sippl et al — £11.99
Computer Dictionary (2nd edition.)
Sipp] — £6.95
Microcomputers at a glance.
D. Spencer — £6.45
Computer Data directory — £3.98
Microprocessor encyclopedia. vol 2.
Bit-slice machines — R. Zaks — £7.45
The microcomputer handbook.
Sipp! — £15.96
How you can learn to live with computers.
H. Kleinberg. — £7.16
Getting involved with your own computer.
L. Solomon and S. Veit. — £4.76
Microcomputer primer.
M, Waite and M. Pardee — £6.35
Small computer systems handbook.
S. Libes. £6.75
Your home computer.
J. White - £5.10
Understanding microcomputers and smail
computer systems.
N. Wadsworth — £7.95
Computer Science: projects and study
problems.
Forsythe et al — £7.80
Home computer revolution.
T. Nelson — £2.75
An introduction to personal and busines
computing.
R. Zaks — £4.95
* BOORAWORM
How to buy and use minicomputers and
microcomputers.
W. Barden jr — £7.50
Hobby computers are here.
"73" — £3.95
Introduction to microcomputers vol. 1.
A. Osborne — £5.95
The new hobby computers.
"73" — £3.95
Introduction to computer programming.
Crawford and Copp — £3.84
Microprocessor basics.
M. S. Eiphick — £6.60
Computer Lib.
T. Nelson — £5.95
Getting acquainted with micros.
L. E. Frenzel — £6.95
Fundamentals of Digital Computers.
D. Spencer — £7.50
Finite State fantasies.
Motrin Publishers — £2.00
Computer Science: a first course
Forsyteh et al — £14.60
Consumers guide to personal and home
computing.
S. Freiberg et al — £4.80
About Computers.
£6.95
Home computers: a beginners
glossary and guide.
M. Miller and C. Sipp! — £4.95
Computers and programming guide for
engineers.
D. Spencer — £9.45
Microprocessors: new directions for designers
E. A. Torrero — £6.60
Home computers 2°°10 questions/answers
vol. 1 Hardware.
R. Didday — £5.70
Home computers 2*°10 questions/answers
vol 2. software. — R. Didday — £4.95
Understanding computers.
P. Churlian — £6.51
‘Be a computer literate!
M. J. Bell and S. Charp — £3.16
Introduction to Microprocessors.
D. Aspinall et al — £5.95
Microcomputers — The mini-microrevolution.
A. Simpson — £9.95
Introduction to microprocessors and
computing.
E. F. Scott — £2.30
Iilustrating Basic — a simple programming
language — D. alcock — £2.25
Basic BASIC: an introduction to computer
programming in the BASIC language — £6.50
and Advanced BASIC: applications and
problems — £6.00 both by J. S. Coan.
A guided tour of computer programming in
BASIC — T. A. Dwyer and M. S. Kaufman —
£4.16
Computer resource book-Algebra.
T. A. Dwyer and M. Critchfield — £4.16
BASIC with business applications
R. W. Lott — £8.40
BASIC and the personal computer.
T. A. Dwyer and M. Critchfield — £10.36
Basic: a hands on method
H. Peckham — £6.36
PLEASE SEND ME:
Instant Basic
G. R. Brown — £7.20
Introduction to BASIC.
J. Morton — £6.50
BASIC — a unit for secondary schools.
D. Spencer — £4.45
Teachers manual for BASIC.
£6.45
Accent on BASIC — £4.95
Beginning BASIC — P. Chirlian — £7.12
A Quick look at BASIC — £4.45
Sixty challenging problems with BASIC
solutions — £5.95
Fun with computers and BASIC
D. Spencer — £5.45
My computer likes me... when | speak in
BASIC — D. H. Ahl — £1.65
BASIC programming — £6.95
Programming a microcomputer: 6502
C. C. Foster — £7.96
Microcomputer programming: 6502.
R. Zaks — £7.95
6502 Applications book.
R. Zaks — £10.25
6502 Hardware manual — £7.50
6502 Software manua — £7.50
The first book of KIM.
J. Butterfield et al — £7.16
APPLE Il Operators manual — £5.50
APPLE II Integer BASIC manual
J. Raskin — £4.00
APPLE i! APPLESOFT eatended BASIC
manual — J. Raskin — £4.00
TIS Workbooks for the Commodore PET 2001
TIS — £3.00 each
1—Getting started with your PET
2—PET string and array handling.
3—PET Graphics
4—PET cassette I/o
5—PET miscellaneous
6—PET interfacing techniques.
The art of computer programming 1, 2, 3
by D. K. Knuth
Volume 1 Fundamental Algorithms.
D. E. Knuth — £9.50
Volume,2 Seminumerical algorithms.
D. E. Knuth — £17.56
Volume 3 Searching and sorting.
D. E. Knuth — £17.56
Top-down structured programming
techniques — C. L. McGowan
and J. R. Kelly — £12.76
Software Tools.
Kernighan and Plauger — £7.20
Programming Proverbs — H. Ledgard — £5.56
Software design for microprocessors.
J. G. Wester and W. D. Simpson — £10.36
A collection of programming problems and
techniques, — H. A. Maurer and
M. R. Williams — £11.16
Problems for computer solution.
S. Rogowski — £7.96
The design of well-structured and correct
programs — S. ALagic
and M. A. Arbib — £10.24
Assembly level programming for small
computers — W. J. Weller — £12.76
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CHROMA CHIME DOOR-CHIME KIT CHiP SHOP
This is one of our favourite products because of the way it takes the mystique out
of computers. A Texas Instruments TMS 1000 microprocessor is A Selection from our range of semiconductor
pre-programmed with 24 popular tunes. It is possible to select the tune of the day, devices:
how loud it plays, the speed it plays at and the envelope decay rate of the notes
A second bell-push can be added for the back door, which will play a different Nett VAT Total
tune and an additional loudspeaker can be used. 280 CPU ..............15.00 1.20 16.20
The excellent handbook contains comprehensive building instructions and SC/MP IICPU......... 9.00 0.72 9.72
technical details. Anyone reasonably competent with a soldering iron can 8080 CPU....... Roo oc 9.00 0.72 9.72
complete construction in less than two hours. 6800 CPU van- cre coon 8.58 0.69 9.27
Nett VAT Total 6502 CPU... 2:5. 14.93 1.19 16.12
hime AOOrtEHInS Wit... «ce « mesmsaner GSO2'CRU oo. ce. ca. ee 10.00 0.80 10.80
Chroma Chime door-chime kit 8.84 1.11 9.95 6850 ACIA ............ 7.20 0.58 7.78
OO SS 6402 UART............ 5.50 044 5.94
SINCLAIR PDM 35 DIGITAL MULTIMETER 3881 PIO.............. 8.00 0.64 8.64
3882 CliG. eee ee 8.00 064 8.64
A 3", digit digital multimeter at an analogue price, the PDM 35 can be used for a wide 5204 UVEPROM....... 7.00 0.56 7.56
variety of electrical and electronics testing, as the specification shows. 2708 UVE PROM ...... 10.00 0.80 10.80
D.C. Volts: = Imv - 1000v (%+1 count) 10 m S01 input 8154 RAM I/O........ 8.17 065 8.82
A.C. Volts: — 1v - 500v 40 HZ - 5KHz (1%+t2 counts) 2111 RAM ............ 2.95 0.24 3.19
D.C. Current: 1 mA - 200 mA (1%+1 count) 1103 DRAM........... 1.10 0.09 1.19
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96364 VDU ........... 11.75 0.94 12.69
Nett VAT
Digital Multimeter..............00..-000c000 000 2700 216 2916 6820 PIO... i... ye a
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Q.E.D. MAINS INTERFERENCE SUPPRESSOR TIL 311 dot format hexadecimal display, fits 14 pin
DIL socket, incorporates TTL compatible four bit
Computers are especially prone to interference from spurious signals in the main latch, decoder and display driver
supply. This ‘unit cures most forms of this interference. Maximum current 3 Amps. 6.25 0.506.75
Nett VAT Total PROGRAM NAME
SUPP OSSON: 255g .5.1a:s% 0, ore: sey a share oven horse euvnonore Mehonenaly 10.83 1.35 12.18 1 Fo a (2
MACHINE
S & R BREWSTER SOLDERING EQUIPMENT i Nin
We stock and recommend the SRB Type 1 miniature soldering iron which is ideally QUALITY
suited in size and power to printed circuit work. The negligible current leakage is DATA
especially useful when dealing with CMOS devices and interchangeable bits provide MICRODIGITAL LID «assert
sufficient versatility.
LOOK FOR THE LABEL!
Nett VAT Total
Type 1 Soldering Iron 16-18 watts with 3mm bit 3.50 0.28 3.78
a 3 : The Micro-Digital ‘own-brand’ C15 Cassette means high
Stands aearated Crreul desotdening TT Soa 02a 3.28. | sual specially madefor your micro-computer
Spare) bit Wavertree oes Ps ee oe ware ae 0.41 0.03 0.44 %* Tape made against DIN reference tape 45513/ 16
Long Life bit peavatsdavenstersl-veetetiets tale, s) MOAN 10. gttielie; eiipiis oe 0.88 0.07 0.95 C528V with anti-static carbon additive.
n Z " % Five screw case fixing and transport mechanism using
; precision stainless steel roller axles.
TEXAS INSTRUMENTS TI PROGRAMER CALCULATOR % Two special graphite impregnated slip shields guide
; : tape edges to prevent pack scramble and dispel
Designed for the computer user this calculator has the following features: residual static
1. Quick accurate conversion between numbers base 8, 10 or 16. ; Nett VAT
2. Calculations in all three number bases. 10 quality C15 cassettes
3. Logical functions: AND, OR, EXCLUSIVE OR, SHIFT. with library cases &
Operating bit by bit on numbers in HEX and OCT. special labels
4. Handles mixed number bases and combined logical and arithmetic operations,
taking place automatically in user specified order. Total £4.75 (inc. P & P)
5. Constant with all arithmetic and logical operations.
Nett VAT Total
TI Programmer, ...2......005ce cence enc eee cee 46.25 3.70 49.95
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