The 200 mph micro
Imagine installing a microprocessor on a Formula 1
racing car. This was just one ofthe varied tasks given to
Scicon’s Micro Systems team. Speed, suspension
movement, g-forces and chassis roll were the parameters
that had to be measured. Vibration, interference, weight
and temperature were just some of the problems to
contend with.
Our Micro Systems team took it in their stride and
came up with an innovative solution. They are also at home
with commercial, industrial, scientific and military
applications.
For further information about Scicon’s capability in
micros circle No. 101 on the free reader enquiry service. We
can’t offer you a drive around Brands Hatch but we can offer
you fast, effective solutions to your special microcomputer
requirements. Or if you like the sound of working for a team
involved with advanced technology telephone or write to-
John Howes, 01-580 5599. Scicon Micro Systems,
Scientific Control Systems Limited, Sanderson House,
49-57 Berners Street, London W1P 4AQ.
Scicon
MICRO
SYSTEMS
Contents
PET REVIEW
We review the Commodore Pet, a £700 com-
puter system which is being used by hobbyists
and businessmen.
Page: 21
BUDGET TERMINALS
We look at two visual display terminals for
less than £400 from Strumech Engineering and
Computer Workshop.
Page: 38
PROGRAMMING FOR VAT
The first of two articles containing a complete
suite of programs written to handle VAT
accounting.
Page: 59
ILLUSTRATING BASIC
We begin a teach-yourself-Basic series, based
on Donald Alcock’s famous Illustrating Basic
book.
Page: 45
COMPUTING IN SCHOOLS
A behind-the-scenes look at how Cornwall
Technical College is building and using micro
systems.
Page: 32
COMPUTABITS
In addition to the VAT programs, our Computa-
bits columns look at the CP/M operating
system and a user library for CP/M; how to
wire KIM as an electronic organ; and what the
new programming language Pilot will mean to
micro users.
Page: 59
WIN A COMPUTER
Your chance to win your own computer. Details
and entry form.
Page: 27
AND MUCH MORE
Letters, page 9; Printout, page 13; Micros or
calculators? page 17; A look at Computer
Workshop, page 28; Off-beat computing in
Surbiton, page 42; Book reviews, page 55;
Glossary of computer terms, page 70.
PRACTICAL COMPUTING October 1978
¢-@ Circle No. I0!
MK14-the only low-cost keyboard
-addressable microcomputer!
The new Science of Cambridge MK14
Microcomputer kit
The MK14 National Semiconductor
Scamp based Microcomputer Kit gives
you the power and performance of a
professional keyboard-addressable unit
- forless than half the normal price.
It has a specification that makes it
perfect for the engineer who needs to
keep up to date with digital systems, or
for use in school science departments.
It’s ideal for hobbyists and amateur
electronics enthusiasts, too.
But the MK14 isn’t just a training aid.
It's beendesigned for practical performance,
so you canuse it as a working component
of, even the heart of, larger electronic
systems and equipment.
MK14 Specification
Hexadecimal keyboard
8-digit, 7-segment LED display
512 x 8Prom, containing monitor
program and interface instructions
256 bytes of RAM
4MHz crystal
5V stabiliser
Single 6V power supply
Space available for extra 256 byte
RAM and 16 port 1/0
Edge connector access to all data
lines and 1/0 ports
i
+
Free Manual
Every MK14 Microcomputer kit includes a
free Training Manual. It contains
To: Science of Cambridge Ltd,
6 Kings Parade, Cambridge,
Cambs., CB21SN.
Please send me an MK14 Standard
Microcomputer Kit. | enclose cheque/
Money order/PO for £43.55 (£39.95
ide 8% VAT and 40p p&p).
=e
operational instructions
and examples for training applications, and
numerous programsincluding mathroutines
(square root, etc) digital alarm clock,
sIngle-step, music box, mastermind and
moon landing games, self-replication,
general purpose sequencing, etc.
Designed for fast, easy assembly
Each 31-piece kit includes everything you
need to make a full-scale working
microprocessor, from 14 chips, a 4-part
keyboard, display interface components,
to PCB, switch and fixings. Further software
packages, including serial interface to TTY
and cassette, are available, and are
regularly supplemented.
The MK14 can be assembled by anyone
with a fine-tip soldering iron anda few
hours’ spare time, using the illustrated
step-by-step instructions provided.
Tomorrow’s technology - today!
“Itisnot unreasonable to assume that
within the next five years... there willbe
hardly any companies engaged in
electronics that are not using micro-
processors in one area or another.”
Phil Pittman, Wireless World, Nov. 1977.
Name
The low-cost computing power of the
microprocessoris already being used to
replace other forms of digital, analogue,
electro-mechanical, even purely
mechanical forms of control systems.
The Science of Cambridge MK14 Standard
MicrocomputerKit allows youtolearnmore
about this exciting and rapidly advancing
area of technology. It allows you to use
your own microcomputer in practical
applications of your own design. And it
allows you to do it at a fraction of the
price you'd have to pay elsewhere.
Getting your MK14 Kit is easy. Just fill in
the coupon below, and post it to us today,
with a cheque or PO made payable to
Science of Cambridge. And, of course, it
comes to you with a comprehensive
guarantee. If for any reason, you’re not
completely satisfied with your MK14,
return it to us within 14 days for a full
cash refund.
Science of Cambridge Ltd,
6 Kings Parade,
Cambridge,
Cambs., CB21SN.
Telephone: Cambridge (0223) 311488
—————-------------------—--- 5
‘staeamm ——— SINCE OF |
—____— Cambridge!
Allow 21 days for delivery.
PC/9
@ Circle No. 102
PRACTICAL COMPUTING October 1978
Practical
Computing
Managing Editor
Dennis Jarrett
- Computabits Editor
Nick Hampshire
Production Editor
Harold Mayes
Advertisement Manager
Erica Gibson
Subscription Manager
Annabel Hunt
Publisher
Wim Hoeksma
Publishing Assistant
Carole Fancourt
Managing Director
Richard Hease
Editorial, Advertising and
| subscriptions: 01-278 9517.
Practical Computing is published
by EEC as a subsidiary of
WHICH COMPUTER? Ltd at its
registered office, 2 Duncan
Terrace, London, NI, and printed
by Bournehall Press Ltd,
Welwyn Garden City. Distributed
by Moore Harness Ltd, 31 Corsica
Street, London, N5.
© Practical Computing 1978
ISSN 0141-5433.
| Subscription rates: Single
copy: 50p. Subscriptions: U.K., £6
per annum (including postage);
overseas, £12 (including airmail
postage).
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 October 1978
(5
We will pay £5 for the best letter published each month. Here is this month’s
winning letter:
Home-brew club for London
ON WEDNESDAY, October 5 at 6.30 pm, we
are holding the inaugural meeting of the
North London Hobby Computer Club in
Room 47 in the Olid Polytechnic Building
at Holloway Road, just opposite Hollo-
way Road underground station on the
Piccadilly Line.
The Department of Electronic and
Communications Engineering and the
Polytechnic of North London have made
available many resources for this venture.
Within the department there are two
Pets, with a third coming, four SWIP
6800 computer systems, with floppy discs,
printers and VDUs and some Kim and
Motorola microcomputer systems. Most
will be available for use, as will some
Pets and SWTP systems in other depart-
ments.
As we.envisage the club at the moment
little ‘““home-brew”’ activities are anticipat-
ed before Christmas, with any meetings
centring on talks by manufacturers and
discussions on programming.
From the New Year, however, we anti-
cipate three sets of activities running con-
currently, or sequentially—it all depends
on how many people turn up. They are
short courses on programming, Basic and
machine level; a home-brew section using
the facilities of the department—up to 35
people can solder and test at the same
time—and introductory talks and dis-
cussions for those anticipating their own
systems.
AS you can see, we are preparing a
varied programme which should be of
interest to a wide variety of people.
Obviously, students from the Poly will be '
coming, but we want to emphasise that
this is a club open to all interested. The |
Poly will be providing some back-up,
especially with expert staff and other
facilities. This is all part of the Com--
munity Development Programme institut- '
ed recently.
I hope Practical Computing will be able
to help us get this off the ground. Those
organising it are members of the Amateur
Computer Club, as well as lecturers in |
digital electronics.
Robin Bradbeer,
Senior Lecturer,
Acting Club Secretary
MPU system prices
THERE has been some controversy re-
cently concerning the price of American
MPU systems in the U.K. There are com-
panies who simply change the $ sign for a
£ sign and call that the U.K. price; most
are more reasonable. My own company
does not, as yet, sell any American sys-
tems—we build our own—but recently I
have been working out some figures.
Let us take as an example a reasonably-
sized American microcomputer system
which sells for a basic $2,000. A U.K.
agent receives 25 percent discount but will
usually have to order 10 units at a time; he
therefore puts up $15,000. This is prob-
ably done by letter of credit; it could be
three months before he gets delivery.
Adding interest charges at 10 percent
on $15,000 for three months produces a
total outlay of $15,500. Add freight and
duty to the imported product and you
finish with a total outlay of $18,000 for
10 units. A quick conversion reveals this
to be about £1,000 per unit. You can
count in another 15 percent for technical
back-up and physical stocks; then there
will be a 50 percent mark-up. You end up
at about £1 ,600-£1,700.
Why should the U.K. dealer receive the
equivalent of 30-40 percent discount when
his American cousin gets only 25 percent?
There are several possible reasons:
Low-volume sales compared to the U.S.
market which is 12-18 months ahead of
ours;
Need for more technical back-up due to !
the low level of customer education in
U.K.
Part of the profits may be disappearing to
a central European distribution office in
France, Germany or Switzerland—this
may also include currency conversions
which work to the benefit of the Euro-
peans, so the U.K. dealer may be getting
only about 25 percent discount.
Because of hobby magazines, local com-
puter stores and the next-door neighbours,
the average American buyer has a good
idea of the product and price before he
shops. His U.K. counterpart will want
several demonstrations and a long talk |
with an expert before he even considers
taking away a data sheet to study. So the
actual cost of each sale is higher in the
U.K. than in the U.S.
Sales volumes are low because of the
relatively high prices of the equipment in
the U.K. Even if the U.K. dealer made no |
profit and sold the example system for
£1,000, this probably represents a quarter {
of the average annual salary for a pro-
grammer or engineer, the most likely
first customers.
In the U.S. the typical engineer or pro-
grammer can expect to get about $20,000
pa; our $2,000 example is equivalent to
only one-tenth of his salary.
This difference is magnified by the
higher salary rate paid to foreign engin-
eers and the costs of importing, including
(continued on page 11)
LET YOUR SYSTEMS GROW WITH S.E.E.D.
Please send S.A.E. for details to:-
STRUMECH ENG. ELECTRONICS DIV.
PORTLAND HOUSE, COPPICE SIDE, BROWNHILLS, WALSALL
“Sole U.K. Distributors’’
| \_ THE NEWBEAR COMPUTING STORE
The Bear announces its new store at:—
2 Gatley Road,
Cheadle,
Cheshire
Tel: 061-491 0134
callers welcome, mail order to Newbury.
PETITEVID VDU KIT ¢85
(10 to 1,200 baud V24, 64 ch x [6 line scrolling, all on
8in. x 4in. PCB. Needs TV set, UHF Modulator and
ASCII keyboard.
BOOKS
Computer designs. 77 68 2 6800 arcreco meer: dee
Spare diagram set for 77-68 =.
WB-1 a TTL Microcomputer
Spare diagram set for WB-#
Zilog Z-80 Technical Manual
Z-80 PIO Manual
Z-80 Programming Manual ‘
Motorola. Understanding Microprocessors
M8800 Microprocessor Ecoaremming’? GLUE:
M6800 Applications Manual ..
4.0.58. Technology KIM | Us
6500 Programming Manual
6500 Hardware Manual
Adam Osbourne Introd:
Vol. 0 Beginners Book .
Vol. | Basic Concepts
Vol, 2 Some Real Products
8080 Programming for Logic Design
6800 Programming for Logic Design
Some Cammon Basic Programs x
Payroll with Cost Accounting In Basic .
Sybex Microprocessors
Microprocessor interfacing Techniques C20 .....
Scelbi 8080 Software Gourmet Guide Cookbook
6800 Software Gourmet Guide Cookbook. .
The Scelbi Byte Primer
What to Do After you Hit Return ‘ _
PCC Reference Book on Home Compucers:
Instant Basic
My Computer Likes Me a
Games with a Pocket Calculator ....
Games Tricks & Puzzles for a Hand Calculator .
Best of Creative Computing Vol. |
Best of Creative Computing Vol. 2
Hobby Computers are here...
Best of Byte .....
101 Basic Computer G:
The Home Computer Revolutios
Computer Lib
Firse Book of Kim ....
BG=GR GRESTHSBSoSsg
RASRR 8B
REDDOGROBS SERS
sSaseseaeses
pensese
aaa
agonee
S26S23
SC/MP Mk IL
SFF96364
MC1488P .
MCI489P .
7SISOP ...
75150N ......
75154 ....
4N33 ..
Hardware Components Section
MEMORIES
€-25
£035
3-04
-£850
4027 :1250ns ..
2144 (450ns) .
4116 (250ns) to
2708 (450ns) ...
2716 (41)
SPECIAL MOTOROLA
MICROCOMPUTING ICs
S ois aiabelaceeeletaie £9-26
- £463
B00
él
- £1550
-£10 00
.£10 00
SWATBUG _-
MC6830L7 ...
MCs602P_.....
MCI4S38P
MC3459
Z-B0A CPU .....
Z-B0A P10 .
Z-B0OA CTC .
MICROPROCESSORS
£10-30
6502 £14.93
8080 £600
INTERFACING ICs
vbDU
- -£1-30 For ¥24
« €1-20 RS232C
. 2:50
- 19S
AY-S-1013 _
8402,
TALSOO . .
TALSOL .
TALSO2 .
74LS03 .
TALSO4 .
TA4LSO5
74.508 .
TALSOP .
TALSIO.
TALSIE...
74LSI2 .
TALSI3
TALSI4 ..
TALSIS .
TALS20 .
TALS21 .
74LS22 |
TAUSIG cs scam
TALSZ7 .
74LS28
BUFFERS
74LS 109
74LS112
TALSI13
74LS114
7418125
745126
74L$132
7418136
- £450
-£10 00
-£19-00
. £1050
745138 |...
TALSI39 .
TALSIS1
TALSIS3
TALSIS4 ..L€t
TALSI5S
TALSIS6 ...
74LS157
74LSISB -
TALSI60 ...
ecc—
NEW RANGE OF LOW COST S/00 8K RAM
BOARDS, PCBs, ETC... PLEASE SEND FOR
LATEST LIST.
BEAR BAGS (Kits)
77-68 components and edge connectors
68 Led's and switches
Power Supply
9” Sa Rack and Backplate .. es
4K Ram PCB and components .....
Mon ( PCB and components
Ram Exorciser PC8 and components
B8K Ram Exorciser PCB and components
9 Petitevid VDU Kic sree
10 Kansas Cicy Cassette interface.
11 UHF modulacor .
4277 68 VDU e
Available direct from us or from your “focal “Bear Bag Stockist
(dealer enquiries welcome).
VIM I
The new 6502 based micro from Synertak. Fully assem-
bled and tested £199.00 plus 8% VAT. Send for data
Sheet. Carriage £1.00.
PCB and‘ COMPONENTS
77-66 PRINTED Sey BOARDS
Soft Monitor ....
VOU Keyboard Interlace
ROM Monitor .
Veroboard 8 x B .
Veroboard backplate 8 x iv
Hexadecimal Keyboards .
FND 500 7 Segmenc disp!
Decoder chip
ASCII Keyboard (unencoded) .
Keyboard assembled and tested.
Keyboard case
Goods are normally shipped within 24 hours, subject to availabil-
ley. Barclaycard & Access. VAT at 8% for Hardware Components.
30p postage and packing unless otherwise stated. Cheques to be
made out to The Newbear Computing Store. Send for an up-to-date
catalogue to The Newbear Computing Store, 7 Bone Lane, Newbury
0635-49223. Callers are welcome Monday to Saturday 9.00a.m.-
§5.30p.m., bue please ring to let us know when you are calling.
@ Circle No. 108
PRACTICAL COMPUTING October 1978
(continued from page 9)
the profits made by the foreign designers
and manufacturers.
At present, the U.K. boasts something
like six companies making home and
small business computers based on micro-
processors, my own company being one of
them. Recently we had 95 percent of our
kits waiting on the shelves for three
months, due to the ‘memory famine’.
| During that time we have had to watch the
customers dwindle and the bank overdraft
| charges rise. We hope soon to be able to
deliver from stock, but the majority of the
advertising and selling done three and
‘| four months ago has been wasted. Other
U.K. companies are in similar situations
for various reasons.
The Government is considering invest-
ing £50 million in a product which has not
yet been designed (the 64K RAM) to be
made in a factory which has not yet been
built. Foreign manufacturers are already
beginning to produce prototypes to be
made by experienced personnel in existing
factories.
Why not invest some of that £50 million
in an attempt to stimulate a home market
by reducing the prices of the end products?
There are several U.K. companies capable
of designing better microcomputers than
the Americans and with the world-famous
U.K. software in them.
As an example, we considered buying
an American microprocessor develop-
‘ment system for £365; in fact, we designed
our own with improved hardware, better
interface facilities, and much-improved
software. It sells for £155, less than half
of the American equivalent. A fall in
component prices of about 25 percent
helped but, even so, we could have done
it for about half the cost of any equivalent
American design.
Apply this philosophy to our $2,000
product and it would end up at about
£700; and a simple home computer, such
as those currently selling at £500-£700,
could be built for £350-£400.
Let others cut their own throats in the
component business but let us take ad-
vantage of the low costs which result,
capitalising our own hardware and soft-
ware design capabilities to make systems.
We have managed to sell the idea of
Teletext and Viewdata to most of Europe;
we should now follow with compatible
low-cost microcomputer systems. When
we have a large home market and a good
share of the world market for micro
systems, it may then be time to look at the
idea of IC manufacturing in the U.K.
In the meantime, spare another thought
for the ‘ridiculous’ profits made by im-
porters of American systems. Some of
them are genuinely interested in making
a market for home computers in the U.K.
If the Government is not going to help,
the money has to be raised somewhere.
John H. Miller-Kirkpatrick,
Technical Director,
Bywood Electronics.
Question of
logistics
I READ with great interest the article which
appeared in the July/August issue of
Practical Computing.
Concerning the brief history of the
personal computing industry, I must say
that I think the NASCOM 1 success story
tends to conflict with the conclusions you
have drawn in your article and I would
welcome the opportunity to expound this
company’s philosophy as far as the ama-
teur market is concerned.
I am sure you are familiar with NAS-
COM | and I am also of the opinion that
you will understand the original philo-
sophy behind its design to some degree
discounted and offset the factors you out-
SE Ae EP
lined in the early part of your article
concerning relatively high prices on a
cash-in-advance basis for something which
proves to be of dubious engineering stan-
dards.
While I would be the first to concede
that we have not been able to attain the
delivery schedules we had anticipated, this
was not for the reasons you have outlined
but for the logistics of dealing with an
indigenous manufacturer in the U.K.
I am pleased to say that our company
enjoyed a great deal of interest at the
Do-it-Yourself computer show and this-
has been followed by a reasonable number
of confirmed orders. It is our intention to
stay in the forefront of microcomputer
design and development and we will
always aim a portion of our marketing
effort and expertise towards the bottom
end of the market you say is developing,
namely the amateur enthusiast.
I would like to wish your magazine
every success in the future as I feel that
dedicated publications to this new indus-
try are of benefit to manufacturers and
customers alike.
J. A. Marshall,
Managing Director,
Nasco Sales Ltd,
Chesham, Bucks.
For the record
MY COLLEAGUES and I would like to point
out some errors in biographical details at
the end of your reprint of our On-line
paper, Microcomputers in the Construc-
tion Industry.
John Paterson is a lecturer at Reading
University. Ted Cogswell is a lecturer at
Southampton College of Technology. My
surname is Frith, not Firth.
J. Frith
University of Reading.
Feedback for you
WHETHER you are using or contem-
plating the use of computers in the
home, in business or in education, the
we receive.
Practical Computing Feedback columns
may be of help to you.
Starting next month, Feedback will deal
with your problems. If you want to know
If we cannot answer your query, we will pub-
lish your request and pass on the replies
Feedback will also be a forum for any inter-
esting developments you may have made.
how to put a system together, or to find
out what is available from where and at
what price, tell us about it and we will do
what we can to assist.
; es
PRACTICAL COMPUTING October 1978
Please let us know about them, so that we
can tell others.
Write to Feedback, Practical Computing,
2 Duncan Terrace, London, N1 8BJ.
We look forward to hearing from you.
Pets in the
kitchen
EAST meets West at the Orient
Restaurant off Tottenham
Court Road in London. East,
represented by Chandru Idnani,
who owns the restaurant, is
supplying initiative and exper-
tise, while West—or to be more
accurate South-West Techno-
logy—adds hardware, the re-
sult being a computerised res-
taurant.
Chandru claims that when
his system becomes fully opera-
tional it will be the first of its
kind, helping waiters and kit-
chen staff to keep track of
orders, preparing bills, con-
trolling stock levels and per-
haps eventually moving into
the more mundane area of
payroll.
Nor does he intend to keep
it to himself. ‘““We’ve tried to
make it as universal as possible,
so that it can be used in other
types of restaurant,” he says.
To this end he is preparing to
open a computer store on the
floor above his restaurant,
there to sell packages not only
to caterers but also to other
businesses whose functions he
thinks can be computerised in
a similar way.
Baking hot
As you may imagine, he is a
man of considerable energy
and expertise. He also has a
background in mathematics
and a degree in physics at
University College, London,
where work with a research
group introduced him to com-
puter hardware. That was in
the late 1960s but it was not
until the end of last year that
he decided that micros could
benefit his business.
He left the academic life for
catering in 1969 and has looked
at various ways of mechanising
the business since then. A
scheme to automate the pre-
paration of some dishes—to
enable him to maintain the
standard of food when the chef
was ill or on holiday—proved
impossible to put into practice
but he succeeded in simplifying
the baking of bread, a task
which had formerly required a
man with an asbestos forearm.
Chandru has been working
now on the computer system
for about five months and
expects to have it running in
another month. It uses an
SWTP 6800 with 40K bytes
of RAM, a cassette interface,
keyboard and printers.
He has added “bits and
Pieces to the micro” but it is
the software which has delayed
him. “I thought it would be
very easy but in the end I had
to get experienced help.” The
experienced help came from
friends but even so he has
written much of it himself,
having learned Basic from
scratch. when it’s finished the
program should run in about
16K.
Coded orders
The program has two major
loops—one for overall control,
the other for the processing of
customers’ orders. When the
restaurant opens in the morn-
ing there are the usual initiali-
sation procedures—entering
the date, marking any items
from the 180 on the menu
which are not available, and
setting totals to zero if required
So business begins. A waiter
—identified by a code—takes
orders—broken into coded
items from a table, which is
again given a number. There is
nothing unusual so far but the
waiter then takes his notebook
to the bar and details of the
order are typed into the sys-
tem from a numeric keypad.
The ‘order loop’ has three
options; to initiate an order, to
add to it, or to produce a bill.
In the first and second cases
the order will be transmitted to
a PR40 printer in the kitchen;
a second printer will be kept
behind the bar to print bills.
Chandru is using rolls of paper
4} in. wide for this purpose.
When the customer pays, the
system records the method and
size of payment, handling
credit cards, luncheon vou-
chers and complimentary
meals as well as cash. At the
end of a day’s trading a re-
conciliation can be produced
and a list showing the totals of
each item ordered during the
day. By comparing this list to
stock input, Chandru has an
immediate balance of stock
and a guide to future buying.
There are other incidental
benefits—menus printed daily,
infallibly accurate and legible
bills, and possibly improved
service. The cost has hardly
been prohibitive; Chandru es-
timates £2,000 for the hard-
ware and plenty of goodwill
for the software.
The customer will probably
notice very little difference—
the only immediate sign will be
a line reading Bill Produced By
Computer at the foot. Grafton
Way’s only oriental dancers
may well cause them to over-
look even that.
Chandru also has a Com-
modore Pet which he hopes to
use in the restaurant when he
can attach a printer to it. His
ideas on the future develop-
ment of the system include
both machines. He thinks it
could be particularly useful to
English restaurants which, un-
like his own, tend to change
their menus from day to day.
He also sees a market for a
grocery package, with the em-
phasis on stock control with,
say, 500 items. Putting his
money where his mouth is,
his computer store will be open
in four to six weeks.
When Chandru spoke to
Practical Computing he was
joined by the district’s former
health inspector, who had only
praise for the restaurant and
showed no sign of alarm at the
thought of Pets and suchlike
in the kitchen. That is progress
indeed. i.
Checkmate for Ian
IF you are used to cramming
your programs into systems
with only 2K of memory, you
will have little sympathy with
Ian Toyn, a 16-year old school-
boy from Lincoln. He has just
written a chess-playing pro-
gram but cannot test it as it is
too big even for the mainframe
at the local College of Tech-
nology to handle.
Ian is at Yarborough High
School, Lincoln, where the
maths department has been
running courses since 1976.
A Teletype terminal at the
school sends programs and
data to the College of Techno-
logy for processing. Ian’s pro-
gram, however, is so big that
until the college expands its
system, he will not be able to
run and debug it, so it looks
like checkmate. wl
PRACTICAL COMPUTING October 1978
TALKING TO
YOUR APPLE
“I TALK to the trees’, ran the
song. A silly thing to do,
perhaps, but there is an inani-
mate object to which you can
talk which will understand you,
the Apple II micro system.
Keen Computers of
Nottingham, which markets
Apple products, is selling a
voice input system which
allows you to give spoken
commands to your machine.
The system is called the
Speech Lab Model 20A and
costs £165. It comprises a
microphone, the voice recogni-
tion board, manual, and six
demonstration programs.
The programs are either tape
or listings and allow the begin-
ner to do voice prints on the
screen; play Mastermind and
Blackjack; teach the cursor to
go up and down, left and right;
recognise people by their
voices; and play Shooting
Stars.
As Keen says, the advan-
tages of using voice input are
enormous, as ‘“‘speech is a
human’s highest capacity
Output channel”’.
Two models
Speech Lab is in two models.
Model! 20 has a vocabulary of
32 words. It is available as the
20S for S-100 computers and
the 20A for the Apple II unit.
Features include:
ROM.-based software with a
re-locatable program so that
you can load it anywhere you
have memory; after loading,
the 2K ROM can be disabled
under computer control.
The speech recognition pro-
gram, callable from any Basic,
requires 4K bytes of RAM
supplied by the user, which can
be located anywhere in the
address space.
Hardware includes two
band-pass filters with two bits
of amplitude, two zero crossing
detectors and a linear amplifier.
A combined _hardware/
software manual includes 10
experiments.
Model 50 is an S-100 bus
compatible system (8080 or
Z-80) capable of handling a
64-word vocabulary, using 64
bytes of storage per spoken
word. Features of Model 50
include CMOS design for
reliability and low power con-
sumption. Response is real-
time.
Software for Speech Lab
includes seven complete pro-
grams, three of which are
offered in source and on paper
tape and four in source alone.
The three paper tape and
source are: speech basic pro-
gramming language; assembly
language recognition program;
and hardware self-test pro-
gram.
The source programs are
provided in Speech Basic to
plot and correlate speech data.
Two recognition programs
offered will clarify speech con-
cepts.
The assembly language pro-
gram uses less than 4K_ bytes
for a 32-word vocabulary and
it loads at 100H. A high-core
version is available. [yj
Home keyboard
SIRTON PRODUCTSs has produced
a very cheap ASCII keyboard
for use with any home micro
system. It costs £88.50 and is
complete with case, power
supply and UHF modulator, so
that it can be plugged straight
into a domestic TV set.
Sirton also offers a_ self-
contained VDU system which
gives a display of 16 lines of 64
characters. In addition to
normal cursor controls, it can
present reverse video—black
on white—and the facility to
make the whole screen or
selected characters flash to
A voice response unit working on the Apple II.
PRACTICAL COMPUTING October 1978
attract the attention of the
operator.
Further details: Sirton
Products, 13 Warwick Road,
Coulsdon, Surrey CR3 2EF.
Telephone: 01-660 5617. J
Addition to
family
CHIP manufacturer Zilog has
expanded its MCZ-1 family of
microcomputer systems with
the introduction of a new
business system, the MCZ-
1/60. Like other systems in the
range, it is based onthe Z80
| microprocessor.
It is equipped with a display
and keyboard and two floppy
disc drives. To make it accep-
table in the business environ-
ment, it can be programmed in
standard Cobol, as well as
PLZ and two versions of Basic.
The minimum configuration
costs £5,300, and has 32K
bytes of main memory, ex-
pandable to 64K.
The MCZ-1 range starts at
around £3,500 for the model
01 and is marketed in the
U.K. by Memec Systems, of
Thame, Oxfordshire. |
Design
courses
A SERIES Of three-day courses on
the design of micro processor-
based systems has been set up.
Day | of the course is en-
titled Microcomputer Sys-
tems-Fundamental concepts,
day 2, Microcomputer Inter-
facing and Programmable
Devices; and day 3, Micro-
computer Software and Pro-
gram Design.
Details from Prodex'(Semi-
nars) Ltd., 79 High : Street,
Tunbridge Wells, Kent TNI
1XZ; telephone 0892 39664.
Catalogue |
update
PETSOFT, the microsoftware
house specialising in programs
for the Commodore Pet is now
updating its catalogue of
more than 60 titles monthly.
New programs include
stock control, sales analysis,
reformat, Life, and a back-
gammon program which dis-
plays the board, ‘shakes’ the
dice, and plays either the Pet
user or itself.
Petsoft says the introduction
of business and application
software has generated sales to
universities, banks and large
corporations, including ICI,
-Rank and the Post Office.
Special high-energy, low-
noise cassettes chosen for their
low drop-off characteristics, in
the short C-12 length, cost
£4-75 for 10 plus 5Op postage,
or £45 for 100, carriage paid in
the U.K.
Catalogues can be obtained,
from Petsoft, PO Box 9,
Newbury, Berkshire, RGI3
iPB. Telephone 01-353 1100,
and 0635-201131. im
———— a
Single Disk 143K £453
Dual Disk 630K £1159
Include PSU, S100 controller,
Basic/MDOS.
Add-on 143K £399
Add-on
630K £859
Office Hours:
Monday - Saturday
Access/Barclaycard
Prices exclude VAT/CARR
Bet with
“ECsTASY’” may not be the first
thing to register when calcula-
tors are mentioned and it does
not occur often in the presence
of bookmakers, either—unless
you win, of course.
Efficient Computing Systems
of Douglas, Isle of Man, how-
ever, has put together a system
based on a Texas Instruments
T1-58 programmable calcu-
lator, called it Ecstasy, and
made it essential equipment for
many local bookmakers.
The key to the betting shop
application of the TI-58 is a
device known as the Custom
Host $100 computer with 32K and
1/0 card
From £1200
Ecstasy
CROM—which | stands for
Constant Read-Only Memory.
It is a small module which con-
tains special programs develop-
ed by Dr Les Waller, a con-
sultant to ECS.
The programs, which Dr
Waller designed to be econom-
ical in terms of memory usage
and number of steps, can calcu-
late complex bets from double
to Yankee in one operation.
Further information: John
Gibbons, Texas Instruments.
Telephone: Bedford 67466; or
Dr Les Waller, Middles-
borough 85399. fal
Mersey
beat
micros
LIVERPOOL has acquired a
micro shop, Micro Digital,
spawned by Datapool Services,
a computerised book-keeping
bureau based in the city.
Bruce Everiss, the managing
director, is casting the net very
wide and the bureau parentage
means a strong bias towards
the small business market. The
shop caters for customers
wanting dedicated micro-packs
and general-purpose micro
systems and kits.
Initially, it is acting as a
showroom for Apple, Nascom,
Casu and Cambridge Mark 14.
Micro Digital is geared to-
wards the hobbyist and the small
business. Everiss reckons to be
able to supply tailored sys-
tems to most requirements and
with that in mind is developing
a system around the Z80 and a
British-made S100 bus.
Micro Digital is at 25
Brunswick Street, Liverpool 3;
you can cal! on 051 — 708 8624.
Open from 9 am to 5.30 pm. fj
SINTROM
——, «aaah means
business
From an established base in scientific, educational and personal computers using SWTPC 6800
and S100 8080 equipment, Sintrom announces a range of small systems for the business user.
Easy availability of Micropolis-compatible applications software plus CP/M, COBOL, APL,
FORTRAN and BASIC allows a speedy implementation of the total system.
@Ledger @Payroll@inventory @Word Processing@High Resolution Graphics@ Industrial Control
ADM 3A VDU
£620
Centronics pPrinter £350-£400
Centronics 701
Plus integral dual Disk
From £2200
Write for
free catalogue
a
[° SJ
SINTROM GROUP
£1400
Sintrom Microshoo
Arkwright Road,
Reading, Berks. RG2 OLS.
Tel: Reading (0734) 84322
@ Circle No. 109
PRACTICAL COMPUTING October 1978
PAST Tse |
Expertise
the key
PETS and Apples are now being
sold in Tottenham Court Road,
London, W1 by Euro Calc.
The shop, which has been
specialising in calculators, has
now added these computers to
its range of equipment.
Tony Manton, who runs the
shop, explains that Euro Calc
is concerned mainly with sell-
ing ready-built systems, for
which it will supply software
development effort and ex-
pertise rather than kits.
The shop opens from 9,30
am to 6pm (7pm on Thurs-
days) at 244 Tottenham Court
Road, London, WI. Tel:
01-636 8161.
Close to Euro Calc is
Heathkit,
visit.
which is worth a
Calculator
packages
TEXAS INSTRUMENTS has set up a
library of cheap software pack-
ages for use on its program-
mable calculators. The library
is called the Professional Pro-
gram Exchange and includes
hundreds of ready-written pro-
grams which users of TI-58/59
calculators can buy for $3 each
—that’s about £1.60.
It costs $15 (£8) to join the
exchange and membership
includes a catalogue listing
all the programs available.
Twenty separate categories are
covered, including games, en-
gineering and finance.
As well as buying packages,
uSers are being encouraged to
contribute their own programs
to the library. Prizes are offered
to those whose software is
approved and added. al
PRACTICAL COMPUTING
Back-up storage
for Zilog Z80
ANYONE with a microprocessor
system based on the Intel 8080
or Zilog Z80 and in need of
more back-up storage should
be interested in a new product
being marketed at the Sintrom
Microshop.
The Micropolis Meta Floppy
1054 it is a four-drive mini-
diskette unit. It takes four
Shin. high capacity floppy discs
and provides 1:26 million
bytes of on-line storage.
That exceeds the capacity of
many larger floppy disc drives
and Sintrom claims the 1054
has a number of exceptional
technical features which make
it possible. Not only is capa-
city high but performance is
very respectable, too. Track-
to-track access time is 30
milliseconds and data transfer
can be as high as 250,000 bytes
per second.
One other handy feature is a
disc insertion interlock which
prevents accidental damage to
the disc by ensuring that the
user cannot close the drive
door until the disc is positioned
properly. An illuminated dis-
play always shows the logical
Tune in to
Crystal
TORQUAY now has a micro
shop, Crystal Electronics, run
by Trevor Brownen and his
wife. They have the agency for
Apple, Nascom and Newbear
—whose Bearbags must be one
of the neatest pieces of mar-
keting in the field.
As well as supplying kit—
and Crystal is the only agency
south of Bristol, Brownen
believes—there is an in-built
consultancy service, since he
likes to spend time discussing
customers’ requirements and
advising them on their sys-
tems.
Brownen’s background is in
electronics and computers and
the consultancy is free. The
shop is at 40, Magdalene Road,
and is open from 9am to 5pm.
Although you might have to
wait a week or so for some
items, Brownen is confident he
will be able to satisfy most re-
quirements on a_cash-and-
carry basis shortly. Call Cry-
stal on 0803 — 22699.
October 1978
address of each drive to pre-
vent operating errors.
The 1054 is complete with
controller, power supply, chas-
.sis, enclosure, cabling and a
new Basic software package.
The Micropolis Disc Exten-
ded Basic includes a new
chain command which allows
the user to split large programs
into segment. Each segment
resides on disc and is called
into main memory when re-
quired—the technique referred
to as virtual storage in ‘the
world of mainframe compu-
ters. The 1054 costs £1,999.
Further details from Sintrom
Electronics Ltd, Arkwright
Road, Reading, Berkshire.
Telephone, Reading (0734)
85464.
THE COMMODORE Kim 1 micro
has been extended by GR
Electronics of Newport with
the addition of a video board,
additional memory, a pocket
terminal and a range of soft-
ware products.
With the video board a tele-
vision becomes a VDU with
16 lines of 64 characters. At
£150 this item costs £1 more
than the Kim 1 itself. The
Memory Plus board contains
8K bytes of random access
memory and provides for up to
8K. bytes erasable programm-
able read-only memory. It
costs £199.
The GR Electronics pocket
terminal, costing £240, allows
input of the full ASCII charac-
ter set. iz
Home computer coupling
in which to program it
ae /
My love and I have decided to buy
a microcomputer personal kit
and a semidetached software house
with bit-sliced ducks
flying up the wall
and Chinese Girl printouts
papering the entrance hall.
Through logic gates of love each night
we enter our world of Basic aout
riding along our I/O fun bus 9
holding hands with our bugs
and drinking ROM with iced coke
while you solder-iron my best dreams
and I edit your schemes
to upgrade some day
to a much bigger machine
and a man witha DP budget anda
much bigger development team.
And our database is grown pregnant
with shopping lists and babies names,
with shattered hopes and video games
even this poem’s now being writ
by the (LOGIN)
micro computer personal kit
(AND NOW HE HAS GONE
HIS LOVE WITH I
IS NO LONGERSHY.
LOGOUT)
by MALCOLM PELTU, Editor,
Bi | Computer Weekly. Version 2.3
Pet Software
From our current catalogue of over sixty titles:-
CCS Microhire
MICROCOMPUTER
Stock Control, RENTAL
Sales Analysis, SPECIALISTS
Income Tax,
Share Portfolio,
Assembler/Editor,
Line Renumber,
Peek & Poke,
Addressbook,
Super Startrek,
Backgammon,
LIFE,
Statistics,
PET Basic Tutorial.
Before you buy a micro, why not
hire it for a day or a weekend?
From £2 a day we hire out a range of
micros for evaluation/experience or
program development.
* Apple II
* Commodore Pet
* Nascom | or Micros
* Research Machines 380Z
Plus many more. If you are,a PET owner and would
like to receive copies of our monthly catalogue, send
an S.A.E. to * Tandy TRS 80
* SWTC 6800 or MSI 6800
Petsott
PO Box 9, Newbury, Berks. RGI3 IPB
Tel. 0635-201131 O1-352 1100
Telex 8951672
@ Circle No. [10
Protect your future investment.
Try out a system now.
For details write to
CCS Microhire, Freepost,
Letchworth, Herts SG64YA
Cune-Cride Lic
224 TOTTENHAM COURT ROAD, LONDON W1. TEL: 01-636 8161
For electronic calculators and
watches.
We have the largest range in
London at the most
competitive prices.
Export and Personal Export
Tax, free facilities arranged.
HEWLETT PACKARD x CASIO
* SHARP * TEXAS
INSTRUMENTS: OLIVETTI
SEIKO * SINCLAIR
COMMODORE x SANYO x
NATIONAL PANASONIC, ETC.
We Stock the
COMMODORE PET 2001-8
and
APPLE II
microcomputers with a full
range of hardware and
software options.
@ Circle No. 112
PRACTICAL COMPUTING October 1978
@ Circle No. III
Micros or
so MUCH has been written about the appli-
cations of microprocessors that it is often
forgotten that many tasks for which they
are being proposed are within the scope
of a good programmable calculator. In
fact, programmable calculators can take
over many of the functions of a computer
in, for example, a small business system,
and can represent a very cost-effective
alternative to the use of time-sharing
services.
Obviously, there will always be some
functions requiring, say, mass storage,
where the computer approach will be the
only viable one, but the programmable
calculator is expanding its range of appli-
cations all the time.
Comparison
The term ‘programmable calculator’
covers a wide range of products, ranging
in price from below the £30 mark to
about £1,700. When one is considering
calculators which can be considered as
alternatives to microcomputer systems,
however, one has to look to the more
sophisticated machines with program
steps running into hundreds or thousands,
either on magnetic cards or in pre-
programmed modules.
Some idea of the computing power ob-
tainable from a modern hand-held pro-
grammable calculator can be gained from
the table, which compares a mainframe
computer circa 1955 with a modern hand-
held programmable calculator, the TI-59.
It can be seen that, in terms of what the
modern machine can do, ‘personal com-
puting’ is now very much with us.
Professional users, small businesses and
home users all can benefit from the flex-
ible programming, computing power,
data-storage capability and high reli-
ability of the modern calculator.
It is worth looking in more detail at the
various modes of operation available to
the user with a programmable calculator
such as the TI-59.
First, the magnetic card facility can be
used for the storage of user programs and
data. Users can build their own personal
PRACTICAL COMPUTING October 1978
Calculators?
‘Programmable calculators can take over many of the functions of
|a computer in a small business system and can represent a very
cost-effective alternative to the use of time-sharing services’.
by JOHN GIBBONS
Texas Instruments Ltd.
program libraries, for example. Next, the
user can benefit from the availability of
what TI calls ‘solid state software,’ plug-
in modules containing a host of pre-
written programs stored in solid-state
ROM. Among those available are a
Master Library containing a selection of
commonly-used mathematical, statistical,
and financial routines and conversions,
as well as games and diagnostic programs.
There are also program libraries aimed
specifically at marine navigation, survey-
ing, aviation and applied statistics.
This concept has been extended recently
with the introduction of custom CROMs
(Constant Read-Only Memories) which
take the same plug-in form but which are
developed specifically where a user has a
volume requirement for a particular appli-
cation.
One enterprising company, Efficient
Computer Systems, is taking a customised
calculator plus a PCIOOB printer, adding
a CROM developed to its own specifi-
cation, and re-packaging the complete
machine as a device known as ECSTASY.
This is designed specifically to help book-
makers in calculations associated with
combinations of bets, which can be very
time-consuming using conventional
methods.
It is important to remember that all the
functions can be incorporated in what is
a hand-held machine. Even with the
addition of a thermal printer—which also
permits simple user prompting, plotting
and editing routines—the result is still a
very compact machine.
Applicability
Some idea of the applicability of pro- |
grammable calculators to tasks which |
normally would be considered the pro- '
vince of a full-scale computing system can
be gained from our own experience, as
users, within the world-wide Texas Instru- -
ments organisation. Almost 10,000 TI-59
(continued on next page)
Table I.
IBM 650
computer
TI-59
calculator
Power, KVA
166,500
transistor equivalents
17-7
Air conditioning
Memory capacity
Primary
Secondary
3,000 bits
100,000 bits
Execution time,
milliseconds
Add
Multiply
7,680 bits
40,000 bits
0-070
40
$200,000
(1955 dollars)
$299.95
(1978 dollars)
(continued from previous page)
programmable calculators are in use
within the TI organisation alone and it is
estimated that, as a result, company time-
sharing costs have been cut by around 40
percent.
In addition, of course, there are con-
siderable savings on executive time, since
they have the calculators immediately
available. Accuracy is improved, repeti-
tive operations are speeded, and pro-
grammability offers the additional bene-
fits of ‘what if?? operations and better,
quicker decisions.
Versatility
Typical application areas for this type
of programmable calculator include sales
desks—for instant pricing and order total-
ling; buyers—prices, discounts and profit
comparisons; estimators—least-cost
analysis and estimations; production
control—yield calculations and produc-
tion costs; stock control—usage forecasts,
service factors; accountants—costing,
planning, depreciation, cash flow and
taxation; actuaries—investments, yields
and prices; estate agents—investment
comparisons and return on assets; gen-
eral management—planning, decision-
making and ‘what if?’ decisions; insur-
ance—cash analyses, plan evaluations and
computer
a Dec-writer. £95 card.
Dersonal
Computers
Limited
The world’s best-selling personal
# New powerful basic and new graphics on Rom. £75 card.
* Talk to Apple with voice recognition, speaker trained, 32 word vocabulary. £165 card.
%* Colour Graphics. High resolution 280h x192v, 6 colours, easy-to-use.
16 colours, very powerful. Low resolution 40h x 48y,
* Apple's disks. Powerful DOS. 116K bytes capacity, multiple drives, fast access. £395.
* Use Apple as a computer terminal 110 or 300 BAUD. Full or half duplex or use with
% Use any 8 bit parallel printer with Apple 11.
Print up to 3,700 lines per minute. 255 character lines, upper and lower case. £100 card.
¢
... It fills the gap between
the conventional program-
mable calculator and the
personal computer .. .”
presentation; and architects—building
design, heating requirements and insula-
tion.
In addition to normal business-type
use, applications include TI-58 or TI-59
calculators being employed by hot-air
balloonists for navigational and endur-
ance computations in pursuit of a world-
record bid, sailors in The Observer Round-
Britain yacht race for navigational/speed
calculations, and as part of a training/
evaluation North Polar flight by the RAF.
The next step from this type of cal-
culator is represented by the Texas Instru-
ments SR60A, termed a ‘personal-com-
puter/calculator’ because it fills the gap
between the conventional programmable
calculator and the presently-available per-
sonal computers, which tend to be tied into
a TV-display type of presentation and
require the use of a formal programming
language.
Costing between £1,200 and £1,700,
depending on memory configuration, the
SR60A offers a combination of a highly-
intelligent calculator, a ‘question/answer’
prompting display with normal English-
RAIR
@ Circle No. 113
2S EERE ASSES i
language instructions and a quiet built-in
thermal printer.
As a result, the machine is ideally
suited to small businesses and other appli-
cations where it is likely to be used by
operators without special training in the
use of computers.
One business equipment firm, Betos
Systems of Nottingham, has developed
its own payroll program for the machine
and reckons it can save considerable sums
for any firm with more than 50 employees
in this role alone—apart from all the
other facilities managers can use.
At the bar
Another company, Abacus of Dublin,
has developed a program for calculating
bar stocks, while the organisers of the
1978 Milk Race, the Tour of Britain cycle
race, found the SR60A invaluable in pro-
viding instant printouts of the complex
points system for results at each stage of
the race.
This brief review of some aspects of the
current programmable-calculator scene
has highlighted certain aspects. Appli-
cation areas are still growing and there
are signs that the gap between program-
mable calculators and microprocessor-
based personal computers will be closed
still further in the coming menths. ia |
BLACK BOX
MICROCOMPUTER
@ Intel 8085 microprocessor
@ Dual minifloppy disk drives
@ 64K bytes RAM memory
@ Serial I/O interfaces
@ Floppy disk operating system
@ Advanced BASIC interpreter
@ Relocatable FORTRAN lV compiler
@ ANS COBOL 74 compiler
30-32 Neal Street, London WC2H 9PS
Telephone 01-836 4663, Telex 298452
@ Circle No. I14
PRACTICAL COMPUTING October 1978
COMPUTING’S FUN
WITH YOUR PET
THERE’S a school in Dorset which saved
40 tons of waste paper to buy its Pet com-
puter.
Last month 500 Pet systems were sold
in the. U.K., bringing the total to 1,500
here and 3,000 in Europe.
| There is no doubt Pet is the fastest-
selling ‘‘chome” computer of its kind in
this country and we like it.
We would not recommend you to go to
the limit of hunting around for 40 tons of
waste paper, like Queen Elizabeth’s School,
but it is certainly worth hunting for your
local Pet dealer to have a look at the
system.
The Pet was introduced to be sold to
the home computer market, so it would be
unfair, we feel, to review it from the view
of a computer professional.
We know, however, a number of large
organisations who are buying, or con-
sidering buying, Pets and, presumably,
they are not going to use them as play-
things.
According to Commodore which manu-
facturers the Pet, education and super-
calculator applications account for more
than half its sales. Business administration
and program development accounts for
about 20 percent, while the hobbyist is
about five percent:
Our Pet (price £695 inc VAT) which we
had on loan for a short time, arrived
PRACTICAL COMPUTING October 1978
WITH PETS GRAPHICD, YOU Com
DRAM FRICY SAR GRAPHR
without documentation. We received a
booklet entitled An introduction to your
new Pet which shows how to write simple
programs and how to load, but not to
save, programs.
In an appendix there is a command and
statement summary and notes on cleaning
the tape heads. There are, in fact, two
versions of the booklet; the first tells how
to investigate hardware problems and
what the interface specifications are, and
the second lists and explains the software
error messages.
Programs without
problems
Working from the booklet we wrote and
ran a number of simple programs without
problems. The display is very clear and
steady, although it is a little cluttered with
text on adjacent lines. The keyboard is a
calculator rather than a typewriter key-
board, although letters are held in the
normal QWERTY sequence.
Using a two-finger “hunt and peck”
technique the keyboard was not too un-
pleasant to use but we asked one of our
typists to try it. “Oh, my God”, she said,
“T will have to cut my nails’’. It is certainly
not possible to touch-type if you are used
to using a normal typewriter and our
typist soon adopted a two-finger techni-
que. One advantage of the keyboard is
that program entry normally does not
require the use of the shift key.
Using the cassette unit to save and load
programs was very easy. Tapes can hold
multiple named files and the LOAD com-
mand will either load the next file or
search for a named file.
We had no instructions on using the
SAVE command to dump a program to
tape but we had no problem in doing so.
Type SAVE or SAVE “‘name”’ and the
message “PRESS PLAY AND RECORD”
is displayed; press these and the program
is written to tape.
Pet responds with READY when the
program has been written. The tape we
used for saving and loading programs
was a W. H. Smith C90, which is reason- |
ably cheap. There is a note in the users’
manual which says that you should use
“good, low-noise, high-energy tape’”’ and
not “‘three-for-£1 type tapes’’.
Pet BASIC is a good extended BASIC. Features
include— ;
Integer, floating point and string variables;
A full set of scientific functions;
Logical operators;
Multistatement lines;
String functions, LEFT$, RIGHT$, MIDS$,
CHR§, VAL, STR$;
PEEK, POKE, USR, SYS to interface to mem-
ory and machine language subroutines;
Logical operators;
Time-of-day variable.
Variable names are a letter or a letter
followed by a letter or a digit. Integer
(continued on next page)
=
21
(continued from previous page)
variables have a % following the name
and strings have a $. Floating point
variables occupy seven bytes and main-
tain nine significant digits.
String variables can be up to 255
characters long. The documentation is not
very clear about integer variables; they
occupy seven bytes (the same as floating
point) but are restricted to + 32767 to
32768.
For reasons which are not explained in
the manual, integers cannot be used in
some statements. For example, FOR 1%
=1TO20 gives an error message. In
addition to simple variables, one- and twc-
dimensional arrays can be used. Each ele-
ment of a string array can contain 0 to
255 characters.
Simplified
keying
As well as the normal INPUT and
PRINT statements there is a GET state-
ment which gets a single character from
the keyboard or tape. Data on tapes can
be read or written and named files can be
specified so that a tape will be searched for
a specific file.
The PEEK and POKE statements allow
a specific memory location to be examined
or changed. The SYS function allows con-
trol to be transferred from BASIC to a
machine routine at a specified address.
Program keying is simplified by the fact
that the shift key is not required. There is a
delete key which deletes the last character
input and an insert key which allows
| characters to be entered in the middle of a
line. There isno RENUMBER command,
but a re-number program is available.
Running programs can be interrupted
with the STOP key and variable values
can be entered or displayed using imme-
~“S
diate statements. The program can then be
continued by typing CONT.
We received the following documenta-
tion:
An Introduction TO YOUR NEW PET.
There are two versions of this, both of
which have much the same introductory
and statement summary sections. They
have different information in the appen-
dices; the first has hardware notes and the
second has software error information.
We recommend you have both versions
although a re-print containing the best
of both is said to be coming shortly.
PET Computer Users’ Handbook. This is
badly-produced and difficult to use but
essential reading if you are to use the
system seriously. Try the section on using
the cassette unit for data files if you want
to get confused. CBM says the U.S. ver-
sion is worse.
PET Users’ Club Newsletter. There were
two of these, both containing useful hints,
details of errors found by other users, and
information on new hardware and soft-
ware releases.
There are also hardware and software
manuals on the MCS 6500 for people who
want to delve deeper into the machine.
There is also a tutorial tape available from
Petsoft, a company selling PET software.
A golden rule for small computer users
is “don’t buy unless the system can be
expanded”. Pet has the following hard-
ware ports-
| EEE—488 interface
8-bit user interface
2nd cassette interface—drive available now
Memory expansion inter face.
You can buy an adapter (but not from
CBM) to enable an RS 232 device (a prin-
ter) to be interfaced via the IEEE port. If
you plan to store data files on the cassettes
you will need a second drive to enable
files to be updated (reading on one drive,
and writing with the updates to the second
drive).
It is a safe bet the PET hardware and
software items will be available from a
large number of alternative sources. In the
U.K., alternative hardware, memory ex-
pansion and RS 232 adaptors is available
from R. Baily Associates.
Under development at CBM are floppy
disc printer, memory expansion and
modem.
Wide variety of
software
One of the main attractions of buying
a Pet is the software available. World-
wide, the number of independent dealers,
users and “‘publishers” of software for the
Pet is astonishing, until one realises that
the company expects to sell 35,000 Pets
this year. If it can get anywhere near its
production targets, it could well be higher.
Commodore publishes software both
developed by itself and by its users. Soft-
ware for the Pet can be obtained from two
sources—one is obviously Commodore
and its dealers and companies selling Pet,
the other is the community of Pet users.
Examples of software available from
Commodore—by no means a comprehen-
sive list:
Basic—Interactive. Written by two
college professors. Teaches you BASIC
and how to program. Fifteen chapters, six
sample programs and homework assign-
ments. Price £9.
OSERO—A game of skill offering two
levels of play against the computer.
Price £8.
Pontoon—Board game with a true 52-
card pack.
Wrap Trap—Dynamic graphics game
in which the player has to trap the com-
puter. Good arcade-quality graphics.
Price £8.
Noughts & Crosses—Exactly that.
Price £3.
Lunar Lander—Try to put your space-
ship on the moon. £8: We had great fun
with that.
Rotate—Difficult for non-experts.
Similar to little plastic trays with movable
letters and letter missing. Price £5.
Biorhythms—Find out when you are
up or down. Price £8. We seem to be
permanently down.
Commodore also has a number of
packages for business applications like
management, stock contro! and inventory
programs.
Typical of the software produced by
outside firms for the Pet is that produced
by PETSoft at 318 Fulham Road,
London, SW10. Among the software
available from that company is:
Fighter pilot—Rates your skill against
shooting down enemy pilots as_ they
streak past the cross hairs of your gun-
sight. Addictive. Price £7:50.
Alien attack—Dynamic graphics as you
(continued on next page)
PRACTICAL COMPUTING October 1978
ely
a HK) eT
(continued from previous page)
captain your own spaceship through the
galaxy thick with meteorites, space pirates
and aliens. Price £7°40.
Personality test—Fifty questions fired
at you after which the computer tells you
what you are really like. £9.
Life expectancy—Do you really want to
know? Price £5.
Chicken recipes—First of a series of
recipes. £4.
Payroll-—-For up to 100 named employ-
ees, handling bonuses, overtime and de-
ductions. Price £12.
Mortgage—Five programs covering all
aspects of mortgages. Calculates mortgage
outstanding, terms, and tax relief.
Frightening. Price £7.
Assembler—One-pass and two-pass
assemblers for Pet, full text editor and
documentation. £49.
Basic Renumber—This routine re-
numbers your Basic program from a given
number in given increments. Alters
GOSUB and GOTO to match. Auto
delete if required. £35.
Binary re-number—Line only remem-
ber, re-numbers programs from 10 in
increments of 10. These parameters may
be changed easily. Program is a binary
routine and is transparent to the user and
machine. Price £25.
PEEK & POKE—-How to use two of the
most useful Pet statements. £5.
Plus permutations and combinations,
factorials, cubic and quadratic equations,
simultateous equations, complex arith-
metic, prime factors.
Pet has the most impressive list of
dealers of any personal computer avail-
able. It includes 35 names distributed
around the country, many of them highly-
respected businesses in electronics and
computer systems. They include Memec,
Lasky and Sumlock.
Apart from what this means in terms of
locally-available sales and support, most
of the outlets see themselves eventually as
software publishers. Accordingly they
have a vested interest in making packages
good—and cheap. It would be hard to
over-stress the significance of this dealer
network. It means that the machine is
receiving a powerful boost towards the
kind of volume sales which make future
price cuts almost certain.
FLD
CONCLUSI
Disappointing keyboard.
Poor documentation, except for the
simple introduction.
Much more than a simple home com-
puter.
Very good BASIC,
Good display and graphics capability
but lower-case restricts the graphics,
Reasonable expansion capability.
Wide range of programs available and
under development.
ee 0808 @ @8
PRACTICAL COMPUTING October 1978
TECHNICAL SPECIFICATIONS
Dimensions: 165” wide by 184” deep.
14” overall height.
Weight: 44lbs
MEMORY
Random Access Memory (user memory):
8K included Expandable to 32K bytes
externally.
Read only Memory (operating system
resident in the computer): I3K bytes
8K BASIC interpreter
4K—Operating system
|K—Diagnostic routine
VIDEO DISPLAY UNIT
9” enclosed, black and white, high-resolution
CRT
1,000 character display, arranged 40 columns
by 25 lines
8 x 8 dot matrix for characters and
continuous graphics
Automatic scrolling from bottom of screen
Winking cursor with full motion control
Reverse field on all characters (white on
black or black on white)
64 standard ASCII characters; 64 graphic
characters
KEYBOARD
94” wide x 3” deep; 73 keys
All 64 ASCII characters available without
shift. Calculator style numeric key pad
All 64 graphics and reverse field characters
accessiblefrom keyboard (with shift)
Screen Control: Clear and erase
Editing: Character insertion and deletion
CASSETTE STORAGE
Fast Commodore-designed redundant-
recording scheme, assuring reliable data
recovery
Cassette drive modified by Commodore for
much higher reliability of recording and
record retention
High noise immunity, error detection, and
correction
Uses standard audio cassette tapes
Tape files, named
OPERATING SYSTEM
Machine language accessibility
File management in operating system
Cursor control, reverse field and graphics
under simple BASIC control
Cassette file management from BASIC
Pseudo random number generator
INPUT/OUTPUT
All other [/O supported through IEEE-488
instrument interface which allows for
multiple intelligent peripherals
All l/O automatically managed by operating
system software
Single character 1/O with GET command
Easy screen line-edit capability
Flexiblel/O structure allows for BASIC
expansion with intelligent peripherals
BASIC INTERPRETER
Expanded 8K BASIC; 20% faster than most
other 8K BASICS
Upward expansion from current popular
BASIC language
Strings, integers and multiple dimension
arrays
10 significant digits; floating point numbers
Direct memory access through PEEK and
POKE commands
PRICES
Pet 2001 Personal Computer: £695 inc VAT
Pet cassette deck: £59 inc VAT
Pet 2020 printer: £495 inc VAT
Typical software prices in text.
Pet users’ handbook: £5
Pet introductory booklet: £1
Pet users’ club manual: £10.
AUTHORISED COMMODORE
DEALERS
LONDON & HOME COUNTIES
C.S.S. Systems Ltd.,
502 Kingsland Road,
London, E84AE
Te . 01-254-9293
Sumlock Bondain Ltd.,
Sumlock Anita House,
15 Clerkenwell Close,
London, EC]
Tel. 01-253-2447
Petalect Ltd.,
33/35 Portugal Road,
Woking,
Surrey.
04862-69032
Central Southern Equipment,
12 Wokingham Road,
Reading, RG6 IJG
Tel. 0734-61492
NORTH WEST & NORTH WALES
Cytek (U.K.) Ltd.,
17 Exchange Hall,
Corn Exchange Building,
Manchester M4 3EY.
Tel. 061-832-7604
Rockcliff Brothers Ltd.,
Long Lane,
Aintree,
Liverpool 19
Tel. 051-521-5830
Cortex Computers Ltd.,
25-35 Edge Lane,
Liverpool 7.
Tel. 051-263-5783
D.A.M.S. (Office Eqpt.) Ltd,
30-36 Dale Street,
Liverpool 2.
Tel. 051-227-3301
Sumlock Electronic Services
(Manchester) Ltd.,
196 Deansgate,
Manchester,
M3 3WE
Tel. 06] -228-3507
Automated Business Eqpt. Ltd.,
Mersey House,
Heaton Mersey Industrial Estate,
Battersea Road,
Heaton Mersey,
Stockport,
Cheshire SK4 3EA
Tel. 061-432-4299
LONDON RETAIL
The Byte Shop,
426/428 Cranbrook Road,
Gants Hill,
Hford,
Essex.
Tel. 01-554-2177
Laskys
42 Tottenham Court Road,
London, WI.
Tel. 01-637-2232
(continued on next page)
23
24
WANTED
Good Homes for
Intelligent Pets
THE
PET 2001
Computer
£643-52 + VAT
This unbelievably versatile, compact,
portable and self-contained unit has
many varied applications and offers
tremendous benefits in the worlds of
| @ BUSINESS and COMMERCE:
! Can be used efficiently for Trend Analysis-
Stock Control - Payroll - Invoicing -
Inventory Control, etc.
@ SCIENCE and INDUSTRY:
The ‘PET’ has a comprehensive set of
scientific functions useful to scientists,
engineers and industry.
@ EDUCATION: An ideal tool for
teaching and it can be used to keep
records, exam results, attendance
figures, etc.
@ ENTERTAINMENT: Games
including Backgammon, Noughts and
Crosses, Pontoon, Black Jack and Moon
Landing.
Possesses all usual alphanumerics
PLUS 64 graphic characters for
plots, artwork, etc.
AND IN THE NEAR FUTURE
‘Floppy Disc’ data and programme
storage system and a printer, also
2nd cassette deck available.
FOR FULL DETAILS AND
DEMONSTRATION CONTACT
MR P.J. WATTS ...NOW!
PHPALEGY
(Authorised Commodore Pet Dealer)
Specialists in Electronic Servicing,
Programming, Electronic Design and
Prototype Manufacture
33 PORTUGAL ROAD, WOKING, |
SURREY GU2I SJE.
Telephone: Woking 69032/68497
@ Circle No. 118
(continued from previous page)
Euro-CalcLtd.,
224 Tottenham Court Road,
London, WI.
Tel. 01-636-8161
NORTH EAST
Currie & Maughan Calculator Serv.
5 Bewick Garth,
Mickley,
Stocksfield,
Northumberland,
NE43 7AV.
Tel. 06615-2194
Intex Datalogic Ltd.,
Eaglescliffe Industrial Estate,
Eaglescliffe,
Cleveland.
TSI6 OPN
Tel. 0642-781 193
YORKSHIRE & HUMBERSIDE
A.T.A. Management Consultants Ltd.
12 Welholme Avenue,
Grimsby,
South Humberside. Tel. 58281
Microprocessor Services Ltd.,
| Nunburnholme Avenue,
North Ferreby,
North Humberside.
Tel. 58281
Kingston Computers,
84 High Street,
Bridlington,
E. Yorks.
Tel. 0262-72837
Holdene Ltd.,
10 Blenheim Terrace,
Woodhouse Lane,
Leeds 2.
Tel. 0532-459459
MIDLANDS
Memec Systems Ltd,
Thame Park Industrial Estate,
Thame,
Oxon OX9 3RS.
Tel. 384421-3149
Taylor-Wilson Systems Ltd,
Oakfield House,
Station Road,
Dorridge,
Solihull B93 8HQ
Tel. 05645-6192
Becos Systems Ltd,
Bennett House,
155 Mansfield Road,
Nottingham NGI 3FR
Tel. 0602-48108
Davidson-Richards Ltd,
14 Duffield Road,
Derby.
Tel. 0332-266803
Arden Data Processing,
Municipal Buildings,
Charles Street,
Leicester.
Tel. 0533-22255
|
vee
| SCOTLAND j
| NORTHERN IRELAND
| Altona Road,
| Wilmslow SK9 2LT
Robox Office Eqpt.,
84 Townhead,
Kirkintillock,
Glasgow.
041-776-4388
CHANNELISLANDS
Commercial Business Systems Ltd.,
Les Forgettes,
Clos au Conte,
Castel,
Guernsey.
Tel. 0481-55574
WEST COUNTRY & SOUTH WALES
Computabits Ltd.,
4I Vincent Street,
Yeovil,
Somerset.
Tel. 0935-26522
C.S.S. Systems Ltd.,
351 Fishponds Road,
Bristol BSS 6RB
Tel. 651449
G.R. Electronics Ltd.,
80 Church Road,
Newport,
Gwent. NPT 7EH
Tel. 0633-67426
Sumlock Tabdown Ltd.,
Stirling House,
Fairfax Street,
Bristol! BSI 8HX
Tel. 0272-26683
Medical & Scientific Computer Serv.,
Lisburn,
Co. Antrim,
N.freland.
Tel. 02382-77533
SOUTHERN IRELAND
Software Development Serv. Ltd.,
84 Northumberland Road;
Ballsbridge, {
Dublin 4.
Ireland.
Tel. 683171
Specialised Technical & Control Dealers
Fairhurst Instruments,
Dean Court,
Woodford Road,
Cheshire.
Tel. 09964-25694
Datron Sales Ltd.,
Penmark House,
Woodbridge Meadows,
Guildford,
Surrey GU! IBA
Tel. 0483-37337
More dealers may have been added to the
network since we went to press. If you are
one, please let us know and we will print your
name in the next edition.
PRACTICAL COMPUTING October 1978
WIN A COMPUTER COMPETITION
To mark the launch of Practical
Computing we are giving away an
Apple II computer.
The winner of the competition
will receive a complete boxed system
including microprocessor, keyboard,
power supply, high level language
interpreter (in firmware), plus 4K
bytes of read and write memory.
You will also get game paddles
and a tape cassette machine. All you
will then have to do is connect the
system into a standard colour
Nomore than one entry may be submitted per
person. Each entry must be accompanied by an
official entry voucher.
We shall, however, accept a project entry froma
single education establishment.
Each entry must not exceed 3,000 words and
must be typed, double-spaced. Handwritten
television and it is ready to use. It
comes in a smart moulded plastic case
which you simply plug into your
mains supply.
PLUS
In addition to the computer we
shall be giving away TEN prizes of
£25 to runners up in the competition.
HOW TO ENTER
Weare looking for ideas on how
you would use the Apple II
manuscript will be accepted provided it is legible.
Closing date for the competition is October 15
1978 and entries received after that date will not
be considered.
The competition will be judged by the editorial
staff of Practical Computing. The Judges’ decision
will be final. No correspondence will be entered
Please detach and enclose with your entry
| accept the entry rules stated and agree to abide by the
judges’ decision.
Name
Company (if applicable) ;
Address
Tel No:
Signed
PRACTICAL COMPUTING October 1978
Date
computer which was reviewed in the
July/August issue of Practical
Computing.
It could be a game you have
invented. Or it could be a business
application which you have
developed. It could even be a project
which you are working on in school
or in college.
Toenter all you have to dois
write a description of not more than
3,000 words on your application. We
require a description of the
application or project plus your
solution on how you would develop
the application.
into. All entries become the copyright of Practical
Computing and entries will only be returned if a
stamped addressed envelope is provided.
Employees and relations of ECC, Practical
Computing and WHICH COMPUTER?are, of
course, excluded from entering. Winners will be
notified by post, and winning entries will be
published in future editions of Practical Computing.
Now post please to:
Practical Computing
2 Duncan Terrace
London N.1.
27
IT’S NEARER to Mayfair than Soho;
so Computer Workshop is, as the
estate agents would say, nicely situated.
So nicely situated that the initial
impression is really quite distressing by
comparison with other computer shops
—has one arrived at the wrong address?
You step into the cream-painted and
mirror-panelled entrance lobby,
casting around for some sign to con-
firm that Computer Workshop is
indeed here. All one knows is that this is
38 Dover Street, London, W1, and that
is where Computer Workshop is said to
be found.
One wades across a few acres of car-
peting and seizes a passing pin-striped
stranger with one’s steely gaze. Said
stranger pleasantly admits that he’s never
heard of it but observes that something
called South West Technical Products is
on the first floor.
On the first floor one finds it--South
West Technical Products, that is. Then, in
smaller letters, Computer Workshop. The
keen youth there reluctantly leaves the
ad
Mf
|
HOW COMPUTER
VDU and asks if he can help. One con-
siders that there isn’t really much chance
of that but asks for John Burnett, the
managing director. At last one finds what
one was looking for: and in some respects
it resembles entropy.
In a small office to one end of the main
showroom he is on the telephone. Around
him are two other people similarly en-
gaged. Around and beneath him are card-
board cartons of things without names
and printed circuit boards with the name
M6800 stamped on them. Minifloppy
discs holding data and coffee cups abound.
See what one means?
“T used to be a computer man selling
LOOKS TO GROW
bureau services,”’ proclaims Burnett. ‘‘But
I'd always wanted to start my own busi-
ness and for years I’d been trying to sort
out how to do it. To be a consulatant or
maybe to sell bureau time, but to be
independent while doing it. Looking for a
low-cost data-collection device J came
across a low-cost VDU kit. It sold for £215
without a case. You had to provide your
own TV or monitor but there was nothing
in the country like it.”
It was made by a company called South
West Technical Products and as a direct
result of the encounter in May, 1976,
Computer Workshop was formed. It was
the first computer firm of its kind in
Europe.
“T used to go around showing the VDU
kit to people, walking into expensive com-
puter showrooms and hooking it into the
cables there. It never failed to work,
though. The idea evolved from selling a
service to emulating the burgeoning micro-
computer shops in the States—although,
in the end, we didn’t exactly do that. In-
stead we became a specialist supplying
South West Technical Products goods.”
In May, 1976 Computer Workshop
turned over £2,000-worth of the VDU
kits and was based in Fulham. The ad-
dress isn’t al] that has changed.
Beating barriers
“The partner with whom IJ started is
always starting new businesses—and then
selling them. His next success was selling
camping holidays in the Mediterranean.
He likes to put his money into new ven-
tures and then finds something else to do.
“Early this year we had become the
biggest single SWTP customer in this
country so started talking about setting up
a factory here to beat freight and duty
barriers.
“During the negotiations SWTP in the
U.S. financed 50 percent of the U.K.
operations and 50 percent was financed by
Computer Workshop. In effect, Computer
Workshop was then taken over by South
West Technical Products Computer
Ltd, the holding company for the new
factory in Peterborough and the shop.”
At that point Burnett’s original partner
sold out, leaving him with a. sizeable -
chunk of the action for himself.
Today, Computer Workshop is the
retailing end of South West Technical
Products; as you would expect, it sells only
SWTP kit. ““We decided that to support a
large number of different systems would
weaken our support capability and we
(continued on next page)
PRACTICAL COMPUTING October 1978
.
Leo}
WORKSHOP
-AND GROW
(continued from -previous page)
would never get to grips with every sys-
tem. We felt it was the right decision to
concentrate on SWTP because it was the
lowest-cost manufacturer in the equipment
area and one of the largest’’.
Judging by the new premises and the
current turnover of around £75,000 per
month, he may be correct, in business
terms. But is it a shop you would want to
visit? To whom, for instance, does it sell
all its kit?
“We’re still selling right across the
field,’ says Burnett, with the exception of,
say, the hobbyist. Hobbyists in this coun-
try tend to build their own systems from
chips and other components which they
buy from large distributors. This is not
what we sell: we offer the complete thing.
Hobbyists per se represent such a small
part of our market that one can almost
discount them. Someone comes in and
says they’re going to buy them for the
home—but then they come back later and
say they’re using it in the office.”
Not a toy
If you want to know what he is selling
which makes him so unsuitable for
hobbyists you can send for a catalogue or
read any of his advertisements. Neither of
those two pieces of reading matter is very
lengthy. That is because it is all essentially
about one system which is expandable.
The SWTP processor is of course an
M6800-based device which, with twin
minifioppies, VDU and 16K of memory
will cost around £1,925. That is the price
PRACTICAL COMPUTING October 1978
ing system and BASIC compiler. It is fun
to play with but it is definitely no toy.
As an example, Burnett attaches a
bi-directional daisywheel printer (made by
Rioch and about £1,800 more) and runs
off a few impressively-personalised letters
on it. One of the packages is word pro-
cessing—‘‘but we don’t really sell it on
that,”’ he adds casually.
There is no way of looking ata cheque for
£2,000 without thinking it a lot of money
even if you get a lot for it. So how about
something cheaper? Remove the mini-
floppies and replace them with an ordinary
audio cassette recorder—that saves you
about £760. Buy it in kit form and as-
semble it yourself—that knocks off about
20 percent. Use less than 16K B RAM and
you are definitely well below £1,000.
“If you compare this to something like
the Pet or the Tandy TRS-80 which are
completely integrated units, we can’t
really compete. To build Pet-like systems
from our equipment would cost more.
But ours is more flexible and you can
-expand it as much as you like. There is no
difficulty at all; you can plug in any kind
of terminal and add any cards you
want.”
It is, in short, a system you cannot
easily outgrow. Which must be fine for
customers, included among whom are ICI,
Rolls Royce, Dunlop, Hawker Siddeley,
GEC, Marconiand ITT.
Computer workshop also has systems
installed in “many Ministry of Delence
establishments, but they never tell us what
they use it for.”’ Possibly they play Star
Wars on it; maybe something more
prosaic, like Real Wars.
“We're also getting a new type of
customer—first-time users and people who
are replacing their visual record com-
puters. And we are suddenly beginning to
attract smaller companies.”
This is something Burnett is pleased
about. Whereas most firms selling com-
puters want a few more customers like
ICI, Burnett thinks small.
Plenty of ideas
“T get people coming in who are in-
terested in writing expensive software. I
want to stamp on that sort of thing—I’m
writing ledger programs I want to sell for
£50. Fundamentally I believe that soft-
ware is overpriced but it depends on the
number of copies you expect to sell. If you
have an integrated ledger at £50 you will
have a hundred sales for it almost as a
matter of course.
“When it comes to business it is clear
that Burnett is running a lot of new ideas
and not running a charity, but in no way is
he trying to keep all of the gravy to him-
self.
““We just cannot support more than a
tiny fraction of the customers out there.
So we try to attract programmers—not
just coders but people who know business
—to install systems and in some cases
write applications software.
“As packages become available they
will probably make their money by selling
(continued on next page)
29
Shops
(continued from previous page)
hardware we will let them have at a
discount. We foresee one-man turnkey
systems houses.
“I’m beginning to develop a network of
people on this activity—the one thing that
I’m trying to instill into them all is that
very shortly they will be making their
margins from installing systems and not
from writing software,”
Some people, it seems, engulf markets
slowly and insidiously: Burnett appears to
be doing it quickly and insidiously. Con-
sider the established computer industry.
It has a ‘bible’-—the Computer Users’
Year Book—which lists every computer
installation in the country; or, at least, it
used to do. It is already missing a few
hundred installations, for Burnett’s acti-
vities seem to have gone unnoticed by the
CUYB.
Changing face
Such a standard reference source is the
CUYB that salesmen traditionally look in
jit to see who has what and by implication
who has-no computer. Burnett and his ilk
are changing that. Once the mainframe
computer manufacturers knew the exact
state of the market. Now they do not and
the situation will worsen from their point
of view as one-man systems outfits start
installing £2,000 systems for smaller and
smaller outfits.
‘The big companies are stuck with mar-
keting strategies and structures which
cannot handle unit sales at such lowcost.
They have dug their own graves and one
way they have done it is by convincing
people that the user cannot go near the
computer. Operators are trained on a
particular machine; programmers know-
ing only one language. With BASIC there
is no loyalty to any machine; it is easy to
learn; the users will no longer have to rely
on specialist programmers. The ignorance
in the established computer industry of
these things is mind-blowing”’.
At this point one quickly begins to
wonder whether the sky might not be too
low a limit to set on Computer Workshop
aims. What is coming next? Will the
machines start talking? ?
“*Yes. This machine will have a plug-in
card for £350 to give a full vocabulary of
voice output using phonetic input—it is
easier than voice input, but you never
know what is coming next.
“It is all a bit like doing a jigsaw where
you’re told where every bit goes. The only
problem is if they don’t work immediately,
you might need help. I have built all of
these kits myself and I know nothing
about electronics.”
The kind of problem which occurs if
you decide to do it yourself would be a
perfectly-assembled kit but with a solder
bridge—a piece of solder where it
shouldn’t be causing current to flow where
it shouldn’t flow. If you are justa little used
to assembling circuits on printed circuit
boards you will probably be able to spot
it. Failing that you can always take it back
to Computer Workshop.
Burnett confirms our view that the
VDU kit is an absolute sod’’ to build,
though. In fact, if help and service is on
your mind you can take out a mainten-
ance contract on your system. Computer
Field Maintenance, a well-known main-
tenance firm in the established industry,
will give you a choice of maintenance
contracts, right to guaranteeing an engin-
eer on-site within eight hours of a mal-
function.
Training courses
Perhaps your worries do not concern
the hardware so much as the concepts or
the programming. Well, Computer Work-
shop is using part of its London show-
room to run training courses. They cover
BASIC for business users; word pro-
cessing; programs for microprocessor
control] systems (for logic designers); and
the use of micros in education.
It sounds fine and surely all that is
needed is for the price to come down a
little so everyone can have one in at home?
It seems not.
“Between £2,000 and £5,000 we are in
a price range where businesses can justify
the use of systems for a much lower
volume of data or even a much more
(continued on next page)
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Edited by J.C. BOONHAM
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The main sections of the book list comprehensively the avail-
able equipment and specifications and provide references to
suppliers and distributors of hardware, software and ancillary
equipment. Every effort has been made to accommodate the
wide ranging and complex nature of the subject by introducing
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Main Contents Headings: Section 7: Available hardware;
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The above price is net in the UK only
rcle No. 120 @ Circle No. 121
PRACTICAL COMPUTING October 1978
e
9
(continued from previous page)
trivial application. Prices are failing but
| as we introduce new and more sophisti-
cated items we will stay in that price
range and the cost of existing systems will
fall accordingly.”
Burnett is after business and he knows
how much business has to spend. He also
knows exactly from where his business
is coming.
‘‘How many people,” he asks rhetoric-
| ally, ‘‘are using computers at the moment.
compared to those who aren’t using
computers? That’s where the market is.”
If you do not have a computer, Com- .
puter Workshop is thinking of you.
Only a start
Meanwhile, just off the Peterborough
by-pass, a low and featureless building
in a sickly shade of green sits in the raw
landscape of Peterborough’s new in-
dustrial estate. That is the new factory
of Southwest Technical Products (Com-
puting) Co. Ltd., the first manufacturing
operation to be set up in this country by
a U.S. micro manufacturer.
In fact, the Americans own half the
company, the balance being held by
Burnett and his partner, Hugh Woodsend.
In July, the 10,000 sq. ft. unit was
sparsely occupied. It had a staff of 26, of
whom 14 were employed on production.
The resulting output is around 150 units
a month—processors, terminals and disc
drives—equivalent to about 50 complete
systems.
This, however, is only the start. Burnett
is prepared to meet a rapid increase in
demand and intends to train up to 10
production staff a week—the forecast is
PRACTICAL COMPUTING October 1978
CT i a 510s
for 40 production staff and 12 engineers
by March, a year after the factory open-
ing.
The plant next door is also ear-
marked for takeover and with other
production tweaking this will move its
production capacity up to 400 complete
systems a month.
The ability to respond rapidly to in-
creased demand is, of course, one of the
main reasons for manufacturing in this
country: “‘Where micros are concerned,
if you do not have it on the shelf, you can
kiss the customer good-bye.”
Delays in shipments have been a big
Computer Workshop problem in the past
but Burnett reports that back orders are
down to around £40,000, compared to
£150,000 last year.
“We're beginning to get a high-speed
turnround on repairs, too,’’ he adds.
“It was chronic at one time.” There
are now engineers working full-time
on repairs in London and Peter-
borough.
The interesting and ever-growing
library of software available includes a
text editor and a system for use by
barristers. The invoicing system and pro-
duction scheduling program written for
SWTPC use are likely to be developed as
packages and a freight-handling package
is also in the pipeline.
Cosmetic aid
Given this development of software
skills, SWTPC should be able to offer the
business user an attractive package. Even
the cosmetic deficiencies of the casings
have been noted and we are assured that
their spartan functionalism will soon be
a thing of the past.
All in all, SWTPC optimism looks iike
being well-founded. The product is
already well-liked in many quarters and
has an established customer base. Product
development seems to be proceeding at a
reasonable pace.
The presence of a manufacturing
base in the U.K. will certainly be an
asset as competition strengthens—at
least until other U.S. manufacturers
follow the lead. {=
31
tt
=
<2
Pry
ri
In deepest Cornwall, a 53-year-old schoolmaster is waging a
campaign to spread the word of the microprocessor revolution to
schools in the county. The man, a self-confessed “‘bit of a nut-case’’,
is Desmond Old, head of the department of electronic engineering
and computing at Cornwall Technical College and he is in the
process of building his sixth microprocessor system for educational
purposes.
Much of his research is done in his
attic at home where he finds it ‘“‘much
more conyenient. I can leave things when
they’re half done and I don’t have to
clear up afterwards’’.
He first became interested in com-
puters in a ‘“‘serious’’ way in the early
60s when Sir Walter Puckey, a Cornish-
man on the board of ICL, decided he
would like to do something for Cornish
children.
He tried partially to finance some
form of computing facility for use at this
college and schools’, says Old, ‘‘The
immediate result was that a number of us
on the computing and technical side
attended an ICL course in London to
learn how to write programs in Fortran’.
The college came involved in computer
education in a big way in 1965, using
time on the county treasurer’s ICL 1902
computer. It was then decided to branch
out into the schools and teach computing
in a general way. College lecturers visited
the local grammar schools and gave lec-
tures in computer appreciation and, in
particular, Fortran programming.
‘We took away the programs from the
32
scholars, on coding sheets, and took
them back to college’’, explained Old.
‘‘We had a dp clerk who punched them
and they were sent to the county trea-
surer’s installation over a very early and
crude form of data link with an old ICT
70 003.”
Blocked by the
inspectorate
The situation was clearly not satis-
factory and in the early 1970s the college
tried to obtain its own mainframe but
was blocked by the inspectorate, which
“regarded us as not really big enough
users in the educational world to warrant
having a machine of our own, whether it
be stand-alone or some terminal. As a
result we were encouraged to use a
London bureau in no way associated with
the local government machine.”
That, too, was not an ideal situation
and when Old “got wind of the micro
revolution in the U.S., it opened drama-
tically what was to us a very closed door
in financial terms.”’
The first system the college built was
the Motorola D1 kit, “which got our
feet wet in the business”, says Old. ““We
then built the cheapest one which could
run Basic in kit form, the MITS 680b,
which we purchased almost two years ago.
That worked extremely well, and still
does, but it is a design which MITS has
decided not to proceed with and, as a
result, much of the extension of that
system for which we.were hoping didn’t
materialise.
“We then built the MITS 8800b which,
complete with a pair of floppy disc units
and one or two other miscellaneous
facilities, is now the main system in the
college.”’
A fair amount of software is written in
the college both in machine language and
in high-level languages such as Fortran
and principally in Basic. They also run
an in-between language used in edu-
cation, called Cesil.
That started with a form of CES.
“IBM did a version of it for us to use on
the 4360 system which was Cecil, to get
over any copyright business there might
have been,” Old said. ““We have now
implemented it ourself on micro and call
it Secil.”’ That is written in Basic for the
(continued on next page)
PRACTICAL COMPUTING October 1978
(continued from previous page)
college microprocessors, the 6800 and the
8080.
The main system applications are run-
ning programs written in either Basic or
Secil. ‘“‘We simply try to get people to
gain confidence in program writing’’,
says Old.
‘‘Where possible, we get them to enter
and run the programs themselves. Where
physically impossible, we deal with them
on a batch basis. This is not 100 percent
satisfactory but providing the teaching in
the classroom situation is well thought
out and well done, it’s not that unsatis-
factory.
Servicing noise
measurement
Some help is also given to other groups
in the college where computerisation is
applicable, such as the noise laboratory.
There thought is being given to a system
for a library for maintaining a file which
can be accessed readily for servicing
noise measurement and abatement. They
also help people with power systems and
access to data and they help to set up
their systems.
Old estimates that his work in the
college has saved aconsiderable sum. In the
last full year of using the bureau service,
they spent £6,500 on time-sharing and
the rental of terminal equipment, and
about £2,000 in telephone charges. The
bulk of that will be saved in future years
and the college is now able to use the
extra money to enter new and more ad-
vanced fields.
He estimates that he has saved £1,000
to £2,000 by using the three working
systems in the college—the MITS 680b,
8800b and the SWTP 68, which they do
not use much for “serious” data pro-
cessing.
Old believes the widespread use of
micros for small businesses is not far
away. ‘“The micro system we have is very
readily capable of performing in any dp
situation in which a small-to medium-size
business finds itself, whether it be manu-
facturing, medical practice or an office,
assuming that the work could have been
done by a bureau’, he says.
There are cost advantages and security
would play a large part in deciding to buy
a micro. “If a doctor can lock away his
disc files at night, then he will feel far
happier that he has 100 percent security.”
“In the States many medical people with
PRACTICAL COMPUTING October 1978
cee ee i
be
. ee
ss — Tie
a streak of do-it yourself have written a
tremendous amount of software to keep
patient records, If it is happened there, it
is bound to happen here’’.
Another area where he thinks micros
can be used is by small-to medium-sized
firms for payroll. “There is not much
software about at the moment”’, says Old,
“but I think if people are prepared to
write their own it wil: be a very attractive
proposition’.
Coin analysis
program
The college is writing a modular pro-
gram for payroll based on the British
fiscal method and one based on PAYE is
already running.
The approach taken by Old and his
colleagues is that of partial computerisa-
tion. If the computer breaks down, then
people can go on doing the work manu-
ally.
“We feel that many of the small busi-
ness people will gain much more con-
fidence in adopting an increased payroll
activity if they see partial computerisa-
tion agreeing with what they can check.”
They also have a program which will
deal with graduated pension reductions.
For demonstration purposes there is a
coin analysis program with which they
can work out the various denominations,
of currency as required for each pay
packet. They are now constructing the
payroll file, structuring the employee
information and the correct number of
hours he works in the day or the week.
Most of the projects originated in the
attic of Old’s home in Camborne. His
interest in electronics began with radio
and he still works in that sphere.
“T’ve always been very keen on building
(continued on next page)
33
(continued from previous page)
anything just for the sheer hell of it’,
he says. “It was through the amateur
radio journals coming from the U:S. in
the 1973-74 period that my attention was
drawn to firms like MITS and the people
bringing micros to the end-user in a very
economic way.
Attic place for
innovation
The Old attic has been the scene of
most of the innovations in use in the
college. Old is wholeheartedly backed
by his wife—affectionately known as
‘*Miss’’—and his two sons, graduate elec-
tronic engineers.
“We are continually exchanging ideas
and I am gradually getting a band of my
own staff in the college enthusiastic about
this; but it’s a question of how many
hours there are in the day and most of my
staff find there are only 24. With the co-
operation of my wife, I have managed to
find 36 and those extra 12 hours are taken
up with the microprocessing business’’.
Old has a MITS 8800b for his personal
use and has built a hybrid from what he
considers to be the most cost-effective
components available in the business. He
imported them from San Francisco and
they consist of a Morrow’s front panel
and another board, “plus a load of mem-
ory from a firm called Thinker Toys. For
something like £500 I have a very powerful
machine with an 8080 processor, 32K
memory and $100 bus.”
He is all for bringing computers to the
people, especially in education. “‘For many
years computers have been in the hands
of the wrong people’’, he says. ‘‘They are
now coming back to the engineers who
conceived them originally. ‘‘There was a
time when they were so large and so ex-
pensive that only management types
could persuade the boards of companies
to buy them. As a result, there was an
elite class looking after computers who
tried, rather successfully, to maintain a
cloak of mystique about what was going
on. Computers are now coming down to
the engineer. This is where the micro will
really take off. They will build a bridge
between the real world and the computer
world.
Fantastic future
for micros
“J think in education the micropro-
cessor has a fantastic future. One can
make learning such fun that one can now
bring about what was tried in the early
*60s with the old electromechanical ma-
chines—program arrangement. It might
be mundane things or conventional edu-
cation.
“If someone only had the courage to
Aas
employ 10, 20 or 100 unemployed gradu-
ate teachers and set up a software house
which is really well-conceived and well-
organised, there is plenty of money to be
made. If one is looking for steady employ-
ment, there is a fantastic field for pro-
ducing packages for physics or any of the
O and A level subjects where a person
can go to a computer centre and get
involved with what they want to talk
about.
No plans to
commercialise
Old has no plans to market his own
system commercially. ““Money doesn’t
interest me as long as I have enough’’,
he says. “I don’t like working to the
deadlines of the commercial world. I’m
a bit of an academic, I suppose. I do what
interests me. My two sons may wish,
when the microcomputer business settles
a little, to go out into the wide world of
business and they might tempt me to act
as some form of partner.”
He sees himself retiring within the next
year or so, even though he is still only 53.
“It’s not because I have nothing to do,”
he says. “It simply means that I can get
in contact with the other 24 hours in the
day, which I can’t at present.”
~
THE INFOTECH
DP TRAINING HANDBOOK
The comprehensive reference book for all your training
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@ how to identify training needs
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@ how to match courses with training needs
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Telephone Number.
Infotech International Limited, Nicholson House, Maidenhead,
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@ Circle No. 122
34 PRACTICAL COMPUTING October 1978
—— 86 is here today.
a In microcomputers.
now using our Intellec* “tailed lestecle system
*
17 |
and PL/M 86, an expanded version of our popular
_ PL/M high level language. And, with the ASM
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Ad intal delivers.
by Martin Collins
Until recently there were few computer
terminals, apart from the ubiquitous Tele-
type, which cost less than £1,000; and most
VDUs even today cost considerably more
than that. While one can still be charged
more than £1,500 by some manufacturers,
however, it is possible to buy a VDU for
less than £500. This article compares the
Computer Workshop CT-64 and the ACT-1
from Strumech Engineering.
The CT-64
The ACT-I
Bargain VDUs
Tue CT-64 was designed by South West
Technical Products and is being manu-
facturerd by a subsidiary in Peterborough.
The terminal is sold either in kit form or
fully assembled and can be used with a
monitor—Computer Workshop supplies a
matching monitor—or via a VHF -modu-
lator and a standard television.
Computer Workshop, like most small
system suppliers, is trying to sell assembl-
ed systems rather than kits. The people
there say that the CT-64 kit is difficult to
assemble; it takes three times ‘as long as
the SWTP processor kit based on the
M6800, so you should probably buy it in
kit form only if you have had a lot of
experience in assembling systems.
The display consists of 16 lines of 64
(or 32) characters. The full 128-code
ASCII character set can be generated and
as characters are formed by a 9 x 5 dot
matric, lower-case letters have true des-
cenders. The control characters for cursor
movement, home, page or scroll and the
like, can be defined by the user. Inverse
video is supplied for all or part of the
screen. As an option the terminal can have
two pages of memory, each holding 16
lines of 64 characters, which can be
selected on an either/or basis.
The terminal can be operated in scroll
or page mode. In scroll mode, as a new
line is displayed or entered the display
rolls up by one line and the top line is lost;
in page mode, information is entered or
displayed from the top to the bottom of
the screen. These two modes of operation,
together with the fact that all normal
cursor movements are allowed, mean that
any required screen formatting can be
performed.
Normal layout
The keyboard follows the normal
QWERTY layout with additional keys for
escape, backspace, echo, and on-line/off-
line. Additionally there is one user-defin-
able key available to anyone assembling
the kit. If a key is held down the character
repeats. The keyboard has a rather im-
precise feel to it compared to more ex-
pensive terminals.
The terminal has a standard RS 232
interface and can be configured to any
required combination of parity and stop
bits. The assembled units have an external
baud rate switch which enables the ter-
minal to be operated at 110, 150, 300, 600, |
and 1,200 baud. Computer Workshop is
also working on a modification to enable
the terminal to operate at 9,600 baud.
Kits carry a 90-day warranty, subject to
their being sensibly assembled, while the
factory-built units have a full 12-month
warranty. Maintenance can be arranged
through an independent company (CFM)
or faulty units can be returned to the
factory for repair.
At present there is a six-week lead time
on delivery of assembled units but once
full production is under way in Peter-
(continued on next page)
PRACTICAL COMPUTING October !978
(continued from previous page)
borough, Computer Workshop is planning
to be able to supply from stock.
The ACT-1 offers rather fewer features
than the CT-64. The terminal is imported
from the U.S. and is available only as an
assembled unit.
The display consists of 16 lines of 64
characters and upper- and lower-case char-
acters can be displayed. As with the CT-64,
output can be to a standard video moni-
tor or, with an optional VHF modulator,
to a standard TV set. Characters are form-
ed by a 9 x 7 dot matrix and lower-case
characters have full descenders. There is
Conclusions
@ Compared to the costs of two or three
years ago, both terminals offer good
yalue for money.
@ If you are not experienced at assembl-
ing kits and you do not want the extra
features by the CT-64, the ACT-1
scores because it is cheaper. It certainly
feels more robust than the CT-64
as well. On the other hand, the CT-64
offers plenty of features for a low price.
@ If you plan to spend a lot of time using
the VDU, it is definitely worthwhile
investing in a monitor; and the monitor
for the CT-64 is very clear. An alter-
native to buying a monitor from either
Computer Workshop or Strumech
would be to shop around for a second-
hand or re-conditioned unit, which
should cost about £60-£80,
no page mode but the screen can be
scrolled up or down. Left, right and home
are the only cursor movements allowed;
the screen formatting capability, therefore,
is more limited than on the CT-64.
The keyboard is a normal QWERTY
unit with additional keys for escape, tab,
backspace, break, rub-out and clear. The
unit appears to be more robust than the
CT-64, with a metal rather than a plastic
case and a more positive action on the
keyboard. There is an internal switch for
the baud rate and the terminal can run at
110, 300, 600, 1,200, 2,400, 9,600 and
19,200 baud.
SUMMARY
Lines per display
Characters per line
Character set
Character generation
Cursor control
Scroll mode
Page mode
Two pages
Reverse screen
Auto repeat
Data rates
Interface
PRICES
Kit
Assembled
VHF-Modulator
Monitor
7S ey] a
The terminal has a standard RS232 or
20mA current loop interface and can be
configured to any required combination of
parity and stop bits.
The terminal has a 90-day warranty and
Strumech will arrange maintenance for
terminals sold as part of a complete sys-
tem. Faulty units can be returned to
Strumech for repair. The company has
only just started to supply the ACT-1 and
at present is quoting three weeks for
delivery, but intends in time to meet orders
from stock. Strumech will also supply a
monitor if required.
I
16 16
64/32 62
128 ASCII 96 ASCII
Sa 7
Cee ih
Home, up, down, Home, left, right
left, right
Yes
Yes
Yes
Yes
Yes
110-1200
RS 232
Yes (up and down)
No
No
No
No
110-19,200
RS232/current loop
£230 —
£3|5-£347 £260
£4-50 £10
£140 £125
* 4,000 character page with 1,920 characters
viewable at any one time
* 64/96 character set
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
* Switchable transmission speeds 75—9,600 bps
(split speeds optional)
* HDX FDX (Mode! 4002) Block Mode (Model
4004)
* Dual interface—RS232C and 20 ma current loop
* 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.
PRACTICAL COMPUTING October 1978
@ Circle No. 124
39
Practical Computing
July August 1978
Wina
computer
competition
Business
Applications
How to wire
your home
The new magazine for the computer enthusiast.
Each month we shall be looking at how
computers can be used in the home, school
and as small business systems.
In The Home
You don't have to be a programmer or
computer professional to read Practical
Computing. It’s the magazine that tells you
how to get started, who to buy from, and
what you can do with computers in the
home.
There are hundreds of applications that
you can run on your own computer — and it
doesn't cost the earth.
Each month we give a practical review
of ahome computer, detailing what it can do
and how much it costs.
We look at peripherals. You can build
your own or buy them off-the-shelf. We also
look at what software is available and give
you a step-by-step guide to programming
your own system.
There's games to get you started. We
show you how to develop TV games, space
war games, puzzles, sports simulation,
music and speech synthesis and how to put
your dream games into reality.
Then there's a host of other applications
you can develop like automating your home,
sorting out your finances, mathematics, and
even how to speak to your computer.
In Business
Whether you are running a small
business or you want to develop business
applications, Practical Computing shows
you how to get started and what you can do.
Word processing, accountancy, mailing
lists, small business systems, stockbroking,
stock control, typesetting, simulations, cash
flow, payroll, surveys, bookkeeping,
graphics, and real-time control are just
some of the applications you could develop.
We show you how you can make money
out of developing and selling your computer
applications. And if you are asmall
business, we tell you about the packages
that have been developed and the costs of
buying your own system.
Each month there are articles
describing business applications in detail.
We review the equipment you need and how
much it costs.
You can save money too! Our
evaluations cover microcomputers,
terminals, peripherals, software packages,
periodicals, booklets and suppliers of
equipment. We help you choose the
computer that’s best for you — before you
spend money on one that isn't.
And in Education
We examine how computers can be
used in education. Develop timetables, learn
about programming, classroom computer
projects and games, mathematics and
business studies are some of the
applications described.
We aiso look at how other schools,
colleges and universities are using
computers along with actual project
descriptions and case studies.
Practical Computing is fun. We've got
style, colour and we're packed with lots of
ideas to help you get the most out of your
computer. Try us now.
Available from all leading newsagents
40
PRACTICAL COMPUTING October 1978
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Microprocessor repl..TMS4044 ‘25 ea. | (250ns) Static Rams 16K Dvn. Ram
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COMPUTER MAINFRAME
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8 FLOPPY DISC DRIVE. with Cabinet Power Supply +8v at 18amps
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Inctudes Cabinet, Disc Drive, Power MothenBoardle! ilaislotsawith
Supply, Cable, Fan & Data Cable. connectors Assembled & Tested
Has AC line filter. Has Whisper Quiet Fan & AC Line Filte
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Cabinet size 10°°H x 10°W x 16D . : 1 ee e
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@ Circle No. [25
PRACTICAL COMPUTING October 1978 4|
Four off-beat entrepreneurs in Surbiton are enjoying themselves
picking up old computers and making them work. And, what is
more, they’re making money at it. We visit Galdor Computing to
find the secret of their success.
3
mGALDOR came p
THE amc,
>
rms
_ ELECTRONIC
GRAVEYARD
THE ENTRANCE to Galdor Computing Ltd,
at 52 Brighton Road, Surbiton, is a nar-
row doorway sandwiched between a men’s
boutique and an _ insurance broker.
Through: it, you enter a dark passage
where there is just room to squeeze past
a tired-looking disc drive, two huge air-
conditioning units and several dusty
boxes of components. The passage leads
to what was once the back garden of
No. 52, now the Galdor computer room.
It is no ordinary computer room; at
first sight it is more like an electronic
elephant’s graveyard. Some 40 ft. square
by 9 ft. high, it is packed full of machinery
—-so full that there is barely room to move
between the grey cabinets.
Almost every known peripheral seems
to be represented. An old ICT card in-
terpreter stands in a corner; a multiplexer
nudges a graph plotter. Some cabinets
stand open to reveal half-empowelled
innards, and every flat surface is stacked
with boxes of cards, discs and tapes,
chunks of abandoned core store, man-
uals, and PCBs by the hundred.
Somewhere in the midst of all this you
should find one or more directors of
Galdor, perhaps mending a disc drive,
testing a highly-modified version of an
ICL operating system, playing Star Trek,
or running a job for a customer. For
while Galdor is a properly-constituted
limited company offering conventional
bureau services, it is not run in the same
way or with the same aims as an ordinary
computer bureau.
Natural
Perhaps the easiest way to understand
Galdor is to go back to its beginnings.
Around 1968, half-a-dozen students of
electrical engineering at Kingston Poly-
technic decided they needed more com-
puting facilities than the Poly could offer
them. It seemed the natural thing to buy
their own, so they did. London Uni-
versity was dispensing with an ICT 1301,
and they obtained it for £300, buyer to
collect. .
Finding somewhere ‘to put it was no
problem; there was plenty of room in the
back garden. It was a matter of getting
planning permission, knocking down the
existing shed, building a computer room
from the foundations, dismantling the
computer, transporting it to Surbiton,
and putting it together again. Nothing to
ite
Flippancy aside, the nonchalance with
which Galdor “staff” tackle the most
daunting projects is one of the things
which most impresses the visitor. Another
is their equal familiarity with hardware
and software. Commercial computing
tends to divide people into hardware or
software specialists, so that real all-round
knowledge has until recently been a rarity.
At Galdor it is taken for granted.
Then there were two
Of the original half-dozen, only
Andrew Keen and Stuart Fife remain.
They have been joined by Pete Singleton,
who paid a visit two years ago, decided
to stay the night, and has been there ever
since.
The three form the full-time staff of
Galdor. Another director, John Sheane,
has a job with ICL, and there are part-
time helpers who drop in whenever pos- |
sible.
After serving long and well, the ICT
1301 was replaced a little over a year ago
and is now being re-commissioned by
another enthusiast. Since then, hardware
development has been extremely rapid.
The first replacement was an ICL 1901,
which quickly showed itself to be very
short of processing power. It was soon
replaced by an ICL 1903.
That is the machine which Galdor is
now running, equipped with 32K words
of core store, six EDS8 disc drives, eight
7-track tape drives, paper tape reader and
punch, card reader and punch, and two
line printers of 600 and 1,250 lines per
minute. ; I
That, however, is by no means the end
of the story. One main reason for the con-
gestion in the computer room is the vast
bulk of a 1905E which stretches almost
the length of the room. It has a 128K
(continued on next page)
PRACTICAL COMPUTING October 1978
(continued from previous page)
store and will be equipped with the same
eight tape drives, but no fewer than 14
disc drives, three printers, a graph plotter,
a local video controller initially with three
VDUs, and a multiplexer to handle up to
10 telephone channels.
All the hardware is already there and
the process of getting it running is already
well under way. ‘‘We seem to have bitten
off a bit more than we can cope with this
time,”’ says Keen, peering over the clutter.
All the same, he is already planning the
acquisition of a second 1905 to provide
back-up, as soon as room can be found
for it.
Acquiring all that equipment has made
the members of Galdor experts at the
Steptoe game. First, they look through
the Computer Users’ Year Book to see
which firms are still running the kind of
machines in which they are interested.
Those firms are then contacted to see if
| they have anything they wish to dispose of.
High hit rate
The method produces quite a high hit
rate. ‘‘The trick then,” says Keen, ‘“‘is to
offer fractionally more than the scrap
merchant,” though often they find that
firms are sympathetic and generous once
they learn about Galdor.
The result is that much of the equip-
ment goes to them at near-giveaway
prices. One of the line printers, for ex-
ample, cost £30, and disc packs are in
plentiful supply at around 50p each.
The 1905E cost £2,000, a massive sum
by Galdor standards. Keen points out that
for around the same sum they could have
bought a modern micro with about the
same processing power, but that of
course, would have nothing like the same
capacity for handling peripherals.
Naturally enough, not all the equip-
ment acquired in this way is in perfect
working order. One or two of the tape
decks, for example, have a nasty habit of
PRACTICAL COMPUTING October 1978
Andrew Keen at the console.
Stuart Fife assists young visitors
to play Lunar Lander.
splitting tapes, and disc drives are often a
source of trouble. That is a problem which
Galdor members take in their stride and
there is very little with which they are not
capable of dealing, though there are
times when it proves simpler to replace
the faulty unit rather than track down and
cure the fault.
Financially, Galdor has always been
self-supporting. Almost from the start,
it sold machine time on the 1301. The first
customer was a friendly society which
took one and a half hours a day and the
volume has grown steadily ever since.
Today, the work includes such pro-
jects as mailing lists for clubs and
societies and a back-up service for firms
running 1900 series machines of their own.
Predictably, Galdor rates are among
the lowest in the land—at £12 an hour.
Even that may be modified and payment
in kind accepted from particularly hard-
up customers. It is characteristic that Fife
sees this as an advantage, allowing
Galdor to offer a service to organisations
which would otherwise not be able to
afford it.
The unconventional approach to com-
puting seems to affect some customers.
Users perhaps unacustomed to the idea
that computing can be fun are liable to
offer thanks for a pleasant evening by
“accidentally” leaving behind a couple of
boxes of stationery. Singleton is doing
some programming for a firm which is
test-marketing beefburgers. The ‘“‘spin-
off” from this project has considerable
effect on the diet of the resident members.
All this adds up to a method of running
a computer bureau which is unlikely to
make anyone a fortune. Turnover in 1977
was regarded as healthy at £180 a week
showing a trading profit of £40-60 a
week; not the kind of figures to set a bank
manager’s heart aglow.
Making a fortune, however, is clearly
not one of the Galdor aims. What those
aims are is less easy to define and seems to
depend largely on which of the directors
or helpers you choose to ask.
In general, the sheer pleasure of build-
ing and running a large computer system
without the normal pressures and re-
strictions of commercial life seems para-
mount. The profit motive is conspicuous
by its absence.
Playing hard
Galdor finances, while they must be a
taxman’s nightmare, are extremely simple
by normal standards. Since all workers are
either directors or paid voluntary helpers,
the firm has no employees, a fact which
eliminates effectively nearly all the bureau-
cracy involved in running a business.
While Galdor customers expect and re-
ceive professional service, its members are
relatively free to decide whether or not to
accept a particular job.
It was perhaps Singleton, who admits to
being unemployed more times than he
cares to tell, who put it best. “I decided
long ago,”’ he said, “‘that work was a dead
loss. So nowadays I don’t work—I just
play hard.”
Galdor positively welcomes visitors,
whether just to look round, to make use of
the machine, or to help. Most profes-
sional users, and possibly even more
equipment, are also welcome.
Galdor is at 52 Brighton Road, Surbiton,
Surrey. Tel: 01-399 1300. | |
43
44
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Kings Norton
Birmingham
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@ Circle No. 127
PRACTICAL COMPUTING October 1978
ULLUSTRATIRGABASIC:
( GABSIMP EE BPROL RAMMING BLARCORCL®)
THIS MONTH we
begin a series of
| articles on how to
program in Basic,
probably the most
widely-used
programming language
for small computers.
For this series we
| have secured the
serialisation rights for
; one of the best books
on the subject,
| Illustrating BASIC,
by Donald Alcock.
| Each month we
shall publish a
chapter from the book
which was specially
written for the
newcomer. Even if
you are not in that
category, it can still
teach you a great deal.
It is written with
distinct informality
and has a rather
unusual presentation;
but it is this style, we
believe, which makes
it one of the most
easy-to-read tutorials.
*
Alcock Illustrating
BASIC Chapter 1.
© Cambridge
University Press.
Reprinted by
permission.
*
Copies of ///ustrating
BASIC can be
obtained from
Practical Computing.
See the enquiry card
in this issue for details.
PRACTICAL COMPUTING October 1978
CORTEATS
Ipkatice
Ue (Somponents OF THE LANGUAGE
POSING A PROBLEM <—@ AN INTRODUCTORY EXAMPLE 2
FIRST STORE THE PROGRAM 7HEN TYPE “RUN” 4.
A KEYBOARD LIKE A TYPEWRITER?’S 5
é
vi
8
TYPING 6 SOME RULES ABOUT SPACING
LINE NUMBERS s@ THE COMPUTER SORTS THEM OUT
INSTRUCTIONS & REMARKS
STATEMENTS
NUMBERS GREAT AND SMALL i)
VARIABLES «<@ SIMPLE NUMERICAL ONES 10
REPLACEMENT OF ONE NUMBER BY ANOTHER 11
TEXTS <@ AS YOU PRINT THEM {2
TEXTUAL VARIABLES @& SIMPLE ONES a3
2 [xput & OUTPUT , EXPRESSIONS AND FUNCTIONS 15
+3) ° Sontrot
39
2, JArrays
59
a5
§ - Ldarrices
EXAMPLE PROGRAMS 104
6. ompete
Y. (Sommands
AND SIGNING ON 11f
119
8 a [ives OF DATA
©). Bonrax
LInoex
45
oF
8161 499920 ONILAdWOD WDOILDVud:
PREFACE:
gb MAKE A COMPUTER DO A CALCULATION — HOWEVER SIMPLE 6
you MUST FIRST DESCRIBE EVERY STEP OF THAT CALCULATION IN
A LANGUAGE THE COMPUTER CAN UNDERSTAND? THIS DESCRIPTION
IS CALLED A PROGRAM THIS BOOK PRESENTS A POPULAR AND
WIDELY AVAILABLE LANGUAGE CALLED 8AS/C AND EXPLAINS HOW
TO WRITE SIMPLE PROGRAMS IK IT 4
EAcrnovex MORE ELEGANT AND POWERFUL LANGUAGES ARE
FAVOURED BY PROFESSIONAL PROGRAMMERS B8AS/C 1S ADEQUATE
FOR MOST NON-PROFESSIONALS AND EXCELLENT FOR BEGINNERS o
Basic WAS BORN IN AMERICA AT DARTMOUTH COLLEGE , NEW
HAMPSHIRE , IN {964 AS A SIMPLE COMPUTER LANGUAGE FOR
BEGINNERS o 1T PROVED POPULAR AND HAS BEEN COPIED AND
EXTENDED BY MANY COMPUTER MAKERS , COLLEGES, UNIVERSITIES
AND “TIME-SHARING” SERVICES. NOW, LIKE ENGLISH, BAS/C HAS
D/JALECTS = A PROGRAM WRITTEN IN ONE 13 UNLIKELY TO WORK
ON A COMPUTER COMMITTED TO ANOTHER,
Sphere IS SOON TO BE A _ STANDARD FOR “MINIMAL BASIC” BY
THE AMERICAN NATIONAL STANDARDS INSTITUTE fT (A.N.S.L. X32), AND
“SPECIFICATION FOR STANDARD BASIC” BY BULL, FREEMAN & GARLAND
HAS BEEN PUBLISHED BY THE NATIONAL COMPUTING CENTRE, U.K.* (1973)
THESE HAVE NOY YET HAD TIME TO ENCOURAGE EVERYONE TO FALL INTO
LINE SO THE BAS/C YOU MEET WILL PROBABLY NOT BE STANDARD o
I HAVE ACCEPTED THIS AS A FACT OF LIFE 4 ANDy IN WRITING THIS BOOK,
KEPT AT MY SIDE ELEVEN MANUALS < EACH DEFINING A DIFFERENT
BASIC » FOUR OF THESE VERSIONS ARE AVAILABLE ON BIG COMPUTERS
OPERATED BY INTERNATIONAL “ TIME-SHARING” SERVICES § THE OTHER
SEVEN ON COMPUTERS RANGING FROM BIG TO “ DESK-TOP”?« FROM
THESE ELEVEN MANUALS I HAVE TRIED TO DISCOVER AND POINT OUT
WHERE BAS/CS COMMONLY DIFFER FROM ONE ANOTHER AND
RECOMMEND WAYS OF AVOIDING DEPENDENCE ON ANY ONE
PARTICULAR VERSION. 1 HAVE USED THE WORD “PORTABLE” To
DESCRIBE A BAS/C PROGRAM WRITTEN WITH INDEPENDENCE IN MIND
f& AND TREAT THE NEED FOR PORTABILITY AS AN AXIOM,
Ft ALN.S.1. X302/76-01 ISSUED FOR PUBLIC COMMENT IN JANUARY 1976
Ww REFERRED TO IN THE TEXT AS N.c.c. STANDARD BASIC ”
ILLUSTRATING BASIC PAGE 7
You DON?T HAVE TO BE A COMPUTER SCIENTIST TO READ THIS BOOK2 IT IS
FOR STUDENTS MEETING COMPUTERS FOR THE FIRST TIME 3 FOR THOSE
IN {NDUSTRY @ PARTICULARLY ENGINEERS }) WHO NEVER FORMALLY
STUDIED COMPUTING BUT WOULD LIKE TO WRITE SIMPLE COMPUTER
PROGRAMS 3 FOR MANAGERS WHO DO NOT WANT TO WRITE PROGRAMS
BUT WOULD LUKE TO KNOW MORE ABOUT A FIELD IN WHICH THEY OFTEN
HAVE TO TAKE DECISIONS 3 AND FOR THOSE WHO CAN ALREADY
WRITE IN BAS/C BUT SEEK A BROADER VIEW OF “PORTABLE ”
PROGRAMMING AND AN INTRODUCTION TO A FEW PROGRAMMERS?
TECHNIQUES LIKE “STATE TABLES” AND “LIST PROCESSING”.
SPE TEXT OF THE BOOK 1S ARRANGED FOR THE MOST PART IN’
DOUBLE-PAGE SPREADS g EACH DEALING WITH A_ SINGLE “STATEMENT”
OF THE BAS/C LANGUAGE. BECAUSE SO MANY STATEMENTS ARE
INTER DEPENDENT THIS ARRANGEMENT DEMANDS FORWARD
REFERENCES NOW AND AGAIN, BUT NOVICES TO COMPUTING MAY
IGNORE FORWARD REFERENCES FIRST TIME THROUGH THE BOOK
WITHOUT FEAR OF MISSING SOMETHING ESSENTIAL TO UNDERSTANDING
THE SUBJECT MATTER »
| RECORD MY DEEP GRATITUDE TO THREE PEOPLE WHO MADE
THIS BOOK POSSIBLE 3 MY WIFE 4 FAY, WHO SUFFERED GRASS~—
WIDOWHOOD BUT NEVER CEASED HER WARM ENCOURAGEMENT $
MY PARTNER , BRIAN SHEARING 5 WHO HAS TAUGHT ME SO MUCH ABOUT
COMPUTING AND ALLOWED ME TIME OFF WORK TO WRITE THE BOOK $3
AND CHARLES LANG WHO BELIEVED IN MY IDEAS AND PERSUADED
ME TO GIVE THEM FORM.
Edy BOOK iS INFORMAL IN LANGUAGE AND UNUSUAL IN PRESENTATION,
RATHER THAN WRITE A JUSTIFICATION ] WOULD ONLY REMARK
THAT A CAREFUL READER MIGHT DIAGNOSE A SEVERE
ASTIGMATISM IN MY EYE AND A PERSISTENT SHAKE IN MY HANDas
Gdeicare , @onald Aleck
SURREY 4 U.K. JANUARY 1977
ILLUSTRATING BASIC PAGE ]
Ly
HOW MANY POTS OF PAINT DO
YOU NEED TO PAINT THE ROOF
AND WALL OF THIS WATER TANK ?
WE COULD GO
STRAIGHT AT IT
LIKE THIS:
roof Qa, T =7x6-5*+4= 33-2
WAM ANCA, 8 = 1 K6+5x27=55/
Total area, A=7+S = 584-2
humber of pots, G=At 236 = 2-48
rounding up, “R=3
“you need 3 pots oF paint
OR WE COULD WRITE A PROGRAM (IN ENGLISH) TO SOLVE THE PROBLEM ,
———
4. REMAARK: A PROGRAM IN ENGLISH
2. THE FOLLOWING NUMBERS ARE THE DATA 6.5, 27,236
3. READ THE DATA, CALLING THEM D,H&G RESPECTIVELY
| (think of this as putting the data into litle boxes
labelled D,H&C respectively ~ see opposite page)
4. WORK OUT 3-14*D*+4 AND LET THE RESULT BE CALLED T
(é.e. put the result in a litte box /abelled T )
\ 5. WORK OUT 3.\A«D« AND LET THE RESULT BE CALLED S
6. ADD Tio S AND LET THE RESULT BE CALLED AK
7. WORK OUT A+C AND LET THE RESULT BE CALLED SG
8. ROUND G TO THE NEXT WHOLE NUMBER AND
LET THE RESULT BE CALLED R
(4€. act! 1 toG and take the integral part of rhe result)
9. PRINT "You NEED "s R ; ” Ports"
(i.e. print whatever whole number R turns out to be)
THE END
10.
THIS HAS TRE ADVANTAGE OF BEING GOOD FoR ANY SJZE OF TANK
AND PAINT POT g% YOU NEED ONLY REPLACE THE DATA ON LINE: 2,
JLLUSTRATING BASIC PAGE 2
CHAPTER | .
TRY OBEY/NG THE ENGLISH PROGRAM
OPPOSITE gS FEEL WHAT IT WOULD BE LIKE
TO BE A COMPUTER $3 DEFILE THIS PAGE BY
WRITING NUMBERS IN THE LITTLE BOXES BELOW,
wD*=4
LA THS
Asc
HERE IS THE SAME PROGRAM AGAIN ee t
COMPARE IT CAREFULLY WITH THE You NEED
ENGLISH VERSION OPPOSITE o
[
PoTs
BUT WRITTEN IN BASICe
cn
1 REM A PROGRAM IN BASic
2 DATA 6.5, 27, 236 en ae
> Re Dy © gap Manning muti
4 LET T=3.14*Dt2/4 Q power
5 LET § e3a.44speq / meaning divide
6 LET A=T+S
7 LET G#A/c
8 LET R=I1NT (G+1)
9 PRINT “You NEED"; R; "Ports"
10 END
AND THIS ,
WHEN OBEYED, WOULD PRODUCE 2
YOU NEED 3 Pors
ILLUSTRATING BASIC PAGE 3
8+
816] 4990220 DNILAAWOD IVDILDVUd
CHAPTER 4}
PREPARE YOUR PROGRAM BY TYPING
INSTRUCTIONS AT THE KEYBOARD fw
THE COMPUTER SIMPLY S7ORES THE
PROGRAM AT THIS STAGE 8
q
Be wo Rs ie g 7
_ §® DOK’ T OBEY
ACY IMCTRUECTIONS
ga = Aa =e
|
ik A-PROGRAM 1N BASIC
2 DATA 6.5, 27, 236
3°READ DBD, KH ,C
4 LET T=3.14*4Dt2/4
5 Ler S*3.44*DeH
6 LET A-T+S
7 LET GeA/e
8 LET R=INT(G+1)
9 PRINT "You NEED‘;R;"Pors”
lL ae 10 END
ae
TYPE RUN
WHICH SETS THE COMPUTER TO WORK OSEY/NG THE STORED
INSTRUCTIONS ONE AFTER THE OTHER s& IN NUMBERED SEQUENCE >
WHILST YOU RELAX o
EVENTUALLY THE COMPUTER WILL
= OBEY THE INSTRUCTION END
ane THAT MAKES IT STOP 9
YOU NEED 3 PpoTs
BEFORE YOU CAN TAKE THE FIRST STEP AND
START TYPING THE PROGRAM YOU HAVE To
y GO THROUGH THE RITUAL OF S/GM/NG ON AND
TELLING THE COMPUTER YOU WANT TO USE BAS/C,
DIFFERENT COMPUTERS (( EVEN IDENTICAL COMPUTERS RUN BY
DIFFERENT ORGANISATIONS J) OFTEN HAVE DIFFERENT WAYS oF
DOING THESE THINGS 9 SO IF YOU WANT TO TRY THE PROGRAM Now GET
SOMEONE WHO “KNOWS THE SYSTEM” TO SIGN ON FOR YOU AND CALL UP BAS/C.
“ puG” 1S COMPUTER
TH
THIS 1S A FOR A MISTAKE 2 TP
AGAINST ILLUSTRATIC
ILLUSTRATING BASIC PAGE4- \ak FMSTAKES IN PROGR
CHAPTER HT]
EVERY PROGRAM IN
BAS/C HAS TO BE
TYPED ON A KEYBOARD
ALTHOUGH POSITIONS OF LETTERS & DIGITS ARE THE SAME ON MOST
KEYBOARDS, KEYS LIKE Gay iN THE PICTURE ABOVE VARY IN
NAME, POSITION AND FUNCTION FROM ONE INSTALLATION TO ANOTHER,
Novick ALL LETTERS ARE CAPITAL LETTERS o, NOTICE ALSO THERE 1S
A KEY FOR 1 AND A KEY FOR ZERO ¢ BOTH IN THE TOP ROW Do
NEVER PRESS THE LETTERS I AND O IN THEIR PLACE o
AS ON AN ORDINARY TYPEWRITER, PRESSING AT THE SAME
TIME AS ANOTHER KEY GIVES THE
CKARACTER SHOWN ON THE UPPER HALF OF THAT KEYS
THUS (2) TOGETHER WITH for) GIVES # wee ALONE, 3,
S
THE “BACK ARROW” 4 SERVES TO DELETE THE CHARACTER ON ITS
LEFT FROM THE COMPUTER®S MEMORY 3 TWO OF THEM DELETE
THE PREVIOUS TWO CHARACTERS, AND SO ON, THUS IF YOU
TYPE PRIMP«+<+NT THEN BAS/C RECEIVES THE WORD PRINT o
REMEMBER THIS BY EXCLAIMING OA SA/FT/ WHEN YOU HIT THE
WRONG KEYo ) SOME BASICS, HOWEVER, USE AN UNDERSCORE
CHARACTER FOR THIS PURPOSE 3 PRIMP_WUWHONT.
MOST BAS/CS USE A KEY & PERHAPS “RUBOUT??} WHICH, WHEN PRESSED,
DELETES THE WHOLE OF THE LINE YOU ARE TYPING f ROM THE
COMPUTER?S MEMORYZ ANOTHER @ PERHAPS “BREAK” ) STOPS A
PROGRAM RUNNING NEN TYERTG
RETURN §OEF LINE® PRESS
FoR A WEW LINE IN BASIC PRESS RETURN then LINEFEED,
ILLUSTRATING BASIC Pace &
826} 499990 =ONLLNdWOD TWOILOVud
6r
CHAPTER fj
1F YOU INTEND TO USE BASIC
A LOT, LEARN TOUCH TYPING,
TEN FINGERS ARE FASTER AND
LESS FRUSTRATING THAN TWO o
THERE IS A LIMIT TO THE LENGTH OF A TYPED LINE g® MOST
BAS/CS ALLOW LINES UP TO 72 CHARACTERS LONG g SOME
ALLOW LONGER LINES BUT IT iS BEST TO ACCEPT A UMIT OF 720
c~
ZJOME BASICS ALLOW GREAT FREEDOM WITH THE SPACE BAR
SOME DISREGARD SPACES EXCEPT THOSE BETWEEN QUOTATION
MARKS THUS IT WOULD BE ALLOWABLE TO TYPE 3
re
8FORD=STOP |
INSTEAD OF
S FOR DP =5 TO! P |
BUT IT (S OBVIOUSLY SILLY TO OBSCURE THE MEANING OF THE
PROGRAM IN ORDER TO SAVE A FEW TAPS ON THE SPACE BARa
€ ;
cSome BASICS REFUSE TO ALLOW SPACES WITHIN THE CONTROLLING
WORDS OF THE LANGUAGE 9 THUS THE FOLLOWING WOULD BE WRONGS
Zo Ls “ee A Bac
SOME BAS/CS DEMAND AT LEAST ONE SPACE BEFORE EACH
CONTROLLING WORD,, OR AFTER !1T, OR BOTH 3
20DATA 6.5, 27, 236
80 PRINTYYoU NEED“;R;"POTS*
SOME BAS/CS REFUSE TO ACCEPT SPACES WITHIN LINE NUMBERS
BUT DO NOT OBJECT TO THEM INSIDE OTHER NUMBERS3
100 LEP A=1G0Gk.
1000 LET A=1000.0
SOME BAS/CS DO NOT ALLOW SPACES IN FRONT OF LINE NUMBERSS
os LET A-=B a,
100 LET C= DreF°+’G
GENERALLY WHEN ONZE SPACE IS ALLOWED ( OR DEMANDED) THEN
SEVERAL ARE ALLOWED 9 AND GENERALLY A SPACE [IS OPTIONAL
ON EITHER SIDE OF THESE D> (,3 % +/- = 4 >< dD
Cae
SOME BAS/CS
OBJECT TO
THESE TOO
SPACES
OPTIONAL
MERE
3
BUT NOT IN 1.5E2 (SEE PAGE 9) NOR BETWEEN > AND= (SEE PAGE 41).
Z\ prosram WHICH ACCEPTS ALL THESE RESTRICTIONS SHOULD BE
ACCEPTABLE TO ANY VERSION OF BAS/C o
ILLUSTRATING BASIC PAGE &
CHAPTER )
LEAVE GAPS
IN THEIR
SEQUENCE
THUS 3
REM A PROGRAM IN BASIC
DATA 6.5, 27, 2R6++36
READ! wD H, C
LET T=3-14*%D#2/4
THIS IS 236,
SEE PAGE 5
LET S$ =3.14*D+H
Ba FAR GS
LET G=A/C
PRINT “YOU NEED"; R; "POTS"
END
‘Ufhere IS A MISTAKE IN THIS PROGRAMe THE LAST LET WAS
FORGOTTEN g INSERTING IT JS SIMPLE 3 JUST TYPE 3
75 LET RINT (G1)
AND THE COMPUTER PUTS LINE 75 BETWEEN LINE 7O & LINE B04
IF MAKES NO DIFFERENCE JN WHAT ORDER YOU 7Y¥PE THE LINES ¢
THE COMPUTER SORTS THEM INTO ASCENDING ORDER OF LINE NUMBERo
J YOU TYPE SEVERAL LINES WITH THE S#A7E LINE NUMBER THE
COMPUTER OBLITERATES EACH PREVIOUS VERSION THUS ACCEPTING THE LINE
TYPED LAST» IF THE LINE TYPED LAST IS JUST A LINE NUMBER
WITH NOTHING AFTER IT THEN THE WHOLE LINE VAN/SHES FROM
THE COMPUTER?S MEMORY sm INCLUDING THE LINE NUMBER 9
THAT IS HOW TO DELETE UNWANTED LINES 9 THUSS
RESULTS IN THE COMPUTER REMEMBERING ONLY?
T4290 LET A=5
phe FIRST LINE NUMBER IN A PROGRAM MUST BE GREATER THAN Oo
THERE IS ALWAYS A LIMIT TO THE HIGHEST LINE NUMBER? SOME BAS/Cs
STOP AT 9999, SOIT IS BEST TO ACCEPT THIS AS THE LIMITo
THE LAST STATEMENT OF EVERY PROGRAM MUST BE3
(@o OTHER STATEMENT BLT THE LAST MAY Say END)o .
ILLUSTRATING BASIC PAGE 7
os
8261 4990290) ONILAdWOD TWOILOVud
CHAPTER qj
A BASIC PROGRAM
iS A SEQUENCE
OF NUMBERED LINES
CALLED STATEMENTS,
A STATEMENT MAY SIMPLY
STATE SOMETHING 140 DATA 1,2, 4
120 END
30 READ A,B,C
140 LET G=A*B42+C
| 50 PRINT "ANSWER IS";G
i
OR IT MAY /NSTRUCT THE
COMPUTER TO DO SOMETHING .
A COMMON SYNONYM FOR
STATEMENT '3 /NSTRUCTION 3
THE STATEMENTS THAT DO THINGS ARE EYECUTABLE INSTRUCTIONS.
THE COMPUTER FINDS OUT WHAT IS STATED OR WHAT TO DO By
LOOKING AT THE FIRST WORD? DATA,END,READ,LET etc.
OR SOMETIMES AT THE FIRST 7WO WORDS: MAT READ,
MAT PRINT ef. (( WE MEET MAT ON PAGE 76 de
BUT THERE IS AN IMPORTANT EXCEPTIONS
MAY BE OM/TTED IN MOST
VERSIONS OF BASIC o
[yo a= AeBtarc |
REM STANDS FOR REMARK o
REM STATEMENTS CAUSE NO ACTION BY THE
COMPUTER 3 YOU INCLUDE THEM TO CLARIFY
20 REM
YOUR PROGRAM,
CREM FOR
BLANK LINES
30 REM A PROGRAM TO ILLUSTRATE BASIC ?
REM FOR
BEM BELLISHMEN
7.0) REM me RR er
Ke REM FOR
\ 50 DATA 6.5, CATES 236
ae
GO REM DIAM, HEIGHT, COVERAGE _<@—=n7 Ci arity
——_
10 REM x**x WATER TANKS ***
THE EXAMPLES IN THIS BOOK DO NOT HAVE MANY “REM”
STATEMENTS BECAUSE 1! HAVE ANNOTATED PROGRAMS WITH
LITTLE ARROWS AND CLOUDS SO AS TO SAVE SPACE o
ILLUSTRATING BASIC PAGE 8
CHAPTER f}
YOU CAN TYPE
NUMBERS THREE WAYS
g@ AS INTEGERS , AS
REALS OR IN E-FORM,
INTEGER FORM
QwHOLe Numagrsy | 160 DATA 0, 2, +4, 1000, -30
REAL FORM
(DECIMAL NUMBERS)
170 DATA +0.70, 4., .6, -1.3, 987.65
E£-FORM
(EXPONENT FORM)
WHERE £ SAYSS
“ TIMES TEN TO THE oe”
190 DATA 1E3, [3-6E-4,-13.6E6,-.0136E9
i Zi 15
4 ( oe. 9)
13+6x/0 13 6x/0 0/36 x/0
= 0. 00/36 \= —/3, 600,000 = —/3600 009
E INTRODUCES AN /NTEGER SAYING HOW MANY PLACES TO SHIFT THE
DECIMAL POINT s SHIFT TO THE RIGHT IF THE INTEGER !S POSITIVE 3
OTHERWISE. LEFT o
a= SS @
E3, 13-6E1.2 , 13.6 E 2
IN THE £ FORM THERE MUST ALW, N FRO! S75
AND AN /N7EGER AFTER \T, SOME BAS/CS ALLOW SPACES WITHIN
AN £& FORM BUT IT {S BEST NOT TO HAVE THEMo
o¥3 IN SOME BAS/CS THE BIGGEST NUMBER THAT
ep CAN BE STORED IS APPROXIMATELY +1059
| ee ((S/G MEANS FAR FROM ZERO ON EITHER SIDE
SMALL MEANS CLOSE TO ZERO ON EITHER SIDE Do
OTHER BAS/CS CAN HANDLE MUCH BIGGER NUMBERS THAN £1038 3
IT DEPENDS ON THE COMPUTER’S “WORD LENGTH” AND WHETHER
THE “WORDS” ARE USED SINGLY, IN PAIRS, OR IN MULTIPLES o
BUT WO BAS/C SHOULD REFUSE TO HANDLE A NUMBER AS BIG AS
+ 100,000, 000, 000, 000, 000 , 000, 000, 000, 000, 000, 000, O0O 4
IN SOME BAS/CS THE PRECISION OF STORAGE
S=7/ AND ARITHMETIC |S BETWEEN 6 AND 7
SIGNIFICANT DECIMAL DIGITS © 987,654,321
SACSFAG WOULD BE STORED AS APPROXIMATELY 987,654, 000,
: OTHER BAS/CS OFFER MUCH HIGHER PRECISION ,
15 SIGNIFICANT FIGURES BEING TYPICAL, AGAIN IT DEPENDS ON THE
COMPUTERS “WORD LENGTH” AND HOW THE “WORDS” ARE USED.
BUT NWO BAS/C SHOULD WORK TO LESS PRECISION THAN G TO 7 SG.FIGS..
(THE VAGUENESS OF “6 To 71S BECAUSE MOST COMPUTERS USE BINARY
ARITHMETIC , NOT DECIMALs A MORE PRECISE RENDERING WOULD BE.
“24 BINARY DIGITS FOR PCSITIVE NUMBERS}; 23 FOR NEGATIVE ; OR VICE VERSA”
BUT THESE IMPLICATIONS NEED NOT BOTHER THE NOVICE TO B4S/C2)
ILLUSTRATING Basic PAGE Q
1S
8261 499990 DNILNdWOD TVOILDVUd.
ILLUSTRATING BASIC PAGE 10
CHAPTER q
THERE ARE 286
S/MPLE NUMERICAL
q VARIABLES IN
BASIC o
oe
WE SAW SOME OF THESE ON PAGE 3. THEY
6-5 ARE THE LITTLE BOXES USED TO HOLD NUMBERS,
(R height}
Eanes \ +> THE FULL 266 ARE SHOWN BELOW. iris
Fepan
USEFUL TO KEEP A LARGE-SCALE CHART LIKE THIS
AND MAKE A PHOTOCOPY FOR EACH NEW PROGRAM.
AS YOU USE EACH VARIABLE WRITE A NOTE IN (TS
Box SAYING WHAT YOU USE \T FOR.» THIS STOPS
Gtr YOU USING VARIABLES ALREADY USED FOR SOME-
rounded
THING ELSE A COMMON SOURCE OF TROUBLE sy
A lO A GL
ee
a a
ii
wo
cm
(9)
oO
&
i
©
=
o
=r
0
a
i ‘
i
S
ra
| 3) &
{|
u i
Re
E
—s
E
|
i]
SPEEA
|
|
i
fo}
i
=
n
hi
oO
=
foo
I
<
a
Qs
o
TOUT
| | | 1 | i
icc
ica a a
ica aC re
a a a
Pe ee Pee
fae RD SE a a a a
CHAPTER {J
YOU MAY USE
EACH VARIABLE
MANY TIMES 5
EPuttinG A NUMBER INTO A VARIABLE SIMPLY REPLACES THE ONE
ALREADY THERE , COMPARE THE FOLLOWING TWO PROGRAMS 3
THE FIRST iS THE ONE ON PAGE 3 WITH NEW LINE NUMBERS 2
10 REM A PROGRAM IN BASIC oi.
20 DATA 6.5, 27, 236 (aS)
| 40 LET T= 314*D12/4 <<
| 50 LET S= 3.144D*H <= }
60 LET A=T+S ae (Sinn
70 LET G=A/C =r
80 LET R=INT(G+1) ‘ined
PRINT "you NEED"; R; "“PoTs”
END
{0 REM TO ILLUSTRATE REPLACEMENT
20 DATA 6.5, 27, 236
30 READ D, H, e
e 40 LET T= 3.14" D4+2/4
50° Ler T=T+3.14*DeH
<2 1) 6 ue Te T/c
=
70° BET... ‘T= INT (144)
80 PRINT “YOU NEED"; T; "PoTs"
90 END
WHEN A PROGRAM STARTS RUNNING EVERY VARIABLE HAS SOME
INITIAL VALUE $ IT DEPENDS ON THE VERSION OF BAS/C WHAT THAT
VALUE ISo IN SOME BAS/CS IT 15 GHEE) s IN SOME IT IS
WHATEVER THE PREVIOUS PROGRAM LEFT BEHIND 3 IN OTHERS IT ISA
SPECIAL SIGNAL TO say WZAGYVAR EE SOP GHP. son tae
Fi W ING MPLETE PR RAMS
OLLO' (we) OG 10 PRINT v
20 END
YOU MIGHT GET O OR RUBBISH LIKE -123.456 OR A MESSAGE
FROM THE COMPUTER TO SAY IT CANNOT GO ON BECAUSE VARIABLE
ya, V \S NOT SET WHEN FIRST USED o
RELY ON ANY VARIABLE BEING ZERO WHEN THE
PROGRAM STARTS 3 SET IT FIRST 3
ILLUSTRATING BASIC PAGE 11
ts
826] 4999990) DNILNdWOD WOILDVud
ILLUSTRATING BASIC PAGE 12
CHAPTER
i BASIC CAN HANDLE WORDS AS
WELL AS NUMBERS o
WE SAW THIS ON PAGE 4 o
9 PRINT "YOU NEED"; R; "POTS"
10 END
RUN
You NEED 3 POTS
ee ee eee
THE “YOU NEED" AND THE “POTS” ARE CALLED 7EY7S IN THIS
BOOK g OTHER TERMS IN THE JARGON ARE3 S7R/NG3 LITERAL STRINGS
ALPHAMER/C STRING; ALPHAMER/C LITERAL 3 AND THERE MAY BE MORE ,
Vexts ARE WORDS OR SENTENCES OR ARRANGEMENTS OF CHARACTERS
ENCLOSED IN QUOTATION MARKS, BY THIS DEFINITION YOU CAN?T
HAVE A TEXT CONTAINING QUOTATION MARKS BECAUSE THE COMPUTER
WODLD THINK THEY MARKED THE END OF IT$ BUT YOU CAN HAVE
APOSTROPHES IN TEXTS 3
| 20 PRINT "1iT’S EASY" |
ei
HOWEVER, SOME BAS/CS ALLOW TEXTS TO BE ENCLOSED BETWEEN
APOSTROPHES AS AN OPTION$ SUCH TEXTS MAY HAVE QUOTATION
MARKS IN THEM BUT NOT APOSTROPHESa OTHER BAS/CS GET
ROUND THE PROBLEM BY IREATING A PAIR OF QUOTATION MARKS
INSIDE A TEXT AS SIGNIFYING A SINGLE QUOTATION MARK 3
30 PRINT “SHE SAID ""OOH!""" ‘|
anette eset
SHE SAID “OOH!”
I a nl
BUT !T {5 BEST TO AVOID HAVING QUOTATION MARKS IN TEXTS o
PRODUCES &
Semicorons IN THE “PRINT” STATEMENT MAKE THE COMPUTER
ABUT THE THINGS TO BE PRINTED ONE AGAINST THE OTHER$ COMMAS
WOULD MAKE THE COMPUTER SPREAD THEM OUT ACROSS THE PAGE.
ALL THIS IS EXPLAINED FROM PAGE 28 ON, WHERE THE “ PRINT ®
STATEMENT IS EXPLAINED IN DETAIL.
TEXTS IN THE “ PRINT’ STATEMENT MAY BE OF ANY LENGTH THAT WILL
FIT THE LINE BEING TYPED. IF YOU WANT SOMETHING PRINTED RIGHT
ACROSS THE OUTPUT PAGE YOU MUST PRINT TWO OR MORE TEXTS§
ALL BUT THE LAST HAVING A SEMICOLON AFTER THEMo
Ie) BRU Ssec<aasscca SSS eee wk
LJ ”
180 PRINT "-----~-~-----------------
120, PRN jose ge Seg cea
CHAPTER U
Ay ADDITION To THE 286 LITTLE BOXES FOR STORING NUMBERS THERE
ARE AT LEAST 26 FOR STORING TEXTS3 THESE ARE CALLED 7EXTUAL
VAR/ABLES 4 WE HAVE COINED THIS TERM TO BALANCE WUMERICAL VARIABLE
BUT OTHER TERMS IN THE JARGON ARE 3 TEXT VAR/ABLE, STRING
VARIABLE & LITERAL VARIABLE Q
[very BASIC HAS A LIMIT TO THE LENGTH OF TEXT THAT CAN BE
STORED IN A TEXTUAL VARIABLE3 SOME ALLOW AS MANY AS 4095
CHARACTERS 3 OTHERS AS FEW AS 18 = A MAXIMUM FOR “ PORTABILITY "o
123486789 On 2h IS wT 123456739 BM UH IT
SOME BAS/CS
HAVE 286
TEXTUAL
VARIABLES
Ag , AO$,
Ai$, A2s,
etc. to
28, Z9$.
WHEN THE PROGRAM STARTS, TEXTUAL VARIABLES MAY CONTAIN BLANKS;
OR TEXIS LEFT OVER FROM A PREVIOUS PROGRAM OR SPECIAL SIGNALS
TO SAY VARIABLE UNSETe AS WITH NUMERICAL VARIABLES @PAGE 10)
IT DEPENDS ON THE BAS/C BEING USEDs SET VARIABLES BEFORE
READING FROM THEM IF YOU WANT TO WRITE A “PORTABLE” PROGRAM,
TPeXTUAL VARIABLES MAY BE SET BY “LET” STATEMENTS $
10 LET W$ = 4 ore
20 LET Z¢= “ONLY 18 CHARACTERS STORED"
ee Oke inna aaae
AND PRINTED USING “PRINT” STATEMENTS 3
30 PRINT W$3Z$3 WH
40 END
RUN
xxx ONLY 18 CHARACTERS *+*
TEXTUAL VARIABLES MAY ALSO BE SET BY “READ” @PAGE 16) AND BY
“INPUT” (PAGE 18). THEY MAY BE COMPARED BY “IF"( PAGE 4! Do
SO Iy I$=> YES" THEN 8&0
GO IF I¢= W$ THEN 8000
“oe
—
Limit TO FIT
INTO TEXTUAL
VARIABLE
ILLUSTRATING BASIC PAGE 13
BOOK
REVIEWS
The BASIC book business is hotly contested. Preparing for this
review, we found more than a dozen widely-available texts
from a variety of publishers, ranging from hobby computer
firms to conventional hard-back houses. Among computer
languages, Basic is relatively easy to learn; it is also widely
available. It will almost certainly be one of the languages,
probably the only one, offered with any small system you
consider.
We used two reviewers; one was an experienced computer
user, consultant and teacher of dp concepts, the other a
newcomer, with a very recent low-level introduction to the
subject of computing. The books we chose illustrate the
several different styles available to the Basic book writer;
there are many other titles, of course, and we would be glad
to hear of any personal preferences from readers.
| ELEMENTS OF BASIC
by R. Lewis and B. H. Blakeley
published by NCC Publications Ltd, 1972
cloth cover: A4
price £3.
IN SUCH a competitive market, there are a
number of ways of selling a book. You
might commission a well-known author
from another field. You might be a well-
known publisher yourself. Or you can rely
on gimmicks.
The NCC Elements of BASIC falls into
the second category. One could reason-
ably expect it to sell a large number of
copies simply because it is published by
the National Computing Centre. The
book is fairly conventional, an A4 paper-
back, with the slight difference that it is
laid out sideways, giving two columns to
a page.
Simple in approach
In some places, the format is used to
good effect—for example, by listing a
program in the right-hand column with
the accompanying text in the left. It
might have been advantageous further to
exploit this feature.
Its introduction proclaims that “‘a great
deal of attention has been given to its
design so that it can be used as part ofa
course in computing at secondary school
level’’. The book is essentially simple in
approach and could be of use for self-
teaching; this is helped by the extensive
use of flowcharts for sample programs.
Similarly, the authors try to adopt a
friendly stance, involving much use of the
personal pronoun. ‘Some BASIC systems
PRACTICAL COMPUTING October 1978
require us to reserve space... we have
seen that ... you may have tackled prob-
lem Ic. 3 earlier .....”’.
As a Style of English, this is frequently
condescending and occasionally irritating.
Neither characteristic improves the appeal
or the lucidity of the book.
How about this? “If it is desired to
have the numbers printed in descending
order, you may change statement
140 ...”. What the writer means by this
confusion of the personal and impersonal
Elements of
BASIC
is something like “if you want the num-
bers printed in descending order...’’.
The book is also misleading at times.
“Statements are stored in the computer
at specific addresses (their statement
number) ...’’. Well, the first part of this
is self-evident; and statement numbers do
not relate to specific addresses.
Elsewhere there is the instruction LET
A=A-+2 with the comment ‘“‘notice that
‘2’ is not contained in a storage location
but is generated by the computer when
required’’. By this the authors mean that
‘2’ is not a variable and it is not an ad-
dress; their phrasing, however, leaves
plenty of room for confusion.
Similarly, there are points which pass
unexplained. On string-handling, the book
states correctly that BASIC imposes a
limit on the number of characters allowed
in a string; it then says that “we shall
restrict ourselves to 40 characters’’ with
no explanation of this, apparently, arbi-
trary limitation.
Likely to confuse
In fact, the maximum number of
characters in a string differs from one
implementation of the BASIC language
to another. Some allow as many as 4,096
characters, others as few as 18. Alcock’s
book points out that if you adopt 18 as
the upper limit, you will be learning a use
of character string which will apply to any
BASIC.
The 40-character restriction would be
acceptable, if explained, provided the
authors concentrated on the same system
throughout the book. Unfortunately, that
is not the case. One chapter states speci-
fically that all the programs in it were run
on different computers; at best, that is
likely to lead to confusion.
Also likely to confuse are statements
like ‘‘on the system used to run the pro-
gram, a # is printed for a%".In a book
which seems to have had a fairly expen-
sive production, it would have needed
little effort to edit the program so that the
student was not required to remember
the alteration.
The book uses program listing taken
directly from the computer printout. This
(continued on next page)
55
(continued from previous page)
has two real advantages. First, it is clear
precisely what that unspecified computer
does when running the BASIC program;
and, second, it breaks up the text in an
interesting way.
To fit the page format, however, the
listings are reduced in size—and the
quality of the reproduction is not always
of the best, which again makes them diffi-
cult to read.
There are several relatively minor
points on which the book may be criti-
cised but there are also some very helpful
features which should be commended.
For example, indenting is often used in
the program listing examples to empha-
sise the program structure—but sadly not
in all the examples.
The tricky question of file handling,
which can vary dramatically from one
BASIC to another, is dealt with by a
chapter covering ‘“‘the main ideas, prob-
lems and flowcharts’’, while some specific
BASIC implementations are treated in an
appendix. The authors picked six simple
file handling programs and show how
they are coded in nine different
BASICS.
Could be updated
Only two of those can legitimately be
described as minicomputers—the HP
2000 and CTL Modular One—and both
machines have now been superceded by
newer models. The other implementations
are on two time-sharing services (IBM
and Honeywell), two ICL mainframes
(1900 and System 4), one deleted system
(Xerox Sigma), the Burroughs B700 (now
virtually displaced by the newer B800),
and the DECsystem-10.
As illustrations of alternative BASICs,
this multiple-machine appendix is in-
teresting, particularly as the authors’
annotations are useful and to the point,
but the computer business moves quickly,
and this book dates from 1972. Some
more up-to-date examples might be more
valid.
| CONCLUSION
@ Overall we found the book competent
but boring, generally worthy but often
patronising, concerned to make the
instruction comprehensive rather than
effective.
INTERACTIVE COMPUTING
WITH BASIC - A FIRST COURSE
by Donald M. Munro
published by Edward Arnold Ltd, 1974
paperback: A4
price £3-25
ANOTHER fairly conventional book.
Designed originally for use by electrical
engineering students at Imperial College,
London, it has a very strong mathe-—
matical bias to its examples.
They show the power of the language |
56
Interactive Computing with
BASIC
A First Course
Donald M. Monro
BASIE
but it will deter many people. The sections
on matrix operations are particularly im-
penetrable, and some readers would not
wish to be able to solve the Laplace
equation in BASIC. A lack of interest in
the examples might well be reflected in
the reader's attitude to BASIC itself.
That is a pity, since the book, in
general, shows much evidence of thought
and care in its preparation—for a start,
there is a really handy list of BASIC
statements inside the front covers and the
language is summarised in a useful ap-
pendix.
Style is terse
It was never written for business users
and. for them its inappropriateness is
made more certain by the absence of a
description of some language features
which would be of particular use to such
people.
The most important omission is some
coverage of file handling—although the
book deals with the use of a READ state-
ment from DATA within the program.
Similarly, little attention is paid to fea-
tures of the BASIC system as opposed to
those of the language. The general style is
terse and the approach of the book
definitely displays its origins. We cannot
comment on its suitability as a textbook
for scientifically-orientated undergrad-
uates, which is undoubtedly its chief aim
but we could not recommend it as an
introduction to BASIC or a _ self-
instruction text for business users.
CONCLUSION
@ Conventional, competent, probably a
good textbook for anyone who re-
quires to learn the language for solving
problems with a mathematical bias,
but not for the small business system
buyer.
INSTANT BASIC
by Jerald R. Brown
published by Dymax Inc, 1977
paperback; quarto
price £4-95 (from LP Enterprises Ltd)
FROM the dustjacket blurb: ‘“‘For the
microcomputer enthusiast or the user of
the Digital BASIC-Plus language, there is
finally a book to teach you BASIC. No
longer will you have to struggle through
the reference manual provided with your
computer.
“The author has a quiet writing style
which slowly introduces new ideas in a
pleasant, non-mathematical context. To
offset this style of writing, he has used the
zaniest, wildest graphics available, mak-
ing the book a barrel of fun to read.
INSTANT BASIC is a “‘active participa-
tion” workbook. The book is designed to
use with your home computer readily
available so you can do it!
“You'll like this book. It’s designed for
beginners, covers most of the language
and is fun to use”’.
Well, that is a matter of opinion. This
book derives directly from the home of the
hobby microcomputer, California; and
its publishers have links with one of the
pioneering propagandist organisations
there, the People’s Computer Company—
incidentially, the PCC monthly magazine
People’s Computing is required reading for
small-computer enthusiasts.
—_e
Welcome change
Dymax publishes a number of titles in
the general area—like Games with the
pocket calculator—excellent for school
kids—and Your Home Computer—one of
the calmest and sanest introductions to
minicomputers we have seen, and highly
recommended for the complete novice.
Dymax also publishes My Computer
Likes Me (when I speak in BASIC). This is
a conversational introduction to the
language, a book of only 64 pages which
is effective propaganda for BASIC and has
no aspirations to be a textbook. Instant |
BASIC has aspiration to spare.
As the blurb indicates, this is a book
written specifically for two really popular
BASICs—the Digital RSTS/E implement-
ation for the PDP-11, BASIC -Plus, and
the very similar MITS/Altair BASIC
offered on the 8080A-based microcompu-
ters sold here by Compelec.
This is a welcome change in orientation
from other textbooks, most of which
seem to have been written by authors with
experience only of large-machine, time-
sharing BASICs.
The book definitely avoids a mathemat-
ical bias, which is also good, but there our
enthusiasm ends.
Instant BASIC is produced in that
irritating, late-1960s style which encour-
ages the designer to go wild with the
Letraset catalogue. The text is sober
enough but it is surrounded by a real
(continued on next page)
PRACTICAL COMPUTING October 1978
PEA 1
(continued from previous page)
welter of graphics—fancy borders, illus-
trations, line drawings and a variety of
aggressive typefaces.
That approach does not work. It does
not serve to break up the text in an inter-
FREEZE-DRIED COMPUTER PROGRAMMING IN
.22.3 Kaka KKK KKK
RG the aaiviet Student, or
Compleat Novice. Learn the
BEW streamlined ALTAIR"
style B-A-8-I-C used in
personal computers + and the
similar DEC BASIC-PLUS
esting and attractive manner, it does not
make the book “fun to read” and it
certainly does not make it easy to use.
In fact, Instant BASIC is not as bad as
it sounds. It covers most of BASIC and it
does so quite accurately—we found no
obvious flaws in the text. It is aimed
squarely at the novice—it even tells you in
quite banal detail how to use a keyboard—
and it applies to small computers; both
attributes separate this book from many
others.
In our view, though, the design and
presentation of Instant BASIC are a
serious misjudgment, and that title should
not be taken too literally—the book has
158 pages, each of which must be read.
CONCLUSION
| @ Good try in terms of ambitions, an
explicit and sometimes simply mono-
tonous rendition of the Altair and
Digital versions of BASIC, an irritating
and ultimately unreadable presentation
if you do not share its ideas on humour
and style.
ILLUSTRATING BASIC
by Donald Alcock
published by Cambridge University Press,
1977
paperback, A5
price £1-50 (hardback at £4:95)
WE LEFT the best until last. This book also
adopts a somewhat gimmicky style—it is
handwritten throughout, including the
printout examples. On the other hand, this
imparts an appealing quirkiness rather
than the offensive self-congratulation
which might have ensued.
Alcock’s introduction does not seek to
explain the absence of type-setting but it
indicates a dry wit we liked: ‘‘My book is
informal in language and unusual in
PRACTICAL COMPUTING October 1978
presentation. Rather than write a justi-
fication I would remark only that a careful
reader might diagnose a severe astigma-
tism in my eye and a persistent shake in
my hand’’.
Practical Computing readers may
already have deduced that the reviewers
liked this book. Itshould be said, however,
that handwriting can be tiring if you read
much of it at a time—that might not be
very likely, of course; and at least one of
us took issue with Alcock’s idiosyncratic
hyphens—larger than the average printed
dash, resembling a somewhat tipsy slug,
and casting a fat shadow.
The pen, however, also gives the ability
to use more graphic means of representing
concepts than is usually the case. For
example, a bug appears in text like a cross
between a ladybird and an untidy spider—
very effective.
The book is written at a fairly intro-
ductory level. As such it is clearly appro-
priate for the novice but it seems unlikely
to satisfy one category at which it is
apparently aimed, namely those that are
already able to program reasonably well
in Basic and who need a reference work.
Nevertheless, even such people would
gain some useful information about the
language from this book, though an alter-
native like the NCC one might make a
better reference textbook.
Dialect problem
From the start the author makes the
point that there are many versions of the
BASIC language and that they are notice-
ably different. He says “I have accepted
this as a fact of life and, in writing this
book, kept at my side manuals, each
defining a different BASIC’’.
Discussing the language function, he
has attempted to show the differences
between dialects; this might result in the
reader knowing all the differences be-
tween various dialects, while being unable
to program in any one of them. An alter-
native approach might have been to con-
centrate on one version, perhaps pointing
out the various. differences in an
appendix.
What Alcock does, in fact, is to present
a truly portable BASIC as far as he can. In
particular, where there are differences in
scope he will pick the interpretation
which covers most of the options. For
instance, as we noted earlier there is con-
siderable variety in just how many
characters you can have in a String.
Illustrating BASIC points out that if you
assume 18 is the maximum, you will be
writing BASIC programs with text strings
which should run on most machines.
There are few technical errors in the
text and we had to search to find any
inadequate statements. Here is one,
though: “In some BASICs, the biggest
number which can be stored is approxi-
mately +1038”. This is meaningless un-
less related to the word size of the
computer.
More generally, we are slightly suspic-
ious of the scientific/engineering bias in
some of the application examples. True,
the deflection of a diving board with a
diver on it is followed immediately by a
mortgage loan calculation; and GOSUB
is illustrated both by finding “the highest
common factor of two numbers by
Euclid’s method” and by a neat little
Mastermind-type game called ‘Moo’—
we know it as ‘Cows and Bulls’.
And, after all, the majority of BASIC
users are probably outside the commer-
cial field in any case. Alcock should not be
(Aen Ee care )
criticised for attempting to satisfy every-
one if he succeeds—-and, by and large, he
does.
Arrays and matrices are probably the
most difficult aspect of BASIC for the
novice business system user to grasp.
Alcock gives plenty or description on
arrays without saying what difference
there is between an element in an array
and a ‘simple’ variable. That is not too
bad, in fact—the relationship becomes
clearer with practice.
Matrix algebra can, however, become
tricky. As Alcock says, “In BASIC a
matrix is simply a rectangular array of
subscripted variables... Don’t run away
—you don’t have to know matrix algebra
to find MAT statements useful’’. In
principle he is right, and his treatment of
this area is as lucid as any we have seen.
On the other hand, MAT arithmetic
and knowledge of matrices in general are
by no means essential to writing business-
orientated programs.
It is refreshing to find 4 BASIC text
which takes this much care over the needs
of readers, rather than stopping short at
the nature of the language.
CONCLUSION
@ Humane, interesting, comprehensive,
and—in paperback form, at least—
excellent value for money. Congratula-
tions to the author. Very highly
recommended. i
57
Hop on a Nasbus
to 32K of memory now
The Nascom — 1 is designed with expansion in
mind. This is made possible by using the best
products available. The Z80 microprocessor
incorporated in the basic system is so
powerful it can support 64K bytes of memory
and 256 ports. To utilize this capability, we
have designed the buffered 77 — way Nasbus.
With this arrangement, the way is clear for
considerable expansion, starting with our new
memory expansion board. It has 16 memory
sockets and two EPROM sockets. Therefore,
you can fill it with 4K dynamic RAM up toa
maximum 8K or with 16K dynamic RAM up
toa maximum of 32K. A 2K Tiny BASIC in
EPROM has been developed for the board.
To go with the board, we have produced a very
flexible 1.0 board with three PIOs each giving
two, 8bit ports, plus a UART for serial
interface.
As you start building up your Nascom system
you will need a convenient means of storing
boards. Our new, custom-designed, Vero frame
will allow for a Nascom — 1 to link through a
buffer board to a 77-way Motherboard. There
Stop press...
Microcomputer Seminar
Nascom Microcomputer’s highly successful seminar is coming
to Bristol. The programme will be similar to London and
Manchester, both of which were sold out. The day includes
five lectures, demonstrations and an open forum. Venue is
the Dragonara Hotel, Bristol, Saturday, October 14th,
09.50 to 17.30.
Admission: £4.50 (inc. VAT). Lunch will be available at
£4.00 (inc. VAT) per head if there is sufficient demand.
Nascom Distributors Henry’s Radio, London W2
Camera Centre, Barrow-in-Furness, Cumbria Lock Distribution, Oldham, Lancs
Crystal Electronics, Torquay, Devon
Electrovalue, Egham & Manchester
Eley Electronics, Glenfield, Leicester
Microdigital, Liverpoo! L2
Teleplay, New Barnet, Herts
Nascom Microcomputers
Lynx Electronics, Chesham, Bucks
is then the option of eight or more expansion
boards. To power this capability there is a
new 8.5 amp power supply especially designed
for the frame.
No other system offers so much at such a low
cost. And it all starts with the basic Nascom —
1 kit which for just £197.50 offers an
intelligently usable system with video and
cassette interface, a full alpha-numeric
keyboard and a mighty CPU chip. So if you
want the best — make it a Nascom system.
Nascom-1 Kit still only
£197.50 +VAT
Please send me:
Add VAT at 8% to all above prices. (P+P not inc.)
£4.50 each
r
|
(]
|
: eaacessaseseat Buffer Board Kit/s at £25.00 each
PRRs AK RAM Board/s at £70.00 each
: eisai nee? 16K RAM Board/s at £179.00 each
/ neseueeamesnone 4K RAM (4027) at £35.00 each
' sessssesgseeeeee TOK RAM (4116) at £106.00 each
' ap eee eres Tiny BASIC/s at £25.00 each
q Nascom—1 Kit/s at £197.50 each
’ 3 2.2A power supply/ies at £24.50 each
i]
|
Se osaccveevareps Bristol Seminar Tickets at
| am/am not interested in a frame for my Nascom—1.
| enclose a cheque/P.O. for £ .......ccccseceeesees made
payable to Nascom Microcomputers, 92 Broad
Street, Chesham, Bucks. Tel: (02405) 75151
Name
Address
Se se eee een ae se eee se
@ Circle No. 132
PRACTICAL COMPUTING October 1978
Computabits em
TAKING THE CHORE
OUT OF VAT
Probably one of the most disliked and time-consuming of the statu-
tory chores imposed on businessmen is the calculation of Value
Added Tax returns. Accounting for VAT was thus a natural applic-
ation for one of the low-cost, microprocessor-based computers. A
computer will not abolish the amount of work but it will reduce it
substantially, with the bonus of increased accuracy and clarity of
records. |
This is the first of two articles which will contain a complete suite
of programs written to handle VAT accounting. They are written
in TDL Basic but can, with minor modifications, be run with most
versions of Basic available on small computers.
BEFORE discussing the design and use of
these programs it is necessary to point
out that they have certain limitations
which all potential users must bear in
mind. The most important is that they
have not been cleared by Customs and
Excise as a computerised VAT system.
By virtue of the audit trails and trans-
action listings produced on hard copy,
however, they do not have to be author-
ised; they represent one method among
many for accounting for VAT. The sec-
ond limitation is that although the system
can handle credit notes, imports and ex-
ports, as well as normal sales and pur-
chases, it has not been designed to cope
with any of the retailers’ VAT schemes.
Time-consuming
The author’s business deals with retail
sales of microcomputer equipment,
mainly complete systems. Therefore some
method of recording the appropriate
details was needed, namely tax point date;
some method of identifying the trans-
action back to the invoice; an indicator to
signify whether to add, delete or change
the record in question; the type of trans-
action—sale, purchase, import; the VAT
rate applicable; the values involved—
VAT, gross & nett value; some indicator
as to the VAT return classification.
As I do not participate in one of the
retailers’ VAT schemes, I needed only to
by
| GEOFF LYNCH |
account for VAT on a transaction-by-
transaction basis, with some method of
reading all the records for a chosen VAT
period and deriving the figures required
for my VAT return—probably the most
time-consuming part of VAT accounting.
Before you can claim VAT relief on a
purchase you need to be registered; the
purchase must be wholly as a result of
your business needs; and the supplier’s
Welcome to Computabits
Practical Computing is pleased to announce that it has acquired the publication
Computabits. It will be run each month in a special section and will continue to
be edited by Nick Hampshire.
Existing subscribers to Computabits will now receive Practical Computing
each month at no extra charge.
The style of Computabits will continue. “It is a forum to deal with the need for
exchanging information in the rapidly-expanding field of microcomputers”,
says Hampshire. “I am confident that Practical Computing will meet this
requirement and I am enthusiastic and optimistic about the new opportunities
available to Computabits as a result of its incorporation”.
PRACTICAL COMPUTING October 1978
invoice must show the minimum of infor-
mation as required by law.
The system does not hold all this infor-
mation on the computer, as the key to
the system is a number held on the VAT
transaction record and written on the
original invoice. Thus an audit trail
exists, both forwards from the original,
into the system, and backwards from the
system to the original documents.
The programs listed in this article are
written in a pre-release version of TDL
Disc Basic for use under the Digital
Research operating system CP/M on Z80
systems. The minimum requirements are
the provision of an operating system and
Basic which allows sequential disc file
accessing of up to three files at once,
console device, a list device and memory
sufficient to allow an internal memory
sort of the largest transaction file you will
ever create in one run.
Minimum of change
To use these listings with the minimum
of change a good extended Basic will
be required—North Star, Microsoft,
Cromemco. I use a Lear Siegler ADM-3A, .
PerSCI dual discs running under CP/M,
48K of memory, and an old Teletype
model 33 as the list device.
The current system has no automatic
control of file versions, although this
would be relatively easy to add. You are
required to keep a log of which files are
what. Also, due to my business being
relatively small in terms of individual
transaction value, no single transaction
with a gross value larger then £9,999-99
(continued on next page)
59
You can advertise your shops, products
and services in our Shop Window
columns for only £6 per single column
centimetre (minimum 5cm), For details,
contact:
Wim Hoeksma,
2 Duncan Terrace,
Tel: 01-278 9517
Practical Computing,
London, NI.
AUTHORISED PET DEALERS
IN MANCHESTER
Computerising isa big step and
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THE NORTH STAR HORIZON
COMPUTER
HORIZON—a complete high performance
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HORIZON is attractive, professionally engineered
and ideal for business, educational and personal
applications.
To begin programming in Extended BASIC, merely
add a CRT, Teletype or other hardcopy terminal.
HORIZON-I includes a Z80A processor, 250ns 16K
RAM; minifloppy disk and !2-slot $-100
motherboard with serial interface, all standard.
HORIZON includes the North Star DOS,
Monitor and Extended BASIC from diskette ready
at power on. Optional software includes utilities,
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COBOL, Fortran and more.
Quality at the right price:
* Horizon-1! (single drive): £1,275
* Horizon-2 (dual drives): £1,550
All prices are for assembled and tested units,
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Full details:
INTERAM Computer Systems Ltd.,
59 Moreton Street, London SWIV 2NY.
Telephone: 01-834 0261/2733
@ Circle No. 134
60
(continued from previous page)
can be handled, nor can a negative—
credit note on a sale—value of less then
£999-99 be handled. This is due primarily
to the line width of the TTY 33. Invoices
with more than one rate of VAT are
required to be entered as separate trans-
actions for each different rate. A look at
the program listings will reveal that
changing the value field sizes is straight-
forward, although one wants to be careful
about the ‘print using’ statements.
Four programs
The system consists of four programs
in the old-fashioned classic system archi-
tecture—a data entry and format validate
program, a sort, an update master file
program and finally the report program.
The data entry program collects data
entered by the user from invoices, per-
forms validation on fields, outputs to
both the list device and to a disc file.
Under CP/M many transaction files can
be created and concatenated into one
prior to the sort using PIP— Peripheral
Interchange Program, a CP/M_ utility.
Thus as long as you keep a record, data
entry can be performed as often as re-
quired. The sort uses the file created by
the data entry program as input, reads
all the records into memory, and sorts
them into ascending order based on the
13-byte key (more of which later).
Once the sort is completed, the records
are output to a file with the same name
as the input, but with an extension of
‘new’. A previously-created master file is
input to the update program, along with
the sorted transaction file. Records are
added, deleted or replaced as appropriate.
As this is being done, a listing is produced
of the actions being taken and this pro-
vides the audit trail so necessary in
accounting. As in all the programs, con-
trol totals are produced for clerical re-
conciliation.
Cassette changes
The listing of the update should be
perused by the user to spot if any errors
have occurrred and, if so, they should be
corrected by creating the appropriate
transactions using the data entry program
and performing the sort, update cycle
again. Once satisfied that all data which
should be on the master file is present—
i.e. all that period’s invoices—and it is
all correct, the report program may be
run.
The report program asks for the file
name, as do the other programs, and
then asks for the dates in which the
period falls. The dates must be correct
for the Vatman to be happy. The master
file is read and the data accumulated to
produce a report in VAT return format.
Once again, the controls should be recon-
ciled and, once done, the report tran-
scribed on to the return, signed and
posted.
For those with only cassette drives,
programs one and four can be amended
by you to run on cassettes, and this would
give some assistance to VAT record-
keeping. You would lose the ability to
sort and update, unless you had three
cassette drives but you could ensure that
all one period’s transactions went on
the transaction file, which the report
program will work from with little amend-
ment.
TDL Basic supports print and input
statements to the console—device #0
or the default device;—a list device— &
device #2; a reader—device #3; a
punch—device +4; and disc files—de-
vice +S 5 to 255. Device #1 is reserved
for the program load/save device—nor-
mally a disc file. The disc files require
to be explicitly opened. ;
Open #<Unit>, <Mode>, <File Name>
where unit is number, mode is a
string with the value of “I” for input,
“O”’ for output, “‘R’’ for random mode
and “‘U” for update in place mode. <File
Name> is any CP/M acceptable filename
string. The file is then accessed by refer-
ence to its unit number in print or input
statements, which are ASCII mode
commands.
Ease of testing
Internal format storage is also support-
ed—via write & read statements—but I
have used ASCII for ease of testing and
cross-machine support. Once a file has
been opened, if input, an EOF statement
is required to direct action at end of file;
e.g., 1200 on EOF #5 GOTO 1340.
In this system all disc data is handled
as string variable records of 63 bytes
length (not including the CR, LF). The
record size is not required by the system
as it uses the CR, LF or the ‘quote marks’
to delimit the records. Thus to read a
record:
1210 INPUT 4£3£5, TLS
This would input the next record into:
string variable TL$, where I can then
dissect it, using the MID$ and VAL (QV)
functions.
An output file must be closed to ensure
that the end of file marker is written and
CP/M marks its own EOF on the file.
This is accomplished by
1640 CLOSE 45, #6
This would close files 5 and 6, An all-
embracing close is available, which is
close without any reference to a unit. The
clear statement has an I/O function not
normally seen. A clear statement under
TDL Disc Basic has a second argument,
e.g:
CLEAR 3000, <N>
The <N> is the total number of disc
files which will be open at any one time.
This is required to reserve space for the:
file control blocks needed under CP/M.
TDL Disc Basic has numerous other I/O.
options but as none of them is invoked
I will desist from a tedious explanation.
TDL Basic has an extensive repertoire
(continued on next page)
PRACTICAL COMPUTING October 1978
NN 0001)! a.
(continued from previous page)
of ‘print using’ features, but the only one
which must be explained is the ‘LLLLLLL
feature. Where a ‘L----- L appears, a
string variable will be left justified to the
start at the’ . If the string is too long to
fit, it will be truncated on the right; if
too short, it will be filled on the right with
spaces. The + + + + +. + + is asin
other Basics.
Within the Basic program a file can be
erased or re-named and the presence of a
file determined. The formats of these
statements are as follow:
ERASE (FILENAME)
RENAME (OLD FILENAME) <NEW FILENAME)
X=LOOKUP (<FILENAME))
X=0/F FILE PRESENT, -! IF NOT PRESENT.
PROGRAM ONE, TRANSACTION
CREATE.
fod - €60 Geena INITIALISATION AND FILE
T UP.
670 = 1120 MAIN LOOP OF PROGRAM FLOW.
670 —- 1040 DATA ENTRY AND VALIDATION, VAT
CALCULATICN.
1050 - 1090 USER CONSOLE CHECK OF DATA
ENTERED.
1095 - 1120 &
1430 - 1710 DISC RECORD CREATE, LIST TO AUDIT
TRAIL OF RECORDS, TOTALS.
1130 - 1330 CONTROL TOTAL PRINT AT END OF
JOB, END OF PROGRAM.
1340 - 1410 CONSOLE PRINT OF COMPLETED
RECORD.
1730 — 1800 LIST DEVICE HEADINGS ROUTINE.
In the two example outputs accompany-
ing the program listing, user input is
underlined. Example ! is what would be
the console print if a TTY 33 was used as
console. Example 2 is the corresponding
list device output for the same run. The
effect of using a TTY as console is to
negate the advantages of using a high-
speed VDU such as a Lear Siegler
ADM3-A.
Invoice code
The first two entries on Example 1 are
the date of the run—which appears on
the list device headings—and the entry of
the filename to be created. This must
have an extension, such as ‘UNS’, if the
file is to be used in the CP/M environ-
ment, as this is needed by program two.
The entries starting at point | consist
of the tax point date, the ‘tran code’ and
a single digit number within the ‘tran
code’. The date must be as shown, namely
‘YYMMDD’. the ‘tran code’ is the
number you must associate with every
invoice. In my system, my _ invoices
are numbered with a five-digit number,
So this is used as the ‘tran code’ for sales—
the code must be five digits long.
For purchases, normally use the pur-
chase order number, as suppliers normally
quote this on invoices, and again this is
a five-digit number. It is this number
which must be on each document you
are submitting a VAT return in respect
of, even if you have to write it on the
document yourself. The serial! number
(single digit) is to allow multiple entries
per invoice for different VAT rates. It
must be a number but the program could
be amended to allow any character.
A ‘null’ entry for the tax-point date will
initiate the end-of-job process. In most
PRACTICAL COMPUTING October 1978
Basics typing a comma followed by zero,
comma, zero and return will be sufficient.
The next set of data entered consists
of a single character to indicate if the
transaction is to add, delete or replace a
record on the master file. This is followed
by up to 23 characters of ‘comment’— |
type data—normally supplier’s name and
invoice number, or customer’s name. Not
all this data is printed, but all 23 charac-
ters are held on the record. If this system
is to be interfaced to an accounts-payable
and/or accounts-receivable system, this |
field can be used for account coding
information.
The last entry indicates whether the
transaction is a normal sale(s), a normal
purchase(p), or one of the ‘specials’. A
look at the corresponding entry for
transaction 5 will show the codes avail-
able.
If a ‘D’ was entered as the transaction | |
type, no more data will be requested from | |
the user, as the rest of the fields will be
filled-in for him, as a delete does not
require values. Transaction 4 is an ex-
ample of such a transaction.
Calculates values
The third set of data requested is the
VAT rate—S for standard, A for higher
rate, and Z for zero rate. These rates are
held in the program against the code
indicated. A change in VAT rates will
require a simple amendment at statements
970-990. Secondly, the user must indicate |
if the gross value or the nett value is
about to be input. This is done by enter-
ing ‘G’ or ‘N’, The appropriate value is
then entered. The program then calcu-
lates the VAT and the value not entered.
The complete transaction is then dis-
played on the console device for the user |
to check and, if necessary, re-input to | |
correct. A carriage return entered in
reply to the ‘Return if OK? will complete
all action on the transaction by printing
it on the list device and outputting it to |
disc. If not OK, enter anything else and
you will be led through the data entry
sequence again from the beginning.
Example 2 is the corresponding list |
device output for the same run. Note the |
control totals printed at the end of the
job. Both the transaction listing and the
controls should be kept in a secure place
for use at the next stage, the sort.
For those unfamiliar with VAT terms, |
be very careful with transactions which
attract no tax. They may be zero-rated or |
they may be exempt—there is a difference. |
Refer to the appropriate VAT Guide |
(HM Customs & Excise Notice No 700).
PROGRAM TWO, THE SORT.
10 — 380 PROGRAM INITIALISATION AND FILE
SET UP
390 - 490 INPUT RECORDS AND STORE IN
STRING ARRAY.
500 ~ 580 END OF!NPUT FILE.
590 - 870 SORT LOGIC
880 ~ 1000
1010 - 1100
OUTPUT RECORDS FROM SORTED |
RRAY |
A . |
CLOSE OUTPUT FILE AND END OF |
JOB CONTROLS.
(continued on next page)
VAT TRANSACTION & MASTER FILE LAYOUT
START NO.
BYTES
6
5
I
1
23
i
1
4
7
7
6
UES FOR ST$ ARE AS FOLLOWS:-
EXPORT SALE CLASS
DEFERRED ACCOUNTING VAT IMPORT
NORMAL TAXABLE SUPPLY (SAL
ree edeenneen
MUMONBRAWNOS #&
EXEMPT TRANSACTION (SALE)
(continued from previous page)
1130 - 1240 INPUT FILE CONTROL TOTALS ROU-
1260 - 1380 OUTPUT FILE CONTROL TOTALS
1400 - 1480 PRINT ROUTINE FORINPUT FILE CON-
1500 - 1580 PRINT ROUTINE FOR OUTPUT FILE
CONTROLS.
This program is relatively straight-
forward and inspection of the program
listing will show the logic flow. Only two
| things need be noted, the use of ‘INSTR’
and the re-naming of the input file.
‘INSTR’ is a TDL Basic feature which
is an instring function. The first string
argument is searched for the occurrence
of the second string argument and its
character position, if found, is returned.
If the second string is not located a
zero is returned. Therefore, as used in
this program, the filename is searched
| for A ‘.’ (line 270). This is expected as the
program is being run under CP/M and a
file extension is expected. If not found,
the program cannot be run.
This is being used in conjuncation with
| the ‘re-name’ feature—see explantion in
| program one. To change the name of the
input file in
LINE 890, THE NAME CHANGE LOGIC IS AT LINES
290-310.
The logic for the sort was copied from
The Best of Creative Computing, Vol. 1.
Next month’s article will provide the
listings of programs three and four, the
update and report programs, as well as
the flowcharts and running instructions.
EXAMPLE I, SIMULATED CONSOLE
OUTPUT FROM VAT TRANSACTION
CREATE
RUN
VAT TRANSACTION CREATE PROGRAM
PLEASE ENTER TODAYS DATE YY/MM/DD? 78/07/10
ENTER FILENAME OF FILE TO BE CREATED?
YATTESOLUNS
TRANS oe MDD), TRAN CODE, SERIAL #?
780510, 780:
A,D, OR R; USER INFO, S POR X? A,CUST 1243, $
VAT RATE(S A BOR Z), G OR N, VALUE? SN, 195
TRANSACT TRANS Sani USER
DATE CODE #C COMMENTS
78/05/10 78021 1A CUST 1243
[te VAT GROSS) NETT VAT
oc RATE VALUE VALUE
(eres 8-00 210-60 195-00 15-60
‘RETURN’ IF OK?_,
TRANS DATE(YYMMDD), TRAN CODE, SERIAL + ?
| 780512, 78034, |
DESCRIPTION
TRANSACTION TAX DATE (YYMMDD)
DOCUMENT AUDIT CODE NUMBER
SERIAL DIGIT WITHIN DOCUMENT
TRANSACTION TYPE (A=ADD, D=DELETE, R=REPL)
COMMENT FIELD, USER DEFINED
INDICATOR AS TO INPUT OR OUTPUT VAT
INDICATOR AS TO VAT RETURN CLASS, SEE * |
VAT RATE, 2 IMPLIED DEC PL (NNVNN)
GROSS TRANS VALUE, 2 IMPLIED DEC PL
N NET TRANS VALUE, 2 IMPLIED DEC PL
v2 VAT TAX VALUE, 2 IMPLIED DEC PL
VAT DUE ON UNDERDECLARATIONS, NOTIFIED BY CUSTOMS
VAT DUE ON OTHER UNDERDECLARATIONS
VAT REFUNDABLE DUE TO ASSET PURCHASE
VAT DEDUCTIBLE ON OVERDECLARATIONS, NOTIFIED BY CUSTOMS
VAT DEDUCTIBLE ON OTHER OVERDECLARATIONS
E)
NORMAL TAXABLE PURCHASE (BOTH THESE MAY BE ZERO RATED)
A, D, OB R; USER INFO, oe P OR X?
VAT at E(S AB OR Z), G N, VALUE?
3, G, 34
TRANSACT TRANS ‘Soa USER
DATE CODE ahiG COMMENTS
78/05/12 78034 1A PAY WILLIS
1X VAT GROSS NETT VAT
(oie: RATE VALUE VALUE
Lak 8-CO 34-00 31-48 a 52
‘RETURN’ IF OK?___
TRANS DATE(YYMMDD), TRAN COCE, SERIAL + 2?
a aoeo2 O000L,
,D, ORR; US RINFO, SPOR X? D, DEL ORIG, $
TRANSACT TRANS Sal USER
DATE CODE oe] COMMENTS
78/06;02 0000 f 6 DEL ORIG
| X VAT GROSS) = NETT VAT
ONG RATE VALUE VALUE
xX X 0:00 0-00 0:00 0-00
‘RETURN’ IF OK?__
TRANS DATE(Y YMMDD), TRAN CODE, SERIAL + ?
a neg. 808. |
A,D, OR R; U oe SPOR X?
RAMEND ORIG, S
VATE het AB OR Z), G OR N, VALUE?
Z,G, 10
TRANSACT TRANS Sill USER
DATE CODE + C COMMENTS
78/06/03 78045 Lili AMEND
ORIG
[| X VAT GROSS = NETT VAT
oc RATE VALUE VALUE
OoS , 0:00 100-55 100-15 0-00
Me Ta
TRANS DATE(Y HADD), TRAN CODE, SERIAL + ?
12, 00 |
A,D, OR R; USER INFO, S P OR X? A, IMPORT, X
ENTER 2 FOR IMPORT, 6 FOR ASSET PURCHASE
3/4 FOR UNDER DECLARATIONS,
7/8 FOR OVER a
QO FOR EXPORT SALE
E FOR EXEMPT SALE
tee
VAT RATE(S A B OR Z), G OR N, VALUE?
$,.1245-68-U S$, G, 1245-65
TRANSACT TRANS $ T USER
DATE CODE aC COMMENTS
78/06/12 00120 A IMPORT
|X VAT GROSS NETT VAT
oc RATE VALUE VALUE
2 8-00 124565 1153-37 92-28
oO
‘RETURN’ IF OK?___
TRANS DATE(Y YMMDD), TRAN CODE, SERIAL a?
20,0
END OF INPUT (Y/N)
dee
END OF JOB
TOTAL RECS CREATED = 5
TOTAL GROSS VALUE = 1590-40
TOTAL NETT VALUE = 1480-00
HASH TOTAL OF VAT = 110-40
EXAMPLE 2, LIST DEVICE OUTPUT
FROM VAT TRANSACTION CREATE
78/07/10 VAT TRANSACTION CREATE PROGRAM
PAGE |
78/05/10 78021 | A CUST 1234
8/05)12 78034 1 A PAY WILLIS-INV [5
78/06/02 00001 | D DELORIG
78)06/03 78045 | R AMEND ORIG
78/06/12 00120 | A IMPORT
O S 800 210-60 195-00 15-60
1 P 800 3400 31-48 2:52
(continued on next page)
PRACTICAL COMPUTING October 1978
es Computabits
(continued from previous page)
Xx X 0-00 0-00 0-00 0-00
©O $ 0-00 100-15 100-15 0-00
O 2 8-00 1245-65 1153-37 92:28
END OF JOB
FILE CREATED NAMED baer UNS
TOTAL RECS CREATED 5
ADDITIONS = 3 (DELETIONS = |
REPLACEMENTS =
TOTAL GROSS VALUE = 1590-40
TOTAL NETT VALUE == 1480-00
HASH TOTAL OF VAT =~ 110-40
LISTING OF PROGRAM ONE, VAT
SUITE VAT DATA ENTRY & TRANS-
ACTION CREATE
REM VAT TRANSACTION CREATE PROGRAM
REM COPYRIGHT 1978 (C) XITAN SYSTEMS
120 REM WRITTEN BY G. C. LYNCH MARCH 1978
130 CLEAR 1000, |
140 $=0: TN=0
1SQ REM F$= FILENAME USED BY USER FOR
OUTPUT FILE
160 REM D$= DATE FOR HEADINGS ETC
170 REMLC= LINE COUNT
180 REM PC= PAGE COUNT
190 REM Meee TRANS DATEIN YYMMDD
FO
200 = TRANS CODE IN YYNNN
R
210 REM S$= SERIAL NO WITHIN TRANS CODE
(1 NUMERIC DIGIT)
220 REM TT$= TRANS TYPE (A ADD, D DELETE,
R REPLACE)
230 REM CM$= COMMENT OR ANY OTHER
STRING (23 DIGITS MAX)
240 REM ST$= SALE, PURCHASE OR X FOR
SPECIAL (SEE VAT RETURN)
250 REM R$ VATE RATEINDICATOR (S,A,B,
OR Z FOR EXEMPT)
260 REM G$= GROSS OR NETTINDICATOR
(G OR N)
270 REM G= GROSS VALUE
280 REM N= NETT VALUE
290 REM V= VAT VALUE
300 REMS= STANDARD VAT RATE (8-00 %)
310 REM A= HIGHER VAT RATE (12-50%)
320 REM B=RATE NOT USED
330 REM Z= EXEMPT RATE OF VAT (0-00%)
340 REM TL$= STRING PORTION OF RECORD
350 sal } FOR INPUT VAT, 0 FOR OUTPUT
360 REM
370 REM
380 SO$="""+STRINGS$("'L", 37)
390 ae Fee HEHEHE HES HE EH
400 spt heen CEG * HUTT UNIL LE 3
ata ti SESRSESE ESE HEHE HE
410 gtr *CCCC *? *LLLLLELLLLLLLLLL
*? dee ett tet se EAE. #H
420 S4$=" TOTAL GROSS VALUE
HHHHH. HH
430 $5$=:"" TOTAL NETT VALUE =
HHHHH. HH"
440 S6$="' HASH TOTAL OF VAT =
HHEHHH HH”
450 S7$=S0$+SI$
460 PRINT: PRINT” VAT TRANSACTION CREATE
PROGRAM "
470 PRINT: INPUT” fee ENTER TODAYS
DATE YY/MM/DD";
480 PRINT: INPUT HENTER | FILENAME OF FILE
TO BE CREATED”; F$
490 REM
SOO REM
510 REM NOW OPEN FILE
520 OPEN +5, “O"” F$
530 REM
540 REM
SSO REM
S60 REM INIT eis VALUES HERE
570 LC=80 : PC=
$80 TL$= SPACESS(3 8)
585 REM TOTAL ACCUMSINIT TO ZERO
S90 TG=0: TN= =0: TR=0 : TV=0
600 TA=0:TD=0:TC=0
610 REM
620 REM
630 REM
640 REM PRINT HEADINGS
6S0 GOSUB 1730
660 REM
670 REM MAIN LOOP
680 REM
683 REM DELETE NEXT STATEMENT IF YOU
DON’T HAVE CURSOR CONTROL
(ADM3A)
68S PRINT CHR$(30); CHR$(26):
690 PRINT: INPUT “TRANS DATE (Y YMMDD).
TRAN CODE, SERIAL +’; TO$, TCE, S$
700 REMIF NULL STRING INPUT AS TD$ THEN
CHECK FOR END OF JOB
710 4F LEN(TD$)=—0 THEN PRINT “END O
INPUT (Y/N)? : INPUT Z$ : IF LEFTS (Z$, 1)
="Y" THEN 1140 ELSE 685
720 T= YALGDS) : X=VAL(S$)
730 IF S$ (0" THEN PRINT “ERROR IN SERIAL
NO” : GOTO 690
740 IF S$ >"‘9" THEN PRINT “ERROR IN SERIAL
NO” : GOTO 690
750 M=VAL(MID$(TD$, 3, 2))
760 D=VAL(MIDS$(TDS, S, 2))
770 IF M <1 OR MY 12 THEN PRINT “ERROR IN
MONTH" : GOTO 690
PRACTICAL COMPUTING October 1978
910
IFO a D> Aas THEN PRINT "ERRORIN
IF TeN(rés < >5 THEN PRINT “ERROR IN
eer S$ CODE” : GOTO 690
vie
REM
REM
PRINT: INPUT ‘A, D, OR R; USER INFO,
SP OR X"; TTS, CMS, STS
CM$=LEFTS$(CMS, 23)
IF TTS (> “A” THEN IF TTS ( )"'D”
THEN 1F TTS <> ‘*R" THEN PRINT
“ERROR IN TRAN TYPE” : GOTO 830
REM IF DELETE (TT$=0) THEN FILL FIELDS
AND DON'T BOTHER WITH REST OF
INPUT
IF TT$ < )"D" THEN 890
lt on Ig="X": RG=""Z": . = 0.0:
:N=0.0:G=00 : GOTO 1040
IF Sts vr >S" THEN IF ST$ <> 'P”
THEN IF ST$ ¢)'*X" THEN PRINT
“ERROR IN VAT TYPE” : GOTO 830
IF ST$="'X"”
THEN PRINT: PRINT “ENTER 2 FOR
IMPORT, 6 FOR ASSET PURCHASE”:
PRINT” 3/4 FOR UNDER
DECLARATIONS,”: |
PRINT” /8 FOR OVER
DECLARATIONS":
PRINT’ 0 FOR EXPORT
SALE":
PRINT” E FOR EXEMPT
SALE": INPUT
ST$
“S' OR ST$="'2" OR ST$="'3"" OR
IF ST$=
Ald ‘4 OR ST$=""E" OR ST$="'0" THEN
$="0”
IF ST$="'P"" OR ST$="6" OR ST$="7" OR
ST$="'8" THEN I$ =""1""
PRINT : INPUT" VAT RATE(S A BOR 2),
G OR N, VALUE"; R$, GS, X
IFRS < sy THEN TERS (> "A" THEN IF
nae >"Z" THEN PRINT “ERROR IN VAT
RATE” : GOTO 930
IF G$ ¢ > "G" THEN IF G$ ¢ > ‘*N’ THEN
PRINT ‘.ERROR IN GROSS/NETT IND” :
GOTO 930
iF ST$="0"" ae ST$="'E" THEN R=0.00 :
GOTO 100
IF X<O THEN, PRINT “VALUE NEGATIVE,
1S IT CREDIT NOTE”; : INPUT Z$:1F
LEFT$ ZS, 1)="Y" THEN 970 ELSE 930
1F X=0 THEN PRINT "'VALUE ZERO -
ERROR": GOTO 930
IF R$="S” THEN R=8.00
A" THEN R=12.S0
Z" THEN R=0.00
IF G$=""G" THEN
Nac rv cpanl an aR N=(INT(N*100))/
IF G oe G=X:
NEN
N=X: V=(INT(R®N))/100:G =N-+V
REM
REM
REM ALL THE DATA IS COLLECTED NOW
REM GET THE USER TO CHECK IT
PRINT
REM PRINT RECORD ON CONSOLE FOR
CHECKING
GOSUB 1340
INFUT ‘RETURN’ IF OK" ;A$
REM 18 U USER SATISFIED ?1F NOT DO IT ALL
IF A$ ¢ >" THEN 680
REM CREATE RECORD, OUTPUT IT, &
PRINT IT ON LIST DEVICE
GOSUB 1430
REM si NOW DEALT WITH, START
RE
as EO) AND CLOSE FILE ROUTINES
M
PRINT 40 ; PRINT 4#0,"' END OF JOB”
PRINT 40," TOTAL RECS CREATED =°'; TR
PRINT 4¢0, USING S4$; TG
PRINT 3£0, USING S5$; TN
PRINT 40, USING S6$; TV
PRINT 40 : PRINT 40
PRINT #2 : PRINT #2,” END OF JOB”
PRINT 42, ‘FILE CREATED NAMED"; F$
PRINT 42, ‘TOTAL RECS eee ";TR
PRINT #2, “ADDITIONS = “’; TA;°
nce a ae REPLACEMENTS
PRINT 42, USING S4$; TG
PRINT 4:2, USING S5$; TN
PRINT +2, USING S6$; TV
PRINT +:2': PRINT 42
REM NOW CLOSE FILE
CLOSE #5
REM
END
Be CONSOLE RECORD PRINT ROUTINE
PRINT: PRINT
PRINT” TRANSACT TRANS ST USER
1 X VAT GROSS NETT VAT"
PRINT” DATE CODE # C COMMENTS
© CRATE VALUE VALUE’
PRINT USING $2$; LEFTS(TDS, 2), MID$
(TDS, 3, 2), RIGHTS(TD$, 2), TCS, S$, TTS,
MIDSICMS, I, 10), I$, STS, R, G, N,V
aati
M
REM CREATE RECORD, TOTAL IF UP,
(continued on next page)
(continued from previous page)
aa IT OUT, LIST IT
Ire 9 >66 THEN GOSUB 1730
Lc+l
PRINT wD, USING $3$; LEFT$(TD$, 2),
MID$(TCS, 3, 2), RIGHTS es 2), TCs,
S$, TTS, MIDS(CMS, 1 , 17), 1$, ST$, R, G, N, V
REM NOW CREATE TL$ PORTION’ OF
RECORD
MIDS(TLS, 1, 6)=TD$
MIDS(TL$, 7, 5)=TC$
MID$(TLS, 12,1)=S$
MIDS(TL$, 13, 1) =TT$
MIDS$(TL$, 14, 23)=CM$
MIDS(TLS, 37, I)=I$
MIDS(TLS, 38, 1)=ST
REM NOW TOTAL UP HASH TOTALS FOR
CONTROLS
TG=TG+G : TN=TN+N : TV=TV+V
I
TR=TR+
IF TT$=""A" THEN TA=TA+1
IF TT$-="'D"' THEN TD=TD+ |
IF TTS="R" THEN TC=TC+I
M
REM NOW GET RID OF DECIMAL POINTS
IN VALUES
REM
R—RPICO :G=G"100 : N=N*100 : V=V*100
M
REM NOW WE'RE READY TO OUTPUT
RECORD
REM
PRINT 45, USING S7$; TLS, R, G, N, V
REM FINISHED
RETURN
REM
REM LINE PRINTER HEADINGS ROUTINE
M
PC=PC+I
PRINT 42 : PRINT 42
PRINT 42," *:D$;"" VAT TRANSACTION
CREATE PROGRAM”; TAB(60);* PAGE
PRINT #2 : Le=4
RETUR
REM
LISTING OF PROGRAM TWO, VAT
SUITE TRANSACTION FILE MEMORY
SORT
REM VAT TRANSACTION SORT PROGRAM
REM COPYRIGHT (1978) XITAN SYSTEMS
REM WRITTEN BY G. C. LYNCH
REM
REM
At USES SHELL-METZNER METHOD
R
REM READS VAT TRANSACTIONS INTO
STRING ARRAY | $
REM SORTS THEM INTERNALLY
CHANGES NAME OF INPUT FILE TO
EXTENSION OF OLD
2 OUTPUTS TO FILE WITH EXT OF NEW
REM
REM
REM INITIALISATION
REM THE NEXT TWO STATEMENTS MUST BE
AMENDED FOR YOUR MEMORY SIZE
CLEAR 20000, 2
DIM | $(300)
acl
REM
EE EELLELLL
Re ide FE FEAR”
PRINT! "V VAT TRANSACTION SORT PROGRAM’
INPUT “ENTER DATE OF RUN (DD/MM/YY)
:D$
we, 42,"" VAT TRANSACTION SORT RUN
{e)
; DS
INPUT “ENTER FULL NAME OF FILE TO BE
SORTED”;
X =INSTR(FS, . ")
\F X=0 THEN 260
FI$=LEFTS(F$,X-1)
FS$=FI$: FS§¢=FS$+"'’. OLD'':FO$=FS$
FS$ =FI$: FS$=FS$+"'. NEW" :FQ$=FS$
REM
REM
REM OPEN INPUT FILE AS UNIT 5
OPEN 35, ""I', FS
Reo 4£5 GOTO 520
REM
REM READ eeeore FROM INPUT FILE
INPUT 45, TLS
REM INCREMENT RECORD COUNT
J=J+1
REM INPUT FILE CONTROL TOTALS
ROUTINE
GOSUB 1130
REM MOVE RECORD INTO INTERNAL ARRAY
1$(J)=TLS
REM NOW GET NEXT RECORD
GOTO 400
REM END OF FILE REACHED
REM Ai CONTROL TOTALS FOR INPUT
FIL
GOSUB 1400
REM CLOSE FILE
CLOSE +55
REM
REM
REM SORT ROUTINE
REM
Y=)
M6=Y
M6=INT(M6/2)
REM IF Mé6=0 THEN ITS END OF SORT
IF M6=0 THEN 870
K6=Y-M6
c7=C7+1
IF MID$(I$(16), |, 13) <=MIDS(I$(L6), I, 13)
THEN 820
N7=N7+1
REM PRINT ON CONSOLE TO SHOW SORT
STILL WORKING
PRINT"’S”;
EXCHANGE 1$(16), 1$(L6)
REM EXCHANGE |S SPECIAL FEATURE IN
TDL BASIC
REM USE FOLLOWING REM GODE IF YOU
HAVEN'T GOT EQUIVALE
REM VV$ =I$(L6) : ISL8) 1818) : 7 1$(16)=VV$
M
16=16-M6
IF I6>= THEN 690
Jo=J6+
IF 56 dé THEN 630
GOTO 680
REM END OF SORT CODE
REM
REM SORT ROUTINE COMPLETED
REM RENAME INEUT FILE PRIOR TO OUTPUT
RENAME F$,FO$
REM
REM OPEN OUTPUT FILE
i 46, 0" FO$
M
REM NOW OUTPUT RECORDS HELD IN
PRINT 4£6, I$(K)
REM OUTPUT FILE CONTROL TOTALS
ROUTINE
GOSUB 1260
NEXT K
REM
REM FINISHED WITH OUTPUT FILE
CLOSE +6
REM
REM PRINT OUTPUT FILE CONTROLS
GOSUB [500
REM
PRINT" END OF JOB"’
PRINT 4£2"’ END OF JOB”
END
REM END OF PROGRAM FLOW
a
REM
REM I/P CONTROL TOTALS ROUTINE
REM USES TL$ TO DERIVE DATA
REMIR
REMIG == GROSS VALUE (PENCE)
REMIN = NETT VALUE (PENCE)
REMIV = VAT VALUE (RENCE)
IR=IR+1
IG=IG+ VAL(MIDS$(TLS, 44, 7))
INSIN+ VAL(MIDS(TLS, 51, 7))
IV=IV+ VAL(MICS(TLS, 58, 6))
REM HASH TOTALS FINISHED
RETURN
REM
REM OUTPUT CONTROL TOTALS ROUTINE
REM USES 1$(K) TO DERIVE DATA
RE
= TOTAL RECS
REM QG = GROSS VALUE (PENCE)
REM QN = NETT VALUE (PENCE)
REM QV = VAT VALUE (PENCE)
QR=QR+1
QG=QG+ VAL(MIDS(I$(K), 44, 7))
QN=QN+4+ VAL(MID$(I€(K), 51, 7))
V=QV VAL(MIDS(1$(K), 58, 6))
Q
REM HASH TOTALS FINISHED
RETURN
REM
REM PRINT INPUT CONTROL TOTALS AT
F
EO
PRINT ce co" S$0$; "TOTAL RECORDS
INPU
PRINT 2, USING $0$; "HASH TOTALI NP
GROSS"; 1G 100
PRINT 42, ne $0$; HASH TOTAL INP
NET"; ce
SING SO$; ‘*HASH TOTAL INP
V/100
PRINT 4¢2: PRINT 4£2, “FILE INPUT AS”;
FS ‘NOW RENAMED TO"; FO$
PRINT 42
REM TOTALS NOW OUTPUT
RETURN
REM
REM ee OUTPUT CONTROL TOTALS
oh, aad S0$; "TOTAL RECORDS
pe
PRINT 4¢2, USING S0$; “HASH TOTAL OUT
GROSS"; QG 100
PRINT #2. USING SO$; “HASH TOTAL OUT
NET"; QN/100
PRINT 42, USING S0$; “HASH TOTAL OUT
VAT"; QV/100
PRINT 4¢2: PRINT #2, “FILE NOW SORTED
OUTPUT AS"; FQS$
PRINT #2
RETURN i”
PRACTICAL COMPUTING October 1978
peer | 3()/) 7) 10a vis
WIRING FOR
A SIMPLE and amusing application for
single board computers like the KIM
is to use it as a mini electronic organ.
Each key of its integral keyboard can be
used to produce a different note.
In this version we use 21 of the keys
(0 to F, AD,DA, + , GO, PC) to give
notes in ascending order from the G
below Middle C (196 Hz) to the C sharp
in the octave above Middle C (555Hz).
The waveform is not the ideal qutput of
a music generator, since it is an asymetric
square wave; the result, however, is
acceptable. The waveform is generated by
the software and is output on any of
the PIA,PAO-7 pins; the output from any
one of the pins can then be fed with suit-
able attenuation into an audio amplifier.
The program starts at Hex 200 with an
initialisation routine and carries on to a
loop at Hex 210 which looks for key
depressions.
The GETKEY subroutine of the KIM
monitor places a number, between 0 and
21, depending on which key is being
pressed, in the accumulator. That number
is placed in the index register from which it
can beused asa pointer by theinterruptrou-
tines to the correct value in the data tables.
This data value is loaded into the
counter/timer of the 6530, which generates
an interrupt to the processor after a
period determined by the data value.
Eachalternateinterrupt givesrisetoan out-
put from the PIA of either 00 or FF Hex.
; PROGRAM STARTS AT
$200
GETKEY =$IF6A
INT VEC =$17FE
PIA =$1700
PIADD =$!701
0000 XSTORE x=%+t+!
000) FF TEST .BYTESFF
0002 42
; THE INTERRUPT
HANDLER
0002 48 INTI PHA
0003 8A TXA
0004 48 PHA
0005 Aé 00 LDX XSTORE
0007 BD 32 02 LDA TABLEI,X
000A $D OF 17 STA CT1024
000D A9 00 LDA 4 $00
OOOF @D 00 17 STA PIA
0012 AI 1B LDA 4INT2
0014 8D FE 17 STA INTVEC
0017 68 PLA
0018 TAX
0019 68 PLA
OO1A 40 RTI
OOlB 48 INT2 PHA
PRACTICAL COMPUTING October 1978
TXA
PHA
LDX XSTORE
LDA TABLE2,X
LDA +tINTI
STA INTVEC
PLA
TAX
PLA
RTI
; THE MAIN PROGRAM,
START AT $0200
BACK
ELSE
TABLE |
TABLE 2
3 3#$0200
SEI
LDA +INTI
STA INT VEC
LDA +0
STA INTVEC+ 1
STA PIADD
JSR GETKEY
CMP 4$15
BCS ELSE
TAX
STX XSTORE
LDA TEST
CMP 440
BEQ BACK
LDA 40
STA TEST
CLI
BRK
Nop
JMP BACK
SEI
LDA +$FF
STA TEST
IMP BACK
“BYTE 4,4,3,3,3
(BYTE 3,2,2;2,2
aBYTE 2,2, 1,01
«BYTE I,1,1,0,1,1,1
«BYTE 126,90,184,
152,122
.BYTE 94,195,170,
146,123
-BYTE 102,82,191,
173,156
-BYTE oe tl,
80
EARPHONE
|
.
CONTROLLING
AC POWER
THE ABILITY to use a low-cost computer
like the Pet to control external AC power
devices such as electric lamps and motors
| opens a wide range of applications in a
great many fields.
The problem may appear simple; there
| | is an output port from the processor and
} one connects one of these lines to a
TRIAC or SCR and connects the load
across it. But this solution will almost cer-
| tainly prove to be dangerous and because
of noise problems make your processor
unreliable. To overcome these problems
we must separate the AC power device
ground from the computer ground and
electrically isolate the outputs of our pro-
cessor from the control circuitry.
The circuit which I shall outline is that
| required for one single control output. If
| you wish to utilise all eight outputs of a
PIA you repeat the circuit eight times.
The output from a PIA, like the 6820 or
| 6520, is a latched TTL level output, each
plied by the control circuit’s own +12v
power supply, the control circuit is shown
in fig 1. The output of the circuit A comes
from the transistor via a 680 ohm resistor,
whose function is to limit the current in
case of a short circuit; the output is about
5v at 10ma. For low power DC applica-
tions, this output could be fed into a reed
relay, which would allow control of DC
devices drawing up to -5 amps at up to
50 volts.
We want to be able to control high
power AC devices and the ideal device for
doing this is the solid state relay. The
SSR is similar in construction to an opto-
isolator, in that its input portion is an
LED. Instead of a phototransistor, how-
ever, a photosensitive resistor is used; it
provides the turn-on current of the
TRIAC portion of the SSR.
Thus we are able to control AC mains
power at currents of up to 25 amps with
I50.n.
COMPUTER
PA7
FIGI
+12V
j
of the eight lines being under independent
programme control. The first stage in the
control circuit is to feed this output into
an opto-isolator via a current limiting
resistor. This, as its name suggests, iso-
lates the rest of the control circuitry from
| the processor, thus preventing noise and
damaging voltages from reaching your
computer.
| To boost the power output from the
opto-isolator, we use an emitter follower
| NPN transistor. This transistor is sup-
a 5v 10ma input.
Fig 2 shows an SSR-based power con-
trol circuit. The resistor capacitor filter
is to suppress transients produced by
inductive loads which might cause erratic
operation of the SSR. The LED provides
an indication of the ON/OFF status and
the fuse provides overload protection.
These two simple circuits should give
some idea of how to construct sys-
tems requiring the control by computer
of large AC and DC electrical devices. Jj
—7
ia SSR
FUSE
O5pF 500V
AC POWER
PRACTICAL COMPUTING October 1978
Es 0)
Too little effort
put into
software choice
ONE of the best and most sophisticated
operating systems available for micro-
computers is known as CP/M.
It is surprising how many people tend
to give a great deal of time and thought to
choosing hardware but put very little
effort into the selection of software. Often
it is the quality of the software rather than
the hardware which makes a system per-
form well.
A very important part of the software,
especially on disc-based computers, is the
operating system software, which usually
goes under names like DOS, MINIDOS,
RDOS, CDOS or CP/M.
The operating system is the software
which integrates and controls all the
individual components of a computer
system. It can be regarded as a software
interface between the machine code en-
vironment and the high-level language
environment.
Widespread use
It is the operating system which con-
trols the speed and efficiency of disc
access by the high-level language. Some
operating systems also provide user func-
tions like disc copying and initialisation,
as well as offering the user the ability to
look at and change sections of RAM in
disc.
The choice of operating system also
determines the range of software you can
run on your system. Thus, some operating
systems will allow you only to run soft-
ware from one manufacturer, while others
will allow you to use a wide range.
In its various forms CP/M has been in
widespread use for more than three years
and with a price tag of around £50 re-
presents amazing value in a software
package.
Easy to alter
CP/M is marketed by an American
company, Digital Research. The package
is defined as a control program/monitor
for a microcomputer system employing
Intel 8080 or Zilog Z80 CPU and IBM-
compatible flexible disc for back-up
storage.
Its importance lies not only in the
success and universal use of the 8080 and
its extended family of chips, but also in the
ease with which CP/M can be altered to
work in different configurations.
The secret of its easy re-configuration
is its highly-structured and modular
design. Although it was developed origi-
PRACTICAL COMPUTING October 1978
nally for the Intel MDS 800, its structure
and excellent documentation has attract-
ed the attention of other manufacturers.
Consequently, CP/M can be obtained for
a variety of 8080 micro systems employing
hard- or soft-sectored, single- or dual-
density, mini- or full- size floppy discs.
Sophisticated
CP/M is essentially a monitor system.
The term ‘monitor’ may not be obvious to
those who have not developed programs
in interactive environments but, as it
suggests, it simply monitors, in particular,
the operator’s keyboard. A monitor pro-
gram would, for example, reflect, in a
duplex system, the keyboard input to a
video monitor or terminal printer and at
the same time respond to a set of com-
mands which execute programsor routines.
This is what CP/M is about. Time-
sharing users and computer operators will
be very familiar with the advantages of an
interactive monitor and those with such
experience will appreciate the sophistica-
tion of commands available under CP/M.
Starting-up CP/M is much like any
other disc operating system with a two-
stage cold and warm ‘boot’. As the sys-
tem springs to life, it outputs a sign-on
message to the console, followed by a
prompt to indicate the monitor is ready
for acommand.
Similarity
Those used to developing programs on
sharing systems could probably guess
what to do next. Type in DIRECTORY,
perhaps? Right. In fact, the command is
abbreviated to DIR and, as you would
expect, a list of the files on the directory—
in this case a floppy disc—is produced at
the console device.
The size of files or directories can be
determined by the statistics or STAT com-
mand. Another command, TYPE, follow-
ed by a filename, will list ASCII files at
the terminal. Other simple commands
also exist for re-naming files (REN), eras-
ing files (ERA) and copying files (PIP).
Digital users may feel that some of this
looks familiar and the similarity of CP/M
to Digital systems continues. For example,
where have you seen the file name exten-
sion BAS before? This extension and
others allow the user and system to identi-
fy file types.
One file extension, COM, is particularly
important. If you fee! you would like an
(continued on next page)
HB COMPUTERS
East Midlands Area
Distributor for
PET 2001
Visit our showrooms at:
22 NEWLAND STREET,
KETTERING
for personal service with technical
and programming back-up.
Machines normally available for
hands-on experience. Many other
systems stocked, including
indivdualcomponents, MUPs,
memories, etc.
Call or write for details.
KETTERING 83922
“SS Circle No. 15!
SIRTON PRODUCTS (se)
ASCII Keyboard kit with case
VDU board with case + reverse
£38-50
video + character flash £88-50
Used 9” Video Monitors, cased £38-50
13 Warwick Road, Coulsdon, Surrey
CR3 2EF. Tel: 01-660 5617
@ Circle No. 152
the MODULAR 25
expandable snap keyboard
* gold plated p.c.b.
* 290 legend sheet
* slim line
* only £8-50
* legend sheet £1-00
HAYWOOD ELECTRONIC
ASSOCIATES LTD.
11 Station Approach.
Northwood .
Middlesex U.K. .
Tel: Northwood 28301
@ Circle No. 153
TOPMARK
Computers
dedicated to
APPLE Il
Simply the best!
Full details from Tom Piercy on
Huntingdon (0480) 212563 or circle
enquiry card.
@ Circle No. [54
67
J&A COMPUTERS
MERLIN video boards best $100 graphics from
£275.
EQUINOX & EQUIBOX 8080 or 780 systems
from £445.
SHARP & ASSOCIATES the famous IBM
selectric TM can be interfaced with these kits
from £170,
SD COMPUTER PRODUCTS 8K memories
(STATIC) £120. Versafloppy Controller £149 ete.
NEW PRODUCTS—SEND FOR LISTS
15 Fleetwood Gardens,
MARKET HARBOROUGH,
Leicestershire LEI6 9LX.
Tel: 0858 7620
@ Circle No. 155
Pet Programs
—all on cassette and ready to run.
Othello £8-00; Pontoon £6:00; Wraptrap £8-00;
Noughts and Crosses £3-00; Lunar Lander £8-00;
Rotate £5-00; Biorhythms £8-00; Mastermind
£500; Weekly Payroll £25:00 giving weekly-
monthly and year end summaries, visual display or
printed wage slip; Disassembler £15-00; Machine
Code Handler £3:00; PET Handbook £5-00; PET
Introductory Booklet £1:00; 6500 Programming
Manual £5-00; Please add 0:50p for post and
packing.
Intex Datalog Limited,
Eaglescliffe Industrial Estate,
Eaglescliffe,
Stockton on Tees,
Cleveland TS16 OPN
Telephone (0642) 7881193
@ Circle No. [56
Visit our
CALCULATOR & COMPUTER
SHOPS
FOR
HEWLETT PACKARD. TEXAS INSTRUMENTS.
CANON. CASIO,
COMMODORE P.E.T.
Software & Accessories stocked.
at: LEEDS WILMSLOW
10 Blenheim Terr. 82a Water Lane
Woodhouse Lane Tel: 29486
Tel: 459459
HOLDENE LTD.
@ Circle No. 157
THIS SPACE COULD BE WORKING
FOR YOU
You can advertise your shops, products
and services in our Shop Window columns
for only £6 per single column centimetre
(minimum 5cm). For details, contact:
Wim Hoeksma, Practical Computing,
2, Duncan Terrace, London N.I.
Tel: 01-278 9517
68
(continued from previous page)
additional command in your monitor set,
program and test it, call it whatever COM
and you have a new command.
Another close similarity to Digital soft-
ware is the CP/M text editor. ED filename
initiates a very powerful character and
line-editing system which compares fa-
vourably to the best editors available on
large time-sharing systems.
It’s a delight
The editor allows paging in chunks of a
file, string searching, string substitutions,
moving a character pointer and inserting
or deleting characters or lines. A casual
user might find it a little difficult to cope
with but those who are modifying code
frequently will delight in using this super
program development aid.
Along with CP/M is a standard Intel
8080 assembler. In general, one assembler
looks much like another and the only
features of the CP/M assembler worth
mentioning are directives such as ORG,
EQU, SET, IF and ENDIF—the last
three provide good facilities for condi-
tional assemblies. Diagnostics are as help-
ful as most assemblers and the product
of the assembly is a print and a hex file
written to disc.
With bonus
LOAD, predictably, loads the HEX
files into memory. More exicting are the
debugging aids in the program DDT.
Facilities are fairly extensive and allow
direct input of code, display of code in
HEX,ASCII or mnemonics, movement of
segments of memory and substitution of
memory valves or CPU register content or
state. Finally, debugged programs can
be saved back on disc by the SAVE
command.
CP/M is flexible to different hardware
configurations and to this end the input/
output drivers are available as source files.
The size of the CP/M system can be modi-
fied from 16K upwards and after the
BIOS (Basic input output system), which
contains the drivers, has been ‘patched in’
using the aids mentioned, the new system
can be saved back on disc with SYSGEN.
Finally, CP/M _ usually has _ one
bonus piece of software free—a BASIC-E
compiler, Although BASIC-E would be
considered by most a fairly indifferent
BASIC, it has an extended Dartmouth
BASIC set and at the price must be con-
sidered excellent value.
The documentation to CP/M is excel-
lent. The five manuals are available for
around £15. Compared to most system
manuals, they are extremely well-written
and, even more surprisingly, accurate.
Outside CP/M are several other fea-
tures which indirectly make the product
look more interesting. For example, there
is an extensive CP/M users’ library. It
embodies 20 full diskette volumes of
‘public domain’ software, and, at about
£10 per volume, they represent exceptional
value.
Free entry
The content varies from esoteric
utilities to general business packages and
games. The CP/M Users’ Club costs noth-
ing to join and details are available from
The Editor, Practical Computing, 2 Dun-
can Terrace, London, NI. (Please send a
stamped-addressed envelope).
Yet one other exciting aspect of CP/M
has to be mentioned—Microsoft products
for CP/M. Microsoft, an American
organisation, has developed undoubtably
the best set of micro software which runs
under CP/M. It includes the Microsoft
BASIC interpreter—this is very similar
to Altair BASIC—-an ANSI FORTRAN
compiler, an ANSI Cobol compiler and
most recently, APL and PASCAL. The
price range of these interpreters/compilers
is as low as £150-£400.
Even the pundits who criticise the 8080
series hardware for particular applications
have to admit that software systems such
as CP/M and an 8080 disc system out-
perform in facilities, though not necessar-
ily in speed, many of the minis on the
market. |_|
Library club for
CP/M users
A users’ club library for CP/M has been
established. We have received a listing of
the first 14 volumes of discs in the library
and look forward to seeing and using some
of the programs when our copies of the
discs arrive.
All the programs are free of copyright,
so anyone is free to use them or modify
them, we are told. The following is a brief
list of extracts from the contents:
Vol 1: 34 various CP/M utility pro-
grams; driver routines for both Diablo
and Qume printers; diskette-to-cassette
and cassette-to-disc transfer; disassem-
blers; CP/M 1/0 subroutines.
Vol 3: a collection of 39 games pro-
grams written in BASIC-E, including old
favourites like Amaze, Black Friday,
Lunar Lander, Wumpus and for those
with enough memory, a 27K Startrek.
Vol 4: contains some interesting-looking
programs, including ML80, which is
described as a Macroprocessor; and
(continued on next page)
PRACTICAL COMPUTING October 1978
eres Tpit 2 its
(continued from previous page)
Actor, which is described as an inter-
preter.
Vol 5: contains both a compiler and an
interpreter version of BASIC-E and a
small list of programs written in Micro-
soft BASIC, like Othello and Startrek.
Vol 6: programmes from the Chicago
area Computer Hobbyist Software Ex-
change, the most interesting of which is
probably the cache mail list programes.
Vol 7: another disc for people interested
in unusaul Janguages, this is Pilot, an
educational language with a linguistic
rather than a numeric base. An improved
version of Pilot for the Z-80 is on Vol 12.
Disc formatter
Vol 8: a further set of 28 CP/M utility
programmes including a disc formatter
for systems using the Tarbell controller or
any other controller using the WD1771
chip. Those with a Bytesaver should find
the PROM blowing programme useful.
Vol 9: the complete set of 12 pro-
grames in the General Ledger Package,
by Bud Shamburger, first published in
Interface Age, September, 1977.
Vol 10: the replacement for Vol. 2 and
contains the Lawrence Livermoor version
of Tiny BASIC.
Vol 11: A Tiny Basic with disc handling
which runs in 5K, written by Processor
Technology.
Vol 13: a mixed collection of 21 pro-
grams written in Microsoft Basic and | |
Basic-E; mostly games.
Vol 14: another set of CP/M utilities,
including a disc viewer program which
will dump on to a standard console file,
CP/M groups, or sectors in ASC11 or
Hex format simultaneously.
Expansion hope
As a result of a meeting at the DIY
Computer Show in June, a Cromemco and
North Star Users’ Group has been set up
in the U.K. It has only 15 members but
since it is known that there are more than
200 machines by the two manufacturers
in the U.K., there are great hopes it will
expand.
The aims of the group are to promote
the free interchange of information and |
experience in both hardware and software |
between users and anyone else who is
interested. Computabits is prepared to
provide space in each issue for members ||
to publicise their activities.
The next meeting of the group will be in
September. If you are interested in joining
please contact the editor of Computabits.
Pilot new language
for micros
A NEW language for micros called Pilot is
available from Computer Workshop.
Pilot (Program Inquiry Learning or
Teaching) can be used for controlling
interactive conversation with a computer.
It is capable of being used successfully by
very inexpert programmers, but is also
attractive to the expert.
It is built around four instructions—
Type, Accept Input, Match Input, Con-
ditional Jump. ‘Accept input’ will literally
take anything.
Match input will search the input
for a variety of things such as an em-
bedded numerical answer, an embedded
keyword, a choice or combination of key-
words, or gross mis-spelling of keywords.
The Jump may be made dependent on
the previous Match or use a condition, as
in Basic.
All-round aid
The importance of such a language
must not be under-estimated. It is useful
for an accountant to be able to type
“print-out time sheet for Jones Ltd” and
then the computer sorts out each file as
required and takes appropriate action.
It is useful for a teacher to have a pro-
gram which accepts a French phrase,
‘points out spelling mistakes, wrong
PRACTICAL COMPUTING October 1978
tense, and the like. In the past this has
not been possible, except on large systems
in complicated languages. It
mal programming skills.
Passing it on
4
To help get things going, a Pilot Users’ |
Group has been set up. ‘‘We hope to hear |
from people who have produced some-
thing useful and we shall organise dis- |
tribution of the information,’ says
Charles Sweeten, director of computing
at Oundle School, who is also Secretary of
MUSE (Minicomputer Users in Secon- |
dary Education).
If you are interested in the user group
contact Philip Couzens, Oundle School, |
Oundle, Peterborough.
NOTE: Certain programs reproduced in |
Practical Computing remain the copyright
of the contributor. Readers wishing to use
such programs should first obtain the |
permission of the copyright holder. Every |
attempt has been made to ensure accuracy |
but |
Practical Computing cannot be held res- |
ponsible for any errors or the effect of |
of the programs and listings
errors contained therein.
is now |
possible on a cheap micro and with mini- |
a arene (56)
Buzzwords
The term buzzword is a piece of
jargon used to describe the jargon
the computer industry generates
with such whole-hearted enthusi-
asm, and which this glossary is
hopefully an aid to penetrating.
Byte
If abit is the smallest unitofinform-
ation stored in a computer, thena
byte is the smallest unit with any
real meaning. It is a collection,
normally, eight bits, which to-
gether represent a number or a
character. Sharp-eyed readers will
note that ASCII is eight-bit code;
so one byte usually corresponds to
one character, and the terms char-
acter and byte are frequently used
interchangeably. For example, a
floppy disc holding 71KB( =7/,000
bytes) wiil store 71,000 characters.
Well, it will not quite do that,
since the usable capacity is always
less than the manufacturer
says it is because of internal for-
matting considerations.
Cards
One of the oldest forms of input
medium and now somewhat-out-
moded. They may be long and
slim and capable of holding rep-
resentations of 80 characters, or
short and fat and capable of
holding up to 96 characters. IBM,
and not many other companies,
uses the 96-character card.)
Those characters are rep-
resented by combinations of holes
punched in the cards. If your
computer uses an_ eight-level
character code, and if you have an
80-column card, the card will be
organised as an 80 x 8 matrix—
80 columns vertically, eight rows
horizontally. The character code
determines which of the eight
possible punch positions denotes
which particular character. Unlike
most other input media, you can
rest coffee cups on cards, write
addresses on them, and lose or
damage single records easily.
Incidentally, 80-column cards
were so widespread in the early
1960s that this became a de facto
standard for record lengths, which
is why so many terminals and
other things assume you require
lines 80 characters long. The
irritating point about cards is that
a record is always at least one card
long—even if you want only one
or two characters on it, you still
have to use a whole card. You can
forget about cards, anyway.
CCD
Charge coupled device is a new
memory technology of bubble
memory. Expensive and not yet
readily available.
Cartridge
There are two kinds of cartridge.
Tape cartridges are almost in-
70
A PRACTICAL
GLOSSARY
Running the terminological gamut from B to C
variably made by 3M; they are
like a cassette but they hold more,
are more expensive, and more
robust.
Disc cartridges hold from 2:5
to 10 Megabytes. They are the
next stage from floppy discs and
cost more.
Cassette
Philips has set the standard for
both audio and data cassettes.
Micros will work happily on audio
cassettes, although if you need to
keep data very clean and tidy, you
will probably have to pay more
and buy a data cassette
Character
A letter or numeric digit. Included
here for completeness, although
you know exactly what it is any-
way.
Chassis
The computer chassis is the box
which contains the processor and
main memory. It incorporates
various elements, like the back-
plane, so It is an integral part of
the computer system rather than
a receptacle.
Checkpoint
See breakpoint.
Chip
A chip is a piece of silicon, nor-
mally about a quarter of an inch
square and thick, holding the
components which make up all or
part of a microcomputer—one
micro may be split across several
chips. It is effectively the medium
which holds the message. Anyone
who uses the phrases “chips with
everything” or “when the chips
are down” automatically gets the
Practical Computing Dumb Award,
which consists of an on-line boxing
glove loaded with a horseshoe for
ritual self-effacement.
Clock
The rate at which a computer per-
forms operations is controlled
internally by a clock. That is an
electronic circuit or group of elec-
tronic components which generate
a set of control signals. Each set of
control signals will initiate an
action on the part of the central
processing unit (CPU).
COBOL
The Common Business Orientated
Language is one of the best-known
high-level programming languages.
It was designed for commercial
applications, so its mathematical
abilities are limited—some of us
can sympathise with this. Because
it has been designed to make
program-writing easy in a com-
mercial context, it can take up a
good deal of room in the com-
puter; this makes it more popular
on farger systems rather than
micros. Having said that, there
are at least two Cobols for micros
and they are British.
CODASYL
The organisation responsible for
the design of Cobol and an at-
tempt to produce a database
manager which is universally
accepted. It lives in the United
States, consists of representatives
from government bodies and
suppliers of computer systems and
services, and promotes standard-
isation. Its outpourings are de-
tailed and esoteric, which means
that Cobol- and Codasyl-compat-
ible database systems are complex
and verbose.
Ic stands for Committee on
Data Systems Languages.
Code
A code in computer terms means
the same as in other contexts; it
is a means of representing one
thing by something else, James
White, in Your Home Computer
(recommended) says. Sometimes
a code is used for secrecy: in a
computer a code is used for ef-
ficiency. Some programmers are
confused by this.
The most common codes in
computing, used to represent
numbers and letters, are ASCII
and EBCDIC. qv. (Which Is code
for ‘which see’).
Communications
This one is a real jungle of tech-
niques and terminology. As a
blanket term, it can refer to com-
puter systems where one part is
linked to another to allow trans-
mission of information over a
communications line which is
normally an ordinary telephone
line. Things become very compli-
cated when there are numbers of
system components sending data
to each other, and a whole sub-
culture has developed in the com-
puter industry which concerns
itself with exactly how you
organise those components and
the information flowing between
them.
So let us remain with the simple
end; communications are what
happens when two system com-
ponents communicate, and they
communicate by sending data to
each other.
Compiler
The language in which instructions
for the computer are written—
in theform ofa program, normally
—is not one which the computer
can use directly. It needs to be
changed into a form which the
computer can recognise. One
way of doing this is to use a
compilér.
A compiler is a specialised pro-
gram which translates the source
program into code the computer
can execute. It does so much
faster than the other method of
translating the instructions, which
involves using an interpreter. The
interpreter has the great virtue,
however, of enabling the user to
change bits of a program and test
the change immediately, which
makes it very useful for program
development.
You can also interrupt an inter-
preter in full spate to get some
intermediate results, say, and then
let it carry on. A compiler would
not like you to do that.
What goes into a compiler is
source code; what comes out is
object code.
Computer
A computer is a clever collection
of components which enables you
to put information in, store it,
modify it, and get it out again.
That is a very arbitrary definition
and one which would fit a program-
mable calculator, too. A program-
mable calculator can be distin-
guished from a computer by its
name—the distinction is a market-
ing one.
Console
What you do to mournful micros.
Also the control point of a com-
puter system from the human op-
erator's point of view. It is prob-
ably a keyboard and printer or
VDU, for inputting messages to
the system and getting back a re-
sponse.
Sometimes the term is used for
the front panel of a mini or a
micro, the switches and/or push-
buttons which initiate system
operations. Some minis have a
programmer’s panel or program-
mer’s console. which include
switches to set the contents of
particular memory locations.
Content Addressing
A method of obtaining infor-
mation in the main computer
memory by scanning it to find that |
information specifically. Conven-
tionally, you have to ask the com-
puter to tell you what is in a
particular address.
You need the very special, very
expensive, and very unproven
content, addressable memories,
to do it. The idea sounds great in
principle.
CORAL
CORAL, usually CORAL 66, is a
language developed for real-time
applications by the Royal Radar
Establishment at Malvern. It is a
trifle esoteric for the micro user.
Still, the hills there are pleasant.
PRACTICAL COMPUTING October 1978
The new Texas Instruments
Programmable TI-58 and TI-59 make your
problem solving simpler and easier by
making the electronics do more work.
Now, commonly encountered programmes
in maths, science, finance and statistics
are set up and accessible at the touch of
‘a key. You need add only the variables.
Solid State Softwaret is the name of
this technological achievement from
Texas Instruments. Even the
programming is now included in the
solid-state electronics. You get complete,
pre-written problem solving libraries in
convenient plug-in modules. Yet, no prior
programming knowledge is necessary.
The programmable TI-58 at £99.95*
Includes a Master Library Solid
State Software module packed with 25
useful programmes, all at your command.
Or you can key-in your own programmes
and store the data — using up to 480
programme steps or up to 60 memories —
and employ the Master Library
programmes as subroutines.
Optional plug-in library modules are
available to convert your calculator into a
specialised problem solver in the fields
of applied statistics, surveying, aviation,
navigation — with many more 5,000-step
libraries to come.
The programmable TI-59 at £249.95*
Includes all the features of
the TI-58 — plus more programme steps,
more memories, and a magnetic-card
capability. Record your own programmes
on convenient magnetic cards and store
them permanently in your personal
problem-solving library.
The Texas Instruments
Programmable TI-58 and TI-59 and the
compatible PC-100A alphanumeric
printer/plotter include a 1-year
warranty. See the world’s most powerful
pocket calculators now.
Or use the coupon to obtain full product
information,
| Please send me full details on the TI-58, TI-59 and
PC-100A.
| Name r - = |
| Address = |
Simulated Calculator Display.
Giant technology. From the people who made micro-electronic calculators and watches possible.
+Trademark of Texas Instruments
“Suggested retail price, including VAT.
Texas Instruments Ltd, Supply Division, Manton Lane, Bedford. Tel: Bedford (0234) 67466.
Branch offices at: Slough - 0753 33411, Edinburgh - 031 2295573, Stockport - 061 442 7000, Southampton - 0703 27267
@ Circle No. 309
a
MUPLTER scomerescavcere
LLORAS THE MICRO-COMPUTER BUYER
Courses
You don't need to.know a CPU from a VQU to benefit from our Courses.
PEOPLE PRICES SUBJECTS
Courses for Businessmen 3-day Courses £100 BASIC
Courses for Teachers 1-day Courses £ 40 Word Processing
Courses for Engineers 5-evening Courses £ 25 ASSEMBLER
Courses for Hobbyists Applications
Courses for Doctors Med. Interviewing
Courses arranged for Groups on request.
All Courses guaranteed to be in ENGLISH. Do NOT bring your dictionary of Computer
Jargon. Courses held at our Training School conveniently situated in the West End.
Application Packages
Text Editing and Word Processing £50.
Allows you to create and edit text files on disk or tape. Then with sophisticated control
of spacing, margins, justification, and many other features, a perfectly formatted manual,
letter, book, or whatever can be produced on the printer. Users of this type of program on
large mainframe Computers find themselves immediately ‘‘at-home’’ with this package.
Information Retrieval/Selective Mailing/Subscription Accounting £25.
This very versatile package allows you to create and maintain files of information
(Databases to some) with as complicated (or simple) a structure of analysis codes as you
need. Allows for entry of Cash Received and automatic generation of Subscriptions Due if
required. The power of the selection routines allows you to enter as many parameters as you
want for comparison with the records on file. For instance an Estate Agent could select all
the houses with more than 2 bedrooms and a garage less than 5 miles from a station in the
20 to 25 thousand pound price bracket.
Watch This Space For More Applications Descriptions In Following Months _ Issues.
Equipment. SWTPC, Centronics & Ricoh
Computers £275 - £975 (256-40K Memory). Twin Minifloppy £860.
1.2 megabyte Twin Floppy £1,525. VDU £455. Printers £250 - £1,800.
Printers from 40-col. dot matrix to double daisy wheel typewriters.
Maintenance, Leasing & Software Development
Arranged through specialist companies.
User Group Meetings
Held on the last Monday of every month at Dover Street.
COMPUTER WORKSHOP. 38, DOVER STREET, LONDON. W1X 3RB. 01-491 7507
COMPUTER WORKSHOP. 29, HANGING DITCH, MANCHESTER M4 3ES 061-832 2269
@ Circle No 310
Open Library