JP2735400B2 - Asynchronous I/O control method - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THEINVENTION The present invention relates to an asynchronous input/output control method for an external storage device.

[0002]

2. Description of the Related Art In a conventional asynchronous I/O control system of this kind, I/O to an external storage device is executed in the order requested by a user program, and only the number of I/O operations is executed.

[0003]

In the above-mentioned asynchronous I/O control method, I/O to the external storage device is executed in the order requested by the user program (----) regardless of the frequency of access, resulting in the problem that unnecessary I/O (,) occurs and the data in the asynchronous I/O buffer is not used effectively. In other words, since I/O is performed in block units, it is sufficient to write the latest data for that block, but in the above example, the first half of the - is updated by the second half of the --.

[0004]

[Means for solving the problem] The asynchronous I/O control method of the present invention comprises an asynchronous I/O buffer management block control means for controlling main memory space as an asynchronous I/O buffer for an external storage device, and an asynchronous I/O buffer management block for managing the asynchronous I/O buffer, and is characterized in that, upon a write request from a user program, write data is copied to the asynchronous I/O buffer and a response is returned to the user program, thereby writing data in the asynchronous I/O buffer to the external storage device asynchronously with the user program.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, which comprises a control program 10, an asynchronous I/O buffer management block control means 20, an asynchronous I/O buffer management block 30, an asynchronous I/O management task 40, a main memory device 4, part of whose main memory space is used as an asynchronous I/O buffer 3, and an external memory device 5.

FIG. 2 is a flow chart of an example of processing by the asynchronous I/O buffer management block control means 20, FIG. 3 is a flow chart of an example of processing by the asynchronous I/O management task 40, FIG. 4 is an explanatory diagram of the asynchronous I/O buffer management block 30, and FIG. 5 is a detailed diagram of the management block shown in FIG. 4.

[0008] In response to an I/O request from the user program 00, the control program 10 gives an input 1 which is an operation instruction to the asynchronous I/O buffer management block control means 20, and transmits and receives data between the control program 10 and the user program 00 by using an output 2 which is a response to the input.

The asynchronous input/output buffer management block control means 20 manages the respective areas (1) to 3(n) of the asynchronous output buffer 3 currently provided in the main memory as shown in FIG.
The management information for the asynchronous I/O buffer is managed in areas 30(1) to 30(n) of the asynchronous I/O buffer management block 30. When an input 1 for writing is received from the control program 10, an area of the asynchronous I/O buffer 3 corresponding to the input 1 is secured and values are set in each of the areas 31 to 37 of the asynchronous I/O buffer management block 30 (S1), as shown in FIG. 2, for example.

If an area has already been reserved in the asynchronous I/O buffer 3, a check is made to see if the asynchronous I/O buffer 3(n) is in use based on the usage ID 35 in the asynchronous I/O buffer management block 30 (S2), and if it is in use, the asynchronous I/O buffer 3 enters a waiting state for an available space (S3).

Next, the access frequency is judged by the access ID 37 (S4). The access ID 37 indicates the access frequency and is set to ON for frequently accessed data, such as data in the key portion of an index file. If the access ID 37 is ON, the management block is searched from the head pointer of the asynchronous I/O buffer management block 30, and the last block of the management blocks with the access ID set to ON is located (S5).

If the access ID is OFF, the management block is searched for using the head pointer of the asynchronous input buffer management block 30, and the last block of the management blocks with the access ID OFF is located (S6). As a result, the more frequently accessed a block is, the slower the writing becomes, so that the occurrence of unnecessary I/O can be suppressed.

Next, the corresponding area 3 of the asynchronous input buffer 3
The data received at input 1 from control program 10 is transferred to (n) (S7), and the presence or absence of a write request is determined by write ID 36 (S8). If there is no write request, write ID 36 is turned on and a write request is issued (S9).

Next, the usage ID 35 is turned on to obtain exclusive control of the corresponding area 3(n) of the asynchronous I/O buffer 3 (S10). Then, a write command is issued to the asynchronous I/O management task 40 (S11), and output 2 indicating completion of writing is given to the control program 10 (S12). In this manner, output 2 is notified to the user program 00 before the actual writing process.

Next, the actual write process will be described. In response to a write command (S12), as shown in FIG. 3, the asynchronous I/O management task 40 acquires the block 30(n) from the head pointer of the asynchronous I/O buffer management block 30 (S13), and judges whether the block 30(n) is in use from the usage ID 35 (S14).
14).

If it is in use, the next management block is obtained from the next pointer in the asynchronous I/O buffer management block 30 and judged. If it is not in use, the write ID 36 in the asynchronous I/O buffer management block 30 is used to judge whether it is a management block to be written into (S15). If it is not a management block to be written into, the next management block is obtained,
Judge.

The management block to be written is written to the external storage device 5 based on the information of the data address 33 and data size 34 in the asynchronous I/O buffer management block 30 (S16).
is turned off (S17).

[0018]

All asynchronous input buffer control blocks 30 are checked according to the above procedure, and when there are no more control blocks to be written, the asynchronous input/output control task 40 enters a processing wait state (S20).

[0020]

As described above, the present invention stores data in an asynchronous I/O buffer when a write request occurs, and the actual writing is performed by a separate task, eliminating the write wait time for the user program.

[0021] Also, with regard to asynchronous I/O, by rearranging the I/O order according to the access frequency as shown in Figure 7, data can be used more effectively and unnecessary disk I/O can be reduced, resulting in a dramatic improvement in the processing speed of the data processing system.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a flow chart of an example of processing by the asynchronous I/O buffer management block control means 20.

FIG. 3 is a flow chart of an example of processing of an asynchronous I/O management task 40.

FIG. 4 is an explanatory diagram of the asynchronous I/O buffer management block 30.

5 is a detailed diagram of the management block shown in FIG. 4.

FIG. 6 is a diagram for explaining a problem to be solved by the present invention.

FIG. 7 is a diagram for explaining the effect of the present invention.

[Explanation of symbols]

1 Input 2 Output 3 Asynchronous I/O buffer 4 Main memory 5 External memory 00 User program 10 Control program 20 Asynchronous I/O buffer management block control means 30 Asynchronous I/O buffer management block 40 Asynchronous I/O management task

Claims (2)

(57) [Claims] Claim 1: A computer comprising a plurality of areas for storing data.
and an asynchronous I/O buffer including a plurality of areas, each of which includes a plurality of areas.
Correspondingly, the external storage area for the data written to the area is
The information on the write order to the area and the access frequency of the data
A plurality of management blocks each having an access ID indicating whether the access ID is high or low.
Asynchronous I/O buffer management block that stores locks
and for writing to the external storage device from a user program .
data and information on whether the data is accessed frequently or not
and writes the received data to the user program.
A control program means for returning a response related to the processing, and the control program means for transmitting the data and the access to the data.
and information on the access frequency, and for writing the data.
The area is allocated in the asynchronous I/O buffer.
The asynchronous I/O buffer management block corresponding to the area
The access ID of the management block in
Store frequency information and, if the data is accessed frequently,
In this case, the management block is transferred to the asynchronous input/output management block.
Access I, which indicates high access frequency in the network
Ordered after all other control blocks that contain D,
In addition, if the access frequency of the data is not high,
The control block is placed in the asynchronous I/O control block.
Including an access ID indicating that the access frequency is not high
Ordered and secured behind all other managed blocks, including
The data is written to the area where the data is written.
A response indicating that the loading has been completed is returned to the control program means.
asynchronous I/O buffer management block control means for controlling each management block in the asynchronous I/O buffer management block;
Each management block is written according to the write order information that the block has.
Write to the area of the asynchronous I/O buffer that corresponds to the
The data stored in the memory is extracted and written to the external storage device.
and an asynchronous I/O management task for writing
An asynchronous I/O control method. 2. The asynchronous I/O buffer management block.
is also the data that is first written to the external storage device.
The asynchronous I/O buffer area storing
A head pointer pointing to the management block is included, Each of the plurality of management blocks further includes
Before and after storing data written to external storage device
Other management blocks corresponding to the asynchronous I/O buffer area
It contains a previous pointer and a next pointer to the block, The asynchronous input/output buffer management block control means
The control program means provides data and access to the data.
When the frequency information is received, the data is written.
If the area has not yet been reserved in the asynchronous I/O buffer,
If the amount is not available, the amount will be newly secured. If the amount is already secured, the amount will be
allocates the area as is, and the area that corresponds to the allocated area is allocated.
A management block in the asynchronous I/O buffer management block
The access ID of the data is stored with information on the frequency of access to the data.
If the data is accessed frequently,
The previous pointer of the block and the asynchronous I/O management block
Access ID that indicates high access frequency within
The last management block of the other management blocks including
Set the next pointer to point to each other's management block.
Also, if the data is not accessed frequently,
The previous pointer of the management block and the asynchronous input/output pipe
This indicates that the access frequency is not high within the logical block.
The last entry in the other management block that contains the access ID
The next pointer of the management block and the next pointer of the management block
Set it to point to the area and write the data to the allocated area.
At the same time, a response is sent to the effect that writing of the data has been completed.
returning the control program means to said control program means; The asynchronous I/O management task
The head pointer in the data management block and each management block
By following the previous and next pointers of each
The area of the asynchronous I/O buffer corresponding to the management block
The data written in the external memory is extracted.
2. The asynchronous write operation according to claim 1,
Input/output control method.