JPH0337748A - External storage accessing system utilizing main storage - Google Patents

Abstract

PURPOSE:To improve the processing speed of a data processing system by allocating the data into a cache memory at the time point of an input/output request is generated. CONSTITUTION:Whether data of an external storage device 5 supplied by an input 1 exists already on the present allocation area of a cache memory 3 or not is checked by using a file pointer 31 and an in-file relative record address 32 in a cache memory control block 30. As a result, in the case of the data concerned exists on the cache memory 3, the input 1 is processed by using an area of the cache memory 3, and in the case of it does not exist, a cache memory control table control means 20 decides whether a new cache memory area can be allocated or not by a use ID 33 in the management block 30. As a result, when the allocation can be executed, management information related to the area of the cache memory 3 allocated newly is generated in the area of the cache memory control block 30. In such a way, a search time of data can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a data processing system, and more particularly to a memory access method that uses a portion of a main storage device as a cache memory of an external storage device.

[Conventional technology]

Conventionally, in a data processing system having a cache memory as described above, the cache memory is always searched from the beginning of the cache memory until data is found every time data is exchanged.

[Problem to be solved by the invention]

In the data processing system described above, a search is performed from the beginning of the cache memory until the data is found, so if data that is frequently exchanged is located at the back of the cache memory, the search until the data is found is delayed. The disadvantage is that it takes time.

[Means to solve the problem]

The external storage access method using main storage according to the present invention provides a main storage space in a data processing system that includes an external storage device and a main storage device and uses a part of the main storage device as a cache memory of the external storage device. and a cache memory management block that manages the cache memory.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

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

In the figure, the external storage access method using the main memory includes a control program 10, a cache memory management table control means 20, and a cache memory management block 30.
, a main storage device 4 whose main storage space is partially used as a cache memory 3 , and an external storage device 5 .

The control program 10 gives an input 1 which is an operation instruction to the cache memory management table control means 20 in accordance with an input/output request from the user program OO, and exchanges data with the user program OO by an output 2 which is a response.

The cache memory management table control means 20 manages management information for each area of the cache memory 3 provided in the main storage device 4 in each area of the cache memory management block 30.

FIG. 2 is a flowchart showing the operation of the cache memory management table control means 20. In the figure, when input 1 regarding reading or writing is received from the control program 10, step S1 determines whether the data in the external storage device 5 given by the input 1 already exists in the currently allocated area of the cache memory 3. , using the file pointer 31 and in-file relative record address 32 in the cache memory management block 30 (see FIG. 3).

If the corresponding data exists in the cache memory 3 as a result of this existence check, input 1 is processed using the area of the cache memory 3 where the data exists, and output 2 is returned to the control program 10 ( S2).

When it is found that the corresponding data does not exist in the cache memory 3 through the above existence check, the cache memory management table control means 20 determines whether a new cache memory area can be allocated using the usage ID 3 in the cache memory management block 30. (S3).

If allocation is not possible, the control program 10 is notified of this fact, and the control program 10 abandons, for example, input/output control using the cache memory of the user program OO at that time (S4).

On the other hand, if allocation is possible, the cache memory management block 30 is updated by creating management information regarding the newly allocated cache memory area 3n in the area 30n of the cache memory management block 30 (S
5〉. If the request from the control program 10 is a read request, data is read from the external storage device 5 into the allocated cache memory area 3n and output 2 is given to the control program 10, and if the request is a write request, the data is allocated. The data is transferred to the area 3n of the cache memory, and output 2 is given to the control program 10 (S6).

As described above, the cache memory used by a certain user program is subsequently released when it becomes used. Various methods can be adopted as this release method, and for example, the following method can be used. That is, when a series of processes by a certain user program is completed and a file close command is issued to the control program 1o, the control program 10 uses cache memory management to release an area of the cache memory 3 that was used only by that user program. The table control means 2° is notified by input 1. Upon receiving this notification, the cache memory management table control means 20 updates the cache memory management block 30 and releases the cache memory by deleting the management information regarding the cache memory area used only by the user program.

The cache memory management block 30 is controlled by the cache memory management table control means 20 as follows.

When data is exchanged using the cache memory 3, the pointer of the management block in the cache memory management block 30 is changed after the data is exchanged6.For example,
In FIG. 4, if data is exchanged via the cache memory 33 managed by the management block 303, then the management block 30. The pointer n is stored in the first block pointer of the cache memory management block 30.

Further, when data is added to or deleted from the cache memory 3, the pointer of the management block is changed after registration and deletion of the management block in the cache memory management block 30. For example, in FIG.
If data is added to , a management block 304 is created in the cache memory management block 30, and the pointer of the management block 304 is stored in the first block pointer of the cache memory management block 30 (
S7).

〔Effect of the invention〕

As explained above, the present invention allocates data in the cache memory at the time an input/output request occurs, thereby reducing the time required to search for frequently exchanged data and dramatically increasing the processing speed of the data processing system. There is an effect that can improve the situation.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a flowchart showing the processing of the cache memory management table control means 20, FIG. 3 is an explanatory diagram of the cache memory management block, and FIGS. 4 and 5 is an explanatory diagram showing an example of operation. 1... Input, 2... Output, 3... Cache memory, 4... Main storage device, 5... External storage device, 10
. . . control program, 20 . . . cache memory management table control means, 30 . . . cache memory management block.

Claims (1)

[Claims] In a data processing system that includes an external storage device and a main storage device and uses a part of the main storage device as a cache memory of the external storage device, a cache memory management that controls a main storage space as a cache memory of the external storage device. An external storage access method using a main memory, characterized by comprising table control means and a cache memory management block that manages the cache memory.