JPH05342152A - Buffer control system - Google Patents

Abstract

PURPOSE:To provide the buffer control system capable of accessing a file at a high speed in a cache buffer controller for controlling a file transfer between a main storage device and a disk device. CONSTITUTION:The system is constituted of a cache buffer controller 1 having information for managing a block of a file, a file deciding means 2 for registering and deciding a resident file, a main storage device 3, a disk device 4 and a program 5. By allowing a buffer to be resident in the main storage device 3 by a block (data) unit of the file, an access between the main storage device 3 and the disk device 4 becomes unnecessary, and a quick access is enabled irrespective of size of a cache and the number of times of a data access. Also, a table managed by a program up to the present is managed as a file by using the buffer control system of this system, by which at the time of changing a program, etc., the changing work quantity is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a buffer control system of a cache buffer control device for controlling data transmission between a main memory device of a computer and a disk device.

[0002]

2. Description of the Related Art Conventionally, in an input / output device of a computer operation system, a main storage device (hereinafter abbreviated as memory) has been used to speed up access of a magnetic disk device (hereinafter abbreviated as a disk) having a slow access speed. The cache control used is used. The cache control is a method of improving access performance by storing data requested by a program for input / output in a memory instead of directly accessing the magnetic disk device. However, the data stored in the memory is finally recorded on the disc.

In order to store the data on the memory, it is necessary to identify a plurality of mounted disks and the storage positions on the disks. A unique device number is assigned to the device for disc identification. There are two methods for allocating the recording position on the disk: a logical block number for each file and a physical disk position (a number for each cylinder or a sector number). Only the logical allocation method to which the present invention is concerned will be described below.

In the logical allocation method, the cache is managed in units of files and a number is assigned to each file. In addition, the minimum unit for accessing the disk is a block (for example, 512 bytes), and a number is assigned from the beginning for management. Here, cache control using a logical allocation method will be described through a means for accessing a disk from a program. In order to write data to the disc from the program, the file is opened, the head is moved to the writing position, and a write request is issued. The cache control manages the information of the opened file and the block corresponding to the requested position as the device number, the file number, and the block number, and registers the writing in the block on the memory.

When the data written by the program is read, it is not necessary to access the read disk from the block on the memory. Further, although it is necessary to access when reading from the disk for the first time, access to the disk is not necessary for subsequent read requests from the program.

Since the memory used for cache control is not unlimited, in order to use it efficiently, LRU (Least
Recently Used rule) method is used. The LRU method is a method of discarding a block on the memory that is least used. In the case of cache control, the information to be managed in the order of access requests is connected to the end of the queue, and the oldest read / write request block is returned to the disk by fetching from the head of the queue. This process is called a sweep process.

[0007]

However, in the conventional cache control device, when there is data which the program does not access frequently but wants to access at high speed,
High-speed access cannot be performed because there is a possibility that the LRU method will be the sweep target. Therefore, in the conventional program, since such data is held in the memory as a fixed table in the processing of the program and managed, the program becomes complicated, and the fixed table is accessed by a plurality of programs. Therefore, there is a problem in that a discrepancy occurs due to the change.

The present invention has been made in view of the above-mentioned problems, and eliminates the above-mentioned problems and enables a high-speed access buffer in a cache buffer control device for controlling data transmission between a main storage device and a disk device. Provide a control method.

[0009]

In order to solve the above problems, the present invention comprises a main storage device 3, a disk device 4 and a cache buffer control device 1, as shown in FIG. In the buffer control method of the main storage device 3 for controlling data transmission between the main storage device 3 and the disk device 4, the file determination means 2 for registering and determining the attribute of the file is provided.
It is characterized in that the attribute of the file to be made resident in is registered in the file determination means 2, and the information processing of the file is performed only by accessing the main storage device 3 to speed up the file access.

[0010]

According to the present invention, by making the buffer resident in the main storage device 3 in units of file blocks (data) by the above means, access between the main storage device 3 and the disk device 4 becomes unnecessary, and the size of the cache is increased. It is possible to provide a file that can be accessed at high speed regardless of the number of data accesses. Further, by managing the table which has been managed by the conventional program as a file by using the buffer control method of the present method, it is possible to reduce the amount of modification work when the program is modified.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a diagram showing a processing flow of the buffer control system of the present invention, and FIG. 2 is a block diagram showing a configuration of an apparatus to which the buffer control system of the present invention is applied. As shown in FIG. 2, the present apparatus is a cache buffer control apparatus 1 having information for managing file blocks, a file determination means 2 for registering and determining a resident file, a main storage device (memory) 3, a disk device 4, and a program. It is composed of 5.

FIG. 1 is a processing flow of a buffer control system for securing a block, which is not a target of LRU, on a memory for each file. A description will be given according to the configuration diagram of FIG. 2 and the procedure of FIG. First, the device number 11 and the file number 12 are registered in the file determining means 2 in order to place the files required for high-speed access on the main storage device 3 for buffer control (step ST11). An input / output request from the program 5 is accepted (step ST12). The cache buffer control device 1 converts the input request into the block number 13, and the device number 11, the file number 12, and the block number 1
The buffer for the requested block in the main memory 3 is searched from 3 (step ST13).

Next, it is judged whether or not there is a buffer in the main storage device 3 (step ST14), and if there is a buffer, the management information is removed from the list for LRU (step ST15). It is checked whether the requested block is a file registered in the file determination means 2 (step ST1).
6). The device number 11 and the file number 12 are passed to the file determination means 2 for searching. When the file is not registered (step ST17), the management information is linked to the end of the list for LRU (step ST18).

When the file is registered in the file determining means 2 (step ST17), the management information is not subject to the sweeping process because it is not connected to the queue, and is always stored in the main storage device 3. Therefore, high speed access becomes possible. Finally, the data is copied to the predetermined position of the program 5 which is the request source by copying the buffer contents on the main storage device 3 (step ST19) and the process is repeated from step ST12.

When the buffer is not in the main storage device 3, it is necessary to store the buffer in the main storage device 3. At this time, if there is a room to secure a buffer in the main storage device 3 (step ST20), a buffer is secured (step ST23), and if necessary, the data is deleted from the disk device 4.
Data to the main storage device 3 (step ST24). Then, as in the case where the buffer exists, step ST16
Return to.

When the buffer cannot be secured in the main storage device 3 (step ST20), the management information is removed from the head of the LRU list for the buffer that is least used to secure the buffer (step ST21). Then, the contents of the buffer are written to the disk device 4 (step ST22). As a result, the contents of the buffer are discarded and the buffer is secured, and the process returns to step ST23.

The above-described buffer control system of the present invention is not frequently used, for example, when searching a postal code from an address, or conversely when searching an address from a postal code, but when it is used, it is prompt. Used when you want the result to.

[0018]

As described in detail above, according to the present invention, the following effects are expected. (1) By making a buffer resident in the main storage device in block (data) units of a file, access between the main storage device and the disk device becomes unnecessary, regardless of the size of the cache and the number of data accesses. It is possible to provide files that can be accessed at high speed. (2) Further, by managing the table which has been managed by the conventional program as a file by using the buffer control system of this system, it is possible to reduce the amount of modification work when the program is modified.

[Brief description of drawings]

FIG. 1 is a flowchart of a buffer control system of the present invention.

FIG. 2 is a block diagram showing a configuration of an apparatus to which the buffer control system of the present invention is applied.

[Explanation of symbols]

 1 cache buffer control device 2 file determination means 3 main storage device 4 disk device 5 program

Claims (1)

[Claims] 1. A buffer control system for a main storage device comprising a main storage device, a disk device and a cache buffer control device, wherein the cache buffer control device controls data transmission between the main storage device and the disk device. In, a file judgment means for registering and judging the attribute of the file is provided, the attribute of the file to be made resident in the main storage device is registered in the file judgment means, and the information processing of the file is performed only by accessing the main storage device. A buffer control method characterized in that