JPH01274257A - Disk input/output system - Google Patents

Abstract

PURPOSE:To prevent the efficiency of input/output from being lowered by increasing the existence probability of a high-order file on a cache memory by forming the cache memory in hierarchical structure, and using the cache memory fitting in the hierarchical structure of the file. CONSTITUTION:A magnetic disk device 4 is provided as the external memory device of a central processing unit 1, and hierarchically formed data is stored in the magnetic disk device 4. The magnetic disk device 4 is provided with a hierarchically formed cache memory 6 in an input/output part. Data to be inputted to and outputted from the central processing unit 1 is inputted and outputted via the hierarchically formed cache memory 6 corresponding to the hierarchy.

Description

[Detailed Description of the Invention] [Summary] Regarding the data input/output method in a magnetic disk device, by providing a cache memory with a hierarchical structure and using the cache memory in accordance with the hierarchical structure of files, it is possible to The purpose of this system is to increase the probability of the existence of files and prevent a decline in input/output efficiency.The central processing unit has a magnetic disk device as an external storage device, and stores hierarchical data on the magnetic disk device. In a computer system, a hierarchical cache memory is provided in the input/output section of a magnetic disk device, and data to be input/output to a central processing unit is input/output via the hierarchical cache memory according to the hierarchy. Configure.

[Industrial application field]

The present invention relates to a data input/output method in a magnetic disk device, and more particularly to a disk input/output method that achieves high speed input/output by using a hierarchical buffer memory.

In magnetic disk drives, a buffer memory (cache buffer memory, or cache memory) is provided to speed up input/output, which apparently shortens the input/output time.

In a buffer memory for input/output of such a magnetic disk device, it is desired to prevent a decrease in input/output efficiency for data having a hierarchical structure and to increase the speed of input/output.

[Conventional technology]

FIG. 3 shows a conventional disk input/output method. That is, when the application program 12 in the central processing unit (CPU) 11 outputs data from the magnetic disk device 13, it reads from the cache memo 1/4 and the corresponding data is stored in the cache memo 1.
When it is not on month 4, it is read from the magnetic disk 15 onto the cache memory 14 and output. Data read from the magnetic disk 15 remains on the cache memory 14 until erased.

Furthermore, when inputting data from the application program 12 in the central processing unit 11 to the magnetic disk device 13, writing is performed to the cache memory 14, and the data is stored in the cache memory 14 for inputting other data. When the data cannot continue to exist, it is written to the magnetic disk 15.

[Problem to be solved by the invention]

As shown in FIG. 3, in the conventional disk input/output method, the cache memory that mediates input/output to and from the magnetic disk device does not have a hierarchical structure, but consists of a single layer.

However, the files recorded on the disk device are
Some have a hierarchical structure.

FIG. 4 conceptually shows a file with a hierarchical structure.

In FIG. 4, File is the topmost file, and the files below it are F21. There is F22. Also file F
21. Below F22 are files F31 to F3, respectively.
n, F41 to F4n. Furthermore, files F31, F
3, F41. Below F4n are the lowest files F51 to F5n, F61 to F62. F71~F
There are 73 degrees F81 to F8n.

Files with such a hierarchical structure are accessed by sequentially following links from higher-level files and accessing lower-level files.

Therefore, in the input/output method using the cache memory, it is important to increase the probability of existence of higher-rank files on the cache memory as high as possible in order to improve overall file access efficiency.

However, in a cache memory with a single hierarchical structure, when there is no free buffer at the time of an input/output request, there is a high possibility that the buffer into which the higher-level file has been read will be used. Therefore, there is a problem in that the existence probability of upper-level files on the cache memory becomes low, and access efficiency decreases.

The present invention is an attempt to solve the problems of the prior art, and aims to provide a cache memory with a hierarchical structure,
By using the cache memory in accordance with the hierarchical structure of files, the purpose is to increase the probability that higher-rank files exist on the cache memory and prevent a decline in input/output efficiency.

[Means to solve the problem]

In the disk input/output method of the present invention, as shown in the embodiment of FIG.
In an electronic computer system that stores hierarchical data, a hierarchical cache memory 6 is provided in an input/output section of a magnetic disk device 4.

Thereby, data to be input/output to the central processing unit 1 is input/output via the hierarchical cache memory 6 according to its hierarchy.

[For production]

FIG. 2 provides a detailed explanation of the invention.

If the files on the magnetic disk 21 are layered as level 1 files, level 2 files, . . . , level II+-1 files, and level m files,
Buffer the cache memory 22 to level 1.

Level 2 buffers are hierarchized like l-1 level n buffers, and level 1 files on the magnetic disk 21 are stored in the level 1 buffer of the cache memory 22, and level 2 files and level 3 files on the magnetic disk 21 are stored in the cache memory 22. Stored in level 2 buffer, level m-1 file on magnetic disk 21, level n of all level m files in cache memory 22
Store in buffer.

Data input to the application buffer in the main memory of the central processing unit is performed for each hierarchical buffer in the cache memory 22.

As a result, it is possible to prevent a decrease in the existence probability of frequently accessed high-rank files on the buffer, and as a result, it is possible to prevent a decrease in overall file access efficiency.

Here, files at each level are read only into the buffer at the level corresponding to that level, but it is not necessary that there is a one-to-one correspondence between the two, and in general, due to cost constraints, it is common to However, even in this case, a sufficient effect can be expected by making the buffer and file hierarchies correspond l to n.

〔Example〕

FIG. 1 shows an embodiment of the present invention.

In the figure, 1 is a central processing unit, and application programs 2. It has a file management program 3. 4 is a magnetic disk device, and an input/output control program 5. It has a cache memory 6 and a magnetic disk 7. The cache memory 6 is hierarchical,
Level 1 buffer 61. Level 2 buffer 62.・
-, consists of level n buffers 6n. Here, the hierarchical levels are level 1>level 2>->level n.

The input/output control program 5 is located between the file management program 3 and the magnetic disk device 4 and controls data input/output. Further, the file management program 3 is located between the application program 2 and the magnetic disk device 4, selects files to be input/output according to the hierarchical structure of files, and provides input/output commands to the magnetic disk device 4. The operations of each component based on input/output requests from the application program 2 are performed as follows.

(2) The file management program 3 outputs input/output commands from the highest level file to the target file in order to the magnetic disk device 4 based on the file hierarchical structure in accordance with a request from the application program 2. At this time, a level code is added to the command depending on the hierarchical level of the file.

(2) In accordance with the input/output command from the file management program 3, the input/output control program 5 checks whether data of the corresponding file exists in the cache memory 6 at the corresponding level. As a result, if the relevant data exists on the buffer at the relevant level in the cache memory 6, the data is immediately transferred between the buffer and the application program 2.

If the relevant data does not exist on the buffer at the corresponding level, the input/output control program 5 reads the relevant data from the magnetic disk 7 into the corresponding buffer on the cache memory 6, and then transfers the data between the cache memory 6 and the application program 2. Transfer data between.

Note that when the corresponding data is not on the buffer, if there is space in the corresponding buffer, the data is read into that area, and if there is no space, the area where another file has already been read is written to the magnetic disk 7. Afterwards, read the target file into that area.

By doing so, it is possible to prevent a decrease in the probability of existence of a high-level file in the cache memory 6, and therefore, a decrease in file access efficiency from the perspective of the application program 2 can be prevented.

〔Effect of the invention〕

As explained above, according to the disk input/output method of the present invention, unlike the conventional input/output method using cache memory, when inputting/outputting data (files) with a hierarchical structure, several hierarchical roots are Since there is no problem that input/output efficiency decreases when input/output is repeatedly performed, and high input/output efficiency can be maintained, it is expected that the processing capacity of the computer system as a whole will be improved.

[Brief explanation of the drawing]

Figure 1 is a diagram showing an embodiment of the present invention, Figure 2 is a diagram explaining the invention in detail, Figure 3 is a diagram showing a conventional disk input/output method, and Figure 4 is a file with a hierarchical structure. FIG. 1-Central processing unit (CPU) 2-Application program 3-File management program 4--Magnetic disk device 5--=-Person output control program 6-----Cases memory 6, ~6n・-Buffer 7・-・magnetic disk

Claims (1)

[Claims] A computer system having a magnetic disk device (4) as an external storage device of a central processing unit (1), and storing hierarchical data in the magnetic disk device (4), comprising: A cache memory (6) is provided in the input/output section of the magnetic disk device (4), and data to be input/output to the central processing unit (1) is passed through the hierarchical cache memory (6) according to its hierarchy. A disk input/output method characterized by input/output.