JPH05233400A - Disk controller with cache - Google Patents

Abstract

PURPOSE:To efficiently use a cache memory at the time of registering a high- speed file to be stored in only the cache memory. CONSTITUTION:When a data area on a disk device 7 is registered as a high- speed file on a cache memory 6, a set is allocated to a block including the data area by a set allocating part 8 in a directory memory 5, and it is registered as a high-speed file block in the block of the pertinent set on a cache memory 5 which is preliminarily allocated to plural sets; and even when no registerable block is present thereon since all of blocks in the pertinent set are used as high-speed file blocks, the set having the largest number of idle blocks among the other sets is judged by an idle block management part 11 in the directory memory 5 to tentatively use the idle blocks of the set, thereby registering blocks including the requested data area as the high-speed file blocks.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cached disk control device, and more particularly to a cached disk control device for controlling a high speed file in which files are stored only in a cache memory.

[0002]

2. Description of the Related Art Conventionally, a disk control device with a cache of this type has a much smaller cache memory capacity than a disk device, and therefore data on the disk device must be efficiently allocated to the cache memory. When each of the above data areas and cache memory are allocated to multiple sets respectively and the data area is registered as a high speed file on the cache memory, only the set on the cache memory corresponding to the set allocated to that data area is registered. It was possible to register.

The set on the disk device is further divided into entries, and the set on the cache memory is divided into levels, which are divided into blocks.

Next, in the conventional disk controller with cache, a process for registering a data area on the disk device within one block which is actually allocated to the set n in the cache memory as a high speed file will be described. In this case, the cache memory set n
Can only be registered for.

The high speed file registration data is received, the non-high speed file block belonging to the set n on the cache memory is searched, and if the requested block is already registered, this block is deleted from the registration of the non high speed file block. Register as a high speed file block.

If not registered in the non-high speed file block, it is confirmed whether or not there is a free block belonging to the set n, and if it exists, the high speed file is registered in the free block.

If there is no free block, it is confirmed whether or not there is a non-high speed file block, and if there is, the oldest accessed block in the non-high speed file block is deleted from the non-high speed file block registration,
Register the requested block as a high-speed file block in the block that became an empty block. If it does not exist,
All blocks in the set are used as high-speed file blocks, and new high-speed files cannot be registered. Therefore, this was considered an error and abnormal termination was performed.

[0008]

The above-mentioned conventional disk control device with a cache divides each data area on the disk device in block units by sets and entries, and divides the data area in the block assigned to the set number n. When registering as a high-speed file in the cache memory, it is possible to register only in one of the blocks belonging to the set number n of the cache memory that is similarly divided into blocks according to the set and level. When blocks belonging to n are registered as high-speed file blocks and are all used, there is a problem that the data area assigned to the set number n on the disk device cannot be newly registered in the cache memory as a high-speed file. ..

Further, when only a part of the blocks belonging to a specific set of the cache memory is registered and used as a high speed file or non-high speed file block, many blocks remain unused in the set. Therefore, the number of blocks used for each set of the cache memory varies, which causes a problem that the cache memory is not used efficiently.

An object of the present invention is to eliminate the above-mentioned drawbacks and to register a data area on a disk device allocated to a plurality of sets as a high speed file in a cache memory similarly allocated to a plurality of sets. An object of the present invention is to provide a cached disk control device capable of registering a high-speed file even when there is no registerable block in the set.

[0011]

An apparatus of the present invention manages a host processor, a cache memory connected to a disk device for recording a plurality of files to store a plurality of files, and the cache memory by a set associative method. In a disk control device having a directory memory, set allocation means for dividing the data on the disk device into a plurality of sets in the directory memory and efficiently allocating the data to a cache memory, and registration of a high-speed file for storing files only in the cache memory And high-speed file management means for performing management, non-high-speed file management means for registering and managing files other than high-speed files in cache memory, and free block information for each set in cache memory required for high-speed file registration Have Even if a high-speed file registration command is issued from the host processor to the director for a data area on the disk device allocated to a set with no free blocks, high-speed file registration is possible by temporarily using the free blocks of another set. And block management means.

[0012]

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

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. The disk controller 2 of the embodiment shown in FIG. 1 includes a director 3 and a director 4 which are connected to share a host processor 1 and a disk device 7, a cache memory 6 for storing a plurality of files, and a plurality of cache memories 6 in the cache memory 6. Directory memory 5 for managing files of
A set allocator 8 in the directory memory 5, a high-speed file 12 in the cache memory 6, which is built in the directory memory 5, divides the data on the disk device 7 into a plurality of sets, and allocates the data to the disk cache efficiently.
A non-high-speed file 13 and a free block 14, a high-speed file management unit 9 that is built in the directory memory 5 and manages the high-speed file 12 in the cache memory 6, and a non-high-speed file that manages the non-high-speed file 13 in the cache memory 6. The management unit 10 and the empty block management unit 11 in the directory memory 5 that manages the empty blocks 14 in the cache memory 6 are provided.

FIG. 2 is a diagram showing the contents of the data area in the disk device 7 of FIG. 1 divided into blocks by sets and entries. For example, the block 50 is a block represented by the set number 2 and the entry number 1.
The number of sets and the block size representing the number of logical sectors per block are preset, and the number of entries is determined by these.

FIG. 3 is a diagram showing the contents of the cache memory 6 of FIG. 1 divided into blocks according to sets and levels. For example, the set 51 is a set represented by the set number 2. The number of sets and the block size are preset, and the number of levels is determined by these. The number of levels depends on the capacity of the cache memory 6, but since the capacity of the cache memory 6 is much smaller than that of the disk device 7, it is much smaller than the number of entries.

FIG. 4 shows a free block number management table of the free block management unit 10 of FIG. 1, and from the first free block number 200 indicating the free block number in the set number 0,
It is composed of the n-th free block number 20n indicating the number of free blocks in the set number n.

FIGS. 5 and 6 are first and second half flowcharts showing the processing contents when the director 3 or the director 4 of FIG. 1 receives a high speed file registration command from the host processor 1, respectively.

Next, the operation of this embodiment will be described with reference to FIGS.

From the host processor 1 to the director 3,
For example, a case where a command for registering the data area in the block 50 designated by the set number 2 and the entry number 1 in the disk device 7 in the high speed file 12 in the cache memory 6 is issued will be described as an example.

In this case, high-speed file registration in the cache memory 6 is possible only for blocks of each level belonging to the set 51 of set number 2.

The director 3 receives the data area in the disk device 7 from the host processor 1 as high speed file registration data (step 20), and the set allocation unit 8 corresponds to the requested data area, which is a block 5 shown in FIG.
The set number and entry number of 0 are determined, and at the same time, the number of blocks is determined (step 21).

Since there may be a plurality of request blocks, an initial value for processing the first block is set next (step 22), the non-high speed file management unit 10 is searched, and the request block 50 is set. Check if there is a block that matches number 2 and entry number 1 (step 2
3).

If there is a matching block (step 2)
4) Since the requested block 50 has already been used as a non-high speed file block, the registration of the non-high speed file block is canceled and registered as a high speed file block (step 35), and when there is no matching block (step 24) Next, the corresponding set 5 in the empty block number management table shown in FIG.
1 (step 25), if there is a free block (step 26), it is registered as a high speed file block (step 34), and if there is no free block (step 26), the non-high speed file management unit 10 is searched again (step 26). Step 27).

If there is a non-high speed file block (step 28), the oldest accessed block (LRU) in the non-high speed file block is deleted from the non-high speed file block registration (step 32), and the block becomes an empty block. The requested block 50 is registered as a high speed file block (step 33).

When there is no non-high speed file block (step 28), the free block number management table is searched again (step 29), and the set having the maximum number of free blocks, that is, the cache memory is not effectively used. The set number of the set to be set (step 3
0), the requested block 50 is registered as a high speed file block in the free block of the set having the maximum free block number (step 31).

Next, the number of blocks is incremented (step 36) and the process for the next block is started. If the number of requested blocks is exceeded (step 37), the process is terminated.

[0027]

As described above, according to the present invention, the data area on the disk device allocated to a plurality of sets is
Similarly, when registering as a high-speed file in the cache memory allocated to a plurality of sets, even if a block that belongs to the set is registered and there is no registerable block in the set, an empty block in the empty block management unit is registered. The number management table is searched to determine the set with the maximum number of free blocks of other sets, and the free blocks are temporarily used to register the high-speed file, thereby depending on the variation in the number of blocks used for each set. There is an effect that the cache memory can be used remarkably effectively without any need.

[Brief description of drawings]

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

2 is a diagram showing the contents of the data area of the disk device 7 of FIG. 1 divided into blocks by set number and entry number. FIG.

FIG. 3 is a diagram showing the contents of the cache memory 6 of FIG. 1 divided into blocks according to set numbers and levels.

FIG. 4 is a diagram showing the contents of a free block number management table of a free block management unit 11 of FIG.

5 is a first half flow chart when the director 3 or 4 of FIG. 1 receives a high speed file registration command from the host processor 1. FIG.

6 is a second half flowchart when the director 3 or 4 of FIG. 1 receives a high speed file registration command from the host processor 1. FIG. [Explanation of Codes] 1 host processor 2 disk controller 3, 4 director 5 directory memory 6 cache memory 7 disk device 8 set allocation unit 9 high-speed file management unit 10 non-high-speed file management unit 11 empty block management unit 12 high-speed file 13 non High speed file 14 Free block

Claims (1)

[Claims] 1. A disk controller comprising a host processor, a cache memory connected to a disk device for recording a plurality of files and storing a plurality of files, and a directory memory for managing the cache memory by a set associative method, A set allocating means for dividing the data on the disk device into a plurality of sets in the directory memory and efficiently allocating the set to the cache memory; a high speed file managing means for registering and managing a high speed file which stores the file only in the cache memory; A non-high speed file management means for registering and managing files other than high speed files in the cache memory, and free block information for each set in the cache memory required for high speed file registration. Even when a high speed file registration command regarding a data area on a disk device allocated to a set having no free block is issued, a free block management means for enabling high speed file registration by temporarily using the free block of another set A disk control device with a cache having: