JPH02165247A - Memory device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a storage device equipped with a disk cache memory or the like provided to speed up data reading from a disk in a data processing system or the like.

[Conventional technology]

In general, the main memory of a computer is particularly slow in access compared to the arithmetic processing unit, so a high-speed buffer memory, a so-called cache memory, is provided between the two to prevent the processing speed from decreasing due to the main memory. A similar concept is applied between a magnetic disk device (hereinafter simply referred to as a disk) and the Conbuque main unit, and there is a buffer between the two.
It has been proposed to provide a memory, a so-called disk cache memory, to effectively shorten the access time.

FIG. 3 is a block diagram showing the configuration of a conventional disk cache system disclosed in, for example, Japanese Patent Publication No. 63-31806. Give to 2. The input/output processing device 2 searches the disk cache memory 3 in response to a given data read command, and transfers the data to the main storage device 5 via the data transfer device 4. The input/output processing device 2 also activates the disk device 8 via the input/output channel 6 and the disk control device 7, reads data and writes it into the disk cache memory 3, and transfers the data to the main unit via the data transfer device 4. Transfer to storage device 5. These arithmetic processing unit 1, input/output processing unit 2, and input/output channel 6 are connected to the main processor 1 through a system interface circuit 9, respectively. a Access the device 5.

Next, the operation of the disk cache will be explained.

When the input/output processing unit 2 receives a disk data successive output instruction from the arithmetic processing unit 1, it searches whether the requested data exists in the disk cache memory 3 or not. If the requested data exists, the data is transferred via the data transfer device 4 to the specified Q position in the main storage device 5, and the series of operations is completed.

Furthermore, if the requested data does not exist in the disk cache memory 3, the input/output processing device 2 reads the data from the disk device 8 via the input/output channel 6 and the disk control device 7, and stores it in the disk cache memory. Write in 3.

At this time, if there is no free space in the disk cache memory 3, the data with the lowest priority is erased and written in blue, or it is written off. Next, the requested data is transferred from the disk cache memory 3 to the designated storage location of the main storage device 5 via the data transfer device 4, and the series of operations is completed. Thereafter, if there is a read request for this data, the access time will be shortened since the data exists in the disk cache memory 3.

[Problem to be solved by the invention]

In the conventional disk cache system configured as described above, data sequentially read from a predetermined address of the disk device is recorded in the disk cache memory, and the data is not necessarily accessed next time. There is a problem in that high data is selected and stored in the disk cache memory, and the efficiency of the disk cache is low.

The present invention has been made in order to solve such problems, and includes a device described in item 1a that increases the probability that required data exists in a memory that can be accessed quickly, such as a disk cache memory, and speeds up data access. For the purpose of providing.

[Means to solve the problem]

The storage device of the present invention includes means for reading data having a length multiple times the data length to be transferred to an external device from the first means, and means for writing the read data into the second means. It is characterized by having

[Effect]

The device a described in the present invention reads the data from the first storage means and transfers it to the outside of the device if the required data does not exist in the 0 means described in the second description as a result of searching the 9 means described in the second description ↑. . Further, data having a length multiple times the data length to be transferred to the outside of the device is read from the first storage means, and the read data is written to the second storage means.

[Actual example]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on drawings showing embodiments thereof.

FIG. 1 is a block diagram showing the configuration of a disk cache control device according to the present invention. Lo in the figure is a disk cache control device, which is connected to the host system 3o via the 5C3I hash 20. In the disk cache control device 1o, the micro combinator 101 has S
The data given from the host system 30 via the C3I bus 2o is transferred to the small capacity processor 102. control circuit 103 or disk cache memory 5, while small capacity buffer 102. Data in the control circuit 103 and disk cache memory 5 is transferred to the host system 3o via the SC3I hash 20. The control circuit 103 connects peripheral devices such as the disk device 8 connected to the disk cache control device IO to the device interface circuit 104.
control through the The small capacity buffer 102 temporarily stores the data read from the disk device 8 via the device interface circuit 104 in 1. 1.a The data is given to the microcomputer 101 and the disk cache memory 5.

FIG. 2 is a conceptual diagram showing the code format of a read command (RIEAD command) in 5C3I standardized by the ANS Ia committee. The constituent unit of the disk canon memory is called a block, and each block stores, for example, four words of data and management information thereof. The READ command consists of 6 heights and 0per
ation Code (08[1) is the read command (R
EAD) coat, Logicaltlnit Num
ber is the logical number of the disk device 8 connected to the disk cache control device 10, logicalBlock
Address is the logical block address of the sector on the disk where you want to start reading data, I'transfer
Leng Lh means the number of blocks to be read. Ven
dorUnique, Re5erved, Flag
, ink are not related to the present invention, so their explanation will be omitted.

Next, the operation of the disk cache will be explained.

When the host system 30 reads disk data,
A read command as shown in FIG. 2 is given to the disk cache control device 10 via the SC3I bus 20. The microcomputer 101 in the disk cache-based tall device 10 uses a Logical BLock Addr.
If the data exists in the disk cache memory 5, the read data is transferred to the host system 30 via the SC3I bus 20 based on the Transfer Length.

On the other hand, if the requested data does not exist in the disk cache memory 5, the microcomputer 101 gives an instruction to the control circuit 103, and the control circuit 103 gives a read command to the disk device 8 via the device interface circuit 104. At that time, the microcomputer 101
commands to continue outputting data twice the number of blocks specified by Transfer Length.

The sold data is temporarily stored in the small motherboard sofa 102 via the device ink face circuit 104. The microcomputer 101 sends this data to sc
Transfer to the host system 30 via the s r bus 20, but transfer to the SC3I bus 20 is via the Transfer L
The process ends when the data transfer of the data length specified by length is completed.

On the other hand, the Transfer read from the disk device 8
The data of double length rLengt+1 is transferred to the disk cache memory 5 and written.

In other words, data used in programs that are executed continuously is often stored in adjacent locations. Writing to the cache memory increases the probability that data expected to be used in subsequent processing exists in the disk cache memory, reducing access time.

Note that in this embodiment, Transfer Length
Although the configuration is such that data with a length twice as long as the specified number of blocks is read from the disk, the configuration is not limited to double the length, but may be configured to read multiple times in consideration of the capacity of the disk cache memory.

Further, in this embodiment, the disk cache in the SC3I has been described, but the present invention is not limited to this, and similar effects can be obtained with other interfaces.

〔Effect of the invention〕

According to the present invention, when reading data from a disk when no data exists in the disk cache memory,
By reading multiple blocks of data containing that data and writing them to the disk cache memory, the probability that the required data exists in the disk cache memory increases, the access time is shortened, and the performance of the disk cache is improved. be effective.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a disk cache control device according to the present invention, and FIG. 2 is a block diagram showing the configuration of a disk cache control device according to the present invention.
FIG. 3 is a conceptual diagram showing the code format of the D instruction. FIG. 3 is a block diagram showing the configuration of a conventional disk cache control device. 5... Disk cache memory 8... Disk device 10... Disk cache control device 20.
...5C8I bus 30...Host system 101
...Microcomputer 102...Small capacity bath sofa...Control circuit 104...Device interface circuit Note that in the figures, the same reference numerals indicate the same or equivalent parts. Agent Daiite Masuo

Claims (1)

[Claims] (1) A part of the data stored in the first storage means is stored in a second storage means that can be accessed faster than the first storage means, and the second storage means is searched preferentially. , if the required data does not exist in the second storage means, the first
In a storage device that reads data from a storage device, writes it in a second storage device, and transfers the required data to the outside of the device, means for reading data from the first storage device that is multiple times the data length to be transferred to the outside of the device; A storage device comprising means for writing the read data into a second storage means.