JPH01188966A - Magnetic disk controller containing cache - Google Patents

Abstract

PURPOSE:To write even the data on the physical record stored in a store-in cache block only with a partial logical record into a magnetic disk by storing the data on the physical code read out of the disk into a buffer and then reading the partial physical record out of a cache memory to replace it. CONSTITUTION:A magnetic disk controller contains a host processor 10, a magnetic disk 20, and a microprocessor 40 which controls the transfer of data to a cache memory 30. The processor 40 is connected to a cache data reading means 50 which reads the data out of the memory 30 as well as to a data writing means 60 which writes data into the disk 20 and a data reading means 70 which reads data out of the disk 20 respectively. A data buffer 80 stores the data read out of the disk 20 by the means 70 and the data read out of the memory 30 by the means 50 and then sends these data to the means 60.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk control device with a cache, and more particularly to a disk control device with a cache that writes store-in data, in which data is stored only in a cache memory, to a magnetic disk. .

[Conventional technology]

Conventionally, this type of magnetic disk controller with cache stores data in cache blocks for each physical record, and when writing store-in data to a magnetic disk, it also stores data for each physical code. It was like that.

[Problem to be solved by the invention]

The above-mentioned conventional magnetic disk controller with cache processes each physical record, so only some of the logical records of a physical record consisting of multiple logical records are stored in the store-in cache block. In this case, there is a drawback that store-in data cannot be written to the magnetic disk without rewriting the data stored in the magnetic disk corresponding to the logical record portion that is not stored in the cache block.

[Means to solve the problem]

A magnetic disk control device with a cache according to the present invention is a magnetic disk control device provided between a host processor and a magnetic disk in which a plurality of files are stored in a fixed length. a cache memory for storing data; a cache data reading means for reading data from a physical record or reading data from a part of the logical records, which is composed of a plurality of logical records stored in the cache memory; a data reading means for reading, and storing data of a physical record read from the magnetic disk by the data reading means,
a data buffer for storing data of physical records updated with data of some logical records in the cache memory read by the cache data reading means; and data writing means for writing physical record data or data stored in the data buffer onto the magnetic disk.

〔Example〕

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

FIG. 1 is a block diagram showing an embodiment of the present invention. 1st
In the figure, one embodiment of the present invention is shown in host processor 10.
and a magnetic disk 20 that stores a plurality of files, and has a cache memory 30 that stores files given according to instructions from the host processor 10. This magnetic disk control device has a microprocessor 40 that controls data transfer between a host processor 10, a magnetic disk 20, and a cache memory 30.
data writing means 60 and magnetic disk 2 connected to cache data reading means 50 for reading data stored in 0 and writing data to magnetic disk 20;
It is connected to data reading means 70 for reading data from 0.

The data buffer 80 is configured to store data read from the magnetic disk 20 by the data reading means 70 and data read from the cache memory 30 by the cache data reading means 50, and to send the data to the data writing means 60. There is.

First, from the host processor 10 to the cache memory 30
When the instruction 100 to write the data of the store-in cache block stored in the store-in cache block to the magnetic disk 10 is sent, the microprocessor 40 writes the data of the logical record consisting of a plurality of logical records to the store-in cache block completely. Check to see if it is remembered.

If all the logical records in the physical record are stored in the store-in cache block, the microprocessor 40 issues instructions 110 and 120 to the cache data reading means 50 and data writing means 60, respectively.
9 The cache data reading means 50 issues an instruction 110.
When receiving the data, the data of the physical record is read from the cache memory 30 via the bus 200 and outputted to the data writing means 60 via the bus 210. Data drafting means 6
0 becomes 1 due to the instruction 120 from the microprocessor 40.
．． The physical record data output from the cache data reading means 50 is transferred to the magnetic disk 2 via the bus 220.
Write to 0.

Next, if only part of the logical record in the physical record is stored in the store-in cache block, the microprocessor 40 first issues an instruction 130 to the data reading means 70. The data reading means 70 reads the instruction 13
When 0 is received, the data of the physical record is read from the magnetic disk 20 via the bus 230 and stored in the data buffer 80 via the bus 240. The microprocessor 40 then issues an instruction 110 to the cache data reading means 50. Cache data transfer means 5 receives instruction 11
When 0 is received, data of some logical records stored in the cache memory 3 is read out via the bus 200,
A part of the data of the physical record read from the magnetic disk 2 stored in the data buffer 8 via the bus 250 is updated. Next, the microprocessor 40 issues an instruction 120 to the data writing means 60. Instructions 120
Accordingly, the data writing means 60 reads the data of the physical record stored in the data buffer 80 via the bus 260 and writes it to the magnetic disk 20 via the bus 220.

〔Effect of the invention〕

As explained above, the present invention stores data of a physical record read from a magnetic disk in a data buffer, and stores data of a logical record of a part of the physical record stored in a store-in cache block in a cache memory. By updating the read data buffer and writing it to the magnetic disk as follows, it is possible to write the data of the physical record, in which only some logical records are stored in the store-in cache block, to the magnetic disk.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 10... Host processor, 20... Magnetic disk, 30... Cache memory, 40... Microprocessor, 50... Cache data reading means, 6
0...Data writing means, 70...Data reading means, 80...Data buffer.

Claims (1)

[Claims] In a magnetic disk control device connected to a host processor and a magnetic disk storing a plurality of fixed-length files, a cache memory stores files given in accordance with instructions from the host processor, and a cache memory stores files in the cache memory. a cache data reading means for reading data of a physical record consisting of a plurality of logical records, or reading data of a part of the logical records; a data reading means for reading data from the magnetic disk; and the data reading means. storing the data of the physical record read from the magnetic disk by;
a data buffer for storing data of physical records updated with data of some logical records in the cache memory read by the cache data reading means; and a data buffer in the cache memory read by the cache data reading means. physical record data,
or a data writing means for writing data stored in the data buffer to the magnetic disk.