JPH0628045B2 - Magnetic disk controller with cache - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk controller with a cache, and more particularly to a disk controller 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, a magnetic disk controller with a cache of this kind stores data in a cache block for each physical record. Even when writing store-in data to a magnetic disk, write data for each physical record. It was.

[Problems to be Solved by the Invention]

Since the conventional magnetic disk control device with a cache described above processes each physical record,
When only some of the logical records of the physical records consisting of multiple logical records are stored in the cache block for store-in, the data stored in the magnetic disk corresponding to the logical record part not stored in the cache block There is a drawback that the store-in data cannot be written to the magnetic disk without rewriting.

[Means for Solving the Problems]

A magnetic disk controller with a cache according to the present invention is a magnetic disk controller provided between a host processor and a magnetic disk that stores a plurality of files in a fixed length, and stores a file given by an instruction of the host processor. A cache memory for storing data, a cache data reading unit for reading data of a physical record consisting of a plurality of logical records stored in the cache memory, or a part of the logical record, and data from the magnetic disk. And data of a physical record read from the magnetic disk by the data reading means, and data of a part of the logical record in the cache memory read by the cache data reading means. Physical record updated by And a data buffer for storing the data of the physical record in the cache memory read by the cache data reading means or the data stored in the data buffer to the magnetic disk. have.

〔Example〕

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

FIG. 1 is a block diagram showing an embodiment of the present invention. First
Referring to the drawings, one embodiment of the present invention is a host processor 10.
And a magnetic disk 20 for storing a plurality of files, which is a magnetic disk control device, and has a cache memory 30 for storing the files given by the instruction of the host processor 10. This magnetic disk control device has a microprocessor 40 for controlling data transfer between the host processor 10, the magnetic disk 20, and the cache memory 30, and the cache memory 3
The magnetic disk 2 and the data writing means 60 connected to the cache data reading means 50 for reading the data stored in 0 and writing the data to the magnetic disk 20.
It is connected to a data reading means 70 for reading data from 0. The data buffer 80 is a data reading means 7
0 is the data read from the magnetic disk 20 and the cache memory 3 by the cache data reading means 50.
The data read from 0 is stored and the data writing means 6
It is configured to send to 0.

First, from the host processor 10 to the cache memory 30
When a command 100 for writing the data of the store-in cache block stored in the magnetic disk 10 to the magnetic disk 10 is sent, the microprocessor 40 completely stores the data of the logical record composed of a plurality of logical records in the store-in cache block. Check if it is remembered.

When all the logical records in the physical record are stored in the cache block for store-in, the microprocessor 40 instructs the cache data reading means 50 and the data writing means 60, respectively.
Give out. The cache data reading means 50 gives an instruction 110.
When the data is received, the data of the physical record is read from the cache memory 30 via the bus 200 and output to the data writing means 60 via the bus 210. Data drafting means 6
0 is an instruction 120 from the microprocessor 40,
The physical record data output from the cache data reading means 50 is transferred to the magnetic disk 20 via the bus 220.
Write to.

Next, when only a part of the logical record in the physical record is stored in the cache block for store-in, the microprocessor 40 first issues the instruction 130 to the data reading means 70. The data reading means 70 uses the instruction 13
When 0 is received, the data of the physical record from the magnetic disk 20 is read out via the bus 230 and stored in the data buffer 80 via the bus 240. Next, the microprocessor 40 issues an instruction 110 to the cache data reading means 50. The cache data transfer means 5 gives an instruction 11
When 0 is received, some logical record data stored in the cache memory 3 is read 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. Instruction 120
Thus, the data writing unit 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.

〔The invention's effect〕

As described above, according to the present invention, the data of the physical record read from the magnetic disk is stored in the data buffer, and the data of a part of the logical record of the physical record stored in the cache block for store-in in the cache memory is stored. By updating the data in the read data buffer and then writing the data to the magnetic disk as described below, the data of the physical record in which only some of the logical records are stored in the store-in cache block can be written to the magnetic disk.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention. 10 ... Host processor, 20 ... Magnetic disk, 30 ...
Cache memory, 40 ... Microprocessor, 50 ...
Cache data reading means, 60 ... Data writing means, 70 ... Data reading means, 80 ... Data buffer.

Claims (1)

[Claims] 1. A magnetic disk controller connected to a host processor and a magnetic disk stored in a fixed length of a plurality of files, a cache memory for storing a file given by an instruction of the host processor, Cache data reading means for reading data of a physical record consisting of a plurality of logical records stored in the cache memory or reading data of a part of the logical records; and data reading means for reading data from the magnetic disk. A physical record updated by the data of a part of the logical record in the cache memory read by the cache data reading means, in which the data of the physical record read by the data reading means is stored. Data buffer to store the data of Serial magnetic disk controller with a cache and a data writing means for writing the read physical record of the data in the cache memory, or the data stored in the data buffer to the magnetic disk by the reading means of the cache data.