JPS61224111A - Magnetic disc device - Google Patents

Abstract

PURPOSE:To improve the data transfer efficiency between a CPU and a magnetic disc by selecting an execution request with the nearest corresponding track position so as to control a disc thereby eliminating useless movement of a magnetic head. CONSTITUTION:When only one read/write execution request is held, a control signal is formed based on the read/write execution request held in a holding means 31 and the signal is outputted to a magnetic disc 2. When >=2 read/write execution requests are held, whether or not execution requests kept awaited for m-time or over exists is discriminated. If such request exists, the execution request kept waited for m-time is selected, the control signal is formed based on the said execution request and the result is outputted to a magnetic disc 2. When no such request exists, an execution request having the nearest track location from the present magnetic head position is selected out of the plural execution requests stored in the holding means 31, the control signal is formed based on the selected execution request and the result is outputted to the disc 2.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic disk device that improves the efficiency of data transfer between a central processing unit and a magnetic disk unit.

(Prior Art) FIG. 3 is a block diagram of a computer system having a magnetic disk device. In the figure, l is the central processing unit (hereinafter abbreviated as CPU), 2 is the disk unit, and 3 is the CPU.
A disk control device provided between the UI and the magnetic disk section 2 controls the magnetic disk section 2 based on signals from the CPUI. This disk control device 3 has a CPU
When read/write requests are sequentially sent to the magnetic disk unit 2, the address of the data to be accessed is converted into a device number, track number, head number, sector number, etc. in the order of the requests. The magnetic disk unit 2 consists of a disc recording medium that rotates at high speed and a magnetic head that faces the recording medium with a minute gap. First, move the magnetic head to the track containing the data to be read/written (position log), then wait for the disk to rotate until the first address arrives, and then perform the actual read/write operation (data transfer). It is now possible to do this.

Here, the registration time, the waiting time for one rotation, and the data transfer rate depend on the size of the device, but the following is an example.

(a) Bojishi snow two time Minimum 5ms Average 20m
5 Maximum 40m5 (C) Rotation waiting time Average 8.3m5 (C) Data transfer rate 1.3MB/sec There is a difference of 35m5 between the minimum and maximum positioning time when the magnetic head moves to a nearby track and when it moves to a far away track. This is the difference when moving to .

(Problem to be Solved by the Invention) For this reason, in the prior art, multiple read/write requests are made sequentially from the CPU to the disk unit 2, and the track position where data is located is located far away. In this case, the longer it takes to move the magnetic head and wait until a predetermined leading address arrives, the more the data transfer efficiency deteriorates.

The present invention has been made in view of such problems in the prior art, and its purpose is to eliminate unnecessary movement of the magnetic head and improve data transfer efficiency between the CPUI and the magnetic disk unit 2. We are trying to realize a magnetic disk device that can.

(Means for Solving the Problems) The present invention for solving the above-mentioned problems includes a central processing unit,
In an apparatus comprising a disk control device coupled to this central processing unit and a disk section controlled based on signals from this disk control device, read/line execution from the central processing unit is provided to the disk control device. holding means for holding a plurality of requests; and selection means for selecting an execution request whose corresponding track position is closest from among the plurality of execution requests held by the holding means based on the current magnetic head position of the disk unit. The disk control device is characterized in that it controls the disk unit based on the execution request selected by the selection means.

(Example) FIG. 1 is a block diagram of the configuration of an apparatus according to the present invention.

In the figure, 1 is a CPU, 2 is a magnetic disk unit, and 3 is a disk control device that controls the magnetic disk unit 2. This configuration is similar to that in FIG. In the disk control device 3, 31 is a holding means for holding a plurality of read/write execution requests (maximum n pieces) from the CPU 1, and for example, a song is used. Here, n is determined by specifying the maximum number of execution requests issued during a predetermined period of time. 32 is a magnetic head position signal output means for outputting a signal regarding the current position (track position) of the magnetic head of the disk unit 2; 33 is a signal input from the magnetic head position signal output means 32, and outputs a signal from the current magnetic head position. Judging and holding means 3
Selection means 34 selects the execution request whose track position to seek is closest to the current magnetic head position among the plurality of read/write execution requests held in 1; It is an output means for outputting a control signal to the magnetic disk unit 2 based on a write execution request.

Selection means 33. The output means 34 is configured using a microprocessor.

The operation of the apparatus constructed as above will now be explained with reference to FIG.

FIG. 2 is a flowchart showing an example of the operation of the disk control device 3. The disk control device 3 initially has K,
It is determined whether the disk device is processing the request or not in step l), and if it is not processing the request, the holding means 31! ! If it is determined that there is a request, the process moves to step 3. Here, the holding means 31 has two
Determine whether or not the above read/write execution requests are held (step 3). If only one read/write execution request is held (in the case of anol), proceed to step 2. Holding means Based on the read/write execution request held in 31, a control signal is generated and output to the magnetic disk unit 2. In step 3, if two or more read/write execution requests are held (#yes l).

Proceeding to step 5, here, it is determined whether there is an execution request that has been waited for 1m or more times among the two or more read/write execution requests, and if there is such an execution request (@y In the case of es @), the process moves to step 6, where the execution request that has been awaited m times is selected, a control signal is generated based on this execution request, and this is output to the magnetic disk unit 2.

In step 5, the execution request whose corresponding track position is closest to the current magnetic head position is selected among the plurality of execution requests that have been waited for m or more times;
Based on the selected execution request, a control signal is generated and output to the disk unit 2.

By such an operation, even when there are multiple execution requests, the time required for one position of the magnetic head in the magnetic disk unit 2 is always minimized, and the effective speed of data transfer can be improved. The flow in Figure 2 is when the CPUI issues a read/write request, and if the disk device has completed data transfer and is not doing anything, the timing is when the disk device has completed the read/write operation. will be activated.

(Effects of the Invention) As described above, according to the present invention, unnecessary movement of the magnetic head is eliminated, so a magnetic disk device that can improve data transfer efficiency can be realized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the configuration of the device of the present invention, and FIG. 7a shows an example of the operation of the disk control device in FIG. 1.
-Chart, FIG. 3 is a block diagram of the configuration of a computer system having a magnetic disk device. 1...CPU%2...Disk unit, 3...Disk control device, 31...Holding means, 32...Magnetic head position signal output means, 33...Selecting means, 34...
Output means. Agent Patent Attorney Shinsuke OzawaFigure 1Figure 3Figure 2

Claims (1)

[Scope of Claims] A device comprising a central processing unit, a disk control device coupled to the central processing unit, and a disk unit controlled based on a signal from the disk control device, wherein the disk control device includes: , a holding means for holding a plurality of read/write execution requests from the central processing unit, and a corresponding track among the plurality of execution requests held in the holding means as judged from the current position of the magnetic head of the disk unit. a selection means for selecting the execution request closest in position; and the disk control apparatus controls the disk unit based on the execution request selected by the selection means.