JPH02280221A - System for controlling disk - Google Patents

Abstract

PURPOSE:To improve a data processing speed by obtaining a time necessary for accessing the sector of an object and reading data from a disk device to take the shortest access time. CONSTITUTION:A cylinder address holding means 100 (registers 41 and 42) reads and holds the cylinder address of a recording medium 10 of disk devices 21 and 22 in which a magnetic head 13 is positioned at present. A rotary posi tion address detecting means 101 (interfaces 91 and 92) detects the rotary moving address of the recording medium 10 of the disk devices 21 and 22. An access time arithmetic means (access time arithmetic part 7) calculates a time necessary for accessing a sector 12 of the object on the recording medium from the cylin der address and rotary position address, and the data of the object are read form the disk device corresponding to the device having the shortest time calcu lated by the access time arithmetic means 7. Thus, the access time in the data read from the disk device can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a disk control method for selecting and controlling one of a plurality of disk devices.

[Conventional technology]

Traditionally, when a disk device fails in a computer system, the disk device becomes unusable.
A plurality of disk devices are provided that record the same data. Therefore, subsequent processing is performed using data from another disk device that replaces the failed disk device.

FIG. 4 is a block diagram for explaining a conventional disk control device. In FIG. 0, 1 is a disk device 21.2.
3 is a command processing unit provided in the disk control device I, 41.42 is a register also provided in the disk control device I, and 5 connects the disk control device 1 and the disk devices 21.22. a disk device interface bus, 6 is a disk control device 1;
and, for example, a host computer. The registers 41 and 42 correspond to the disk drives 2 in which respective magnetic heads (not shown) are located.
1.22 cylinder addresses of each recording medium (magnetic disk disk) are held. The above command processing section 3
The controller processes commands from the host computer to perform eight predetermined controls.

Next, the operation will be explained. The disk devices 21 and 22 are used in a master and submaster relationship, so it is assumed that the same data is recorded on both recording media as a prerequisite. First, the disk device 21 is connected from the host computer via the host interface bus 6.
Or, when a disk read command to read data from 22 is issued to the disk controller 1, the command processing unit 3 reads the cylinder address (the cylinder address where the magnetic head is currently located) that is the contents of the two registers 41 and 42. 0. For example, the value of register 42 is higher than the value of register 41. If the value is close to , the disk device 22 is selected, and the target data is sought through the disk device interface bus 5.
Waiting for the recording medium to rotate and data reading processing are executed.

[Problem to be solved by the invention]

Conventional disk control devices are configured as described above, so when two disk devices are used in a mask and submask relationship, the rotational waiting time of the recording medium is not taken into account, and either There is a problem in that it is difficult to determine whether it is fast to read data from a disk device, and therefore it is difficult to shorten the access time when reading data from a disk device in such a conventional disk control device.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a disk control method that can shorten the access time when reading data from a disk device.

[Means to solve the problem]

The disk control method according to the present invention currently has a magnetic head 1
The cylinder address holding means 100 (register 41.42) reads and holds the cylinder address of the recording medium 10 of the disk drive 21.22 where the disk drive 3 is located, and detects the rotational position address of the recording medium 10 of the disk drive 21.22'. The rotational position address detection means 101 (interfaces 91 and 92) determines the target sector on the recording medium 10 from the cylinder address held in the cylinder address holding means 100 and the rotational position address detected by the rotational position address detection means 101. 12, and reads data from the disk device corresponding to the shortest time calculated by the access time calculation means. It is characterized by:

[Effect]

Cylinder address holding means 100 (register 41.
42) is the disk device 2 where the magnetic head 13 is currently located.
The cylinder address of the recording medium 10 of 1.22 is read and held. The rotational position address detection means 101 (interfaces 91.92) detects the rotational position address of the recording medium 10 of the disk device 21.22.The access time calculation means (access time calculation unit 7) detects the rotational position address of the recording medium 10 of the disk device 21.22. The time required to access the target sector 12 on the recording medium IO is calculated from the address. Therefore, the target data is stored in the data whose time is the shortest as calculated by the access time calculation means (access time calculation unit 7). Read from the corresponding disk device.

[Embodiments of the invention]

FIG. 1 is a block diagram for explaining the configuration of a disk control system according to an embodiment of the present invention.

In FIG. 1, components corresponding to those in FIG. 4 are designated by the same reference numerals, and their explanations will be omitted. In Figure 1, 7
is the register 4 as the cylinder address holding means 100
1. An access time calculation unit as an access time calculation means that calculates the time required to access a target sector on each recording medium of the disk device 21.22 from the cylinder address held in 1.42 and the rotational position address below. be.

81 is a rotational position address bus for transmitting the rotational position address of the recording medium of the disk device 21 to the access time calculation section 7; 82 is a rotational position address bus for transmitting the rotational position address of the recording medium of the disk device 22 to the access time calculation section 7. It is a location address bus.

Reference numerals 91 and 92 designate interfaces as rotational position address detection means 101 for detecting the rotational position addresses of the recording media of the disk devices 21 and 22, respectively. FIG. 2 is a block diagram of a recording medium (magnetic disk) provided in the disk device 21, 22, where 10 is a recording medium, 11 is a cylinder, 12 is a sector, and 13 is a magnetic head.

Next, the operation of this embodiment will be explained with reference to FIGS. 1 and 2. The disk controller 1 is connected from a host computer (not shown) via a host interface bus 6.
When a disk read command is issued to read data from the disk device 21 or 22, the command processing unit 3
The two disk devices 2 are connected to the access time calculation unit 7.
1. A request is made to calculate the access time to the target sector 12 of each recording medium 10 of 1.22 degrees. As a result, the access time calculation section 7 receives the rotational position address of each disk device 21.22 sent from the interface 91.92 through the rotational position address bus 81.82, and the cylinder address that is the content of the register 21.22. is used to calculate the access time to the target sector 12 by the magnetic herad 13, and the result is returned to the command processing section 3.

Therefore, the command processing unit 3 selects the disk device with the shorter access time to the target sector 12, and executes data seek processing, waiting for rotation of the recording medium 10, and data reading processing.

In the above embodiment, two disk devices are connected, but as shown in FIG. 3, three disk devices or four or more disk devices may be connected.

〔Effect of the invention〕

As described above, according to the present invention, the rotational position address of the recording medium is read from a plurality of disk devices, and the time required to access the target sector is determined based on the rotational position address and the cylinder address where the magnetic head is currently located. Since the data is read from the disk device that requires the shortest access time, the access time for reading data from the disk device can be shortened and the data processing speed can be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram for explaining the configuration of a disk control system according to an embodiment of the present invention, FIG. 2 is a diagram for explaining the configuration of a recording medium of a disk device in this embodiment, and FIG. 3 4 is a block diagram for explaining the configuration of a disk control device according to another embodiment, and FIG. 4 is a block diagram for explaining the configuration of a conventional disk control device. DESCRIPTION OF SYMBOLS 1... Disk control device, 7... Access time calculation part (access time calculation means), 1o... Recording medium, 1
1... Cylinder, 12... Sector, 13... Magnetic head, 21, 22. 23... Disk device, 41,
42.43...Register (cylinder address holding means), 9192.93...Interface (rotational position address detection means), 100...Cylinder address holding means, 101...Rotational position address detection means.

Claims (1)

[Claims] In a disk control device that selects multiple disk drives that record the same data and controls the reading of data from the selected disk drives, reads the cylinder address on the recording medium of the disk drive where the magnetic head is currently located. a cylinder address holding means for holding a rotational position address, a rotational position address detection means for detecting a rotational position address of a recording medium of the disk device, and a cylinder address held in the cylinder address holding means and the rotation detected by the rotational position address detection means. access time calculation means for calculating the time required to access a target sector on the recording medium from the position address, and data from the disk device corresponding to the shortest time calculated by the access time calculation means. A disk control method characterized by reading.