JPS61240320A - Magnetic disk controller - Google Patents

Abstract

PURPOSE:To shorten a downtime when a magnetic disk device has a trouble and to increase the executing speed of a double write command of data during a copying process, by providing an address counter, an address comparison part and a double write control part. CONSTITUTION:An address counter 23 stores the addresses within a magnetic disk device during an interrupted copying process. Thus an access can be given as normal from a central processor 10 even in a copy processing mode when the magnetic disk device has a trouble. This can shorten the downtime when the magnetic disk device has a trouble. An address comparison part 25 is added together with a double write control part 26. This part 26 decides whether data are written to the 1st magnetic disk device only or both magnetic disk devices. Thus the executing speed is increased a double write command of data during a copying process.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk control device, and particularly to a magnetic disk control device that controls copying of the contents of one of two magnetic disk devices to the other.

[Conventional technology]

In a dual-write system where the same content is written to two magnetic disk drives in case a magnetic disk drive fails, when a failure occurs in the first magnetic disk drive, the data is written to the other magnetic disk drive after repair. It is necessary to make a copy of the eye data. Conventionally, since the copying process was executed by the operating system, other job programs were unable to access the i-isk device while copying was in progress.

[Problem that the invention seeks to solve]

As a result, all jobs accessing the disk device are forced to wait from several minutes to several tens of minutes, resulting in a disadvantage that the system is essentially in a state similar to being down.

[Means for solving problems]

The magnetic disk control device of the present invention controls copying the contents of the first magnetic disk device out of two magnetic disk devices to the second magnetic disk device, and receives a double write command from the central processing unit. a copy control unit that temporarily suspends copying upon reception; an address counter that stores an address in the magnetic disk device during copying; and an address in the magnetic disk device and the address when a double write command is received from the central processing unit during copying. It is characterized by having an address comparison section that compares the magnitude of the counter, and a double-tooth control section that controls whether data is written to only one or both units based on the result of the address comparison.

In this way, by storing the address in the magnetic disk during the interrupted copying in the address counter, it becomes possible to access the address normally from the central processing unit even during the copying process when the magnetic disk device fails. By providing the comparison section and the double-tooth control section, the execution speed of the data duplication command during the copying process is improved.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of a magnetic disk control device according to the present invention.

The magnetic disk device interface control section 2 is an interface section with the magnetic disk devices 31 and 32. The central processing unit interface control section 21 is the central processing unit l.
This is an interface section with O. The write/read control unit 27 reads and writes the contents of the magnetic disk units 31 and 32 via the magnetic disk unit interface control unit 28. The copy control unit 22 receives copy commands from the central processing unit IO and transfers them to the central processing unit 10. When received via the interface control section 21, a command for copying from one of the magnetic disk devices 31, 32 to the other is output to the write/read control section 27. After the address counter 23 is set to an initial value by the copy control section 22, it is incremented by "1" every time one address is copied.

The address register 24 holds the address of the address counter 23, and also holds the address in the magnetic disk sent from the central processing unit 10 through the central processing unit interface control unit 21 when double teething is performed. Address comparison section 25 detects address counter 2 in case of double teeth.
3 and the contents of the address register 24 are compared. The double-tooth control unit 28 converts the data sent from the central processing unit IO to the write/read control unit 27 through the central processing unit interface control unit 21 based on the information from the address comparison unit 25, that is, the address of the address counter 23. If the address is smaller than the address in the address register 24, the data is written only to the magnetic disk device on the copying side.
If the address of the address counter 23 is larger than 7 addresses of the address register 24, the write/read control unit 27 is controlled so as to perform the double toothing as usual so as not to perform the double toothing.

Next, the operation of this embodiment will be explained.

Now, let us consider an example in which the magnetic disk device 32 has failed and data is to be copied after repair. When the copy control unit 22 recognizes a copy command from the central processing unit 10 through the central processing unit interface control unit 21, the copy control unit 22 transfers the data in the magnetic disk device 31 to the magnetic disk device 32 at a low address within the magnetic disk. (usually referred to as a cylinder address). The copy control unit 22 sets the initial value “oooo” in the address counter 23 and stores the contents of the address counter 23 in the address register 24.
is transferred to the magnetic disk device 3! through the magnetic disk device interface control section 28 to the write/read control section 27. The data at the address in the address register 24 is read from the address register 24 and is instructed to be written to the magnetic disk device M32. When the data of the magnetic f-isk device 32 is written to the magnetic disk device 31, the copy control unit 22 counts up the contents of the address counter 23 by “1”. Thereafter, in the same manner as described above, the data at the address in the address register 24 is read from the magnetic disk device 32 and the magnetic disk device 3
Instruct to write to 1. This operation is repeated until the final address, and finally all the contents of the magnetic disk drive 31 are copied to the magnetic disk drive 32. When all the data has been copied, the copy control unit 22 tells the central processing unit 10 to: Returns a copy command completion report and ends the series of processing.

Next, a process when the central processing unit 10 transfers data to the magnetic disk devices 31 and 32 in duplicate during this series of copying processes will be described. When a data duplication command is output from the central processing unit IO, the copy control unit 22 waits for the copying of the data in the address currently being copied to be completed, interrupts copying of the data in subsequent addresses, and then Starts processing of data duplication command. The address within the magnetic disk given by the data duplication command is transferred to the address register 24.

The double-tooth control unit 2B writes data given from the central processing unit W110 to the magnetic disk devices 31 and 32. At this time, data at addresses for which copying has not yet been completed in the interrupted copying process will be written from the magnetic disk device 31 to the magnetic disk device 32 when the copying process is restarted.

It is sufficient to write only to the magnetic disk device 31.

This makes it possible to increase the execution speed of the data duplex command. The address comparator 25 checks the address counter 23 to determine whether the address has not been copied yet.
(the address when copying was interrupted) and the address register 24 (the address given by the data double write command) are compared, and the result is sent to the double tooth control unit 28.
Report to. The double-tooth control unit 26 controls the address counter 2
3 is smaller than the address register 24, data is written only to the magnetic disk device 31, and the M control is performed so as not to perform double teeth. Do heavy teeth.

When the write process is completed, the copy control unit 22 receives the write completion report from the double-tooth control unit 2B, reports the completion of the data double write command to the central processing unit 10, and updates the interrupted copy process to an address. The process restarts from the 7th dress on the counter 23. When copying has been completed to the final address, the copy control unit 22 reports to the central processing unit 10 that the previously issued copy command has been completed.

Finish the series of processing.

In this embodiment, the instruction from the central processing unit IO during the copying process is a double-tooth instruction, but it is obvious that other instructions such as a read instruction can also be accepted.

Furthermore, in the embodiment described above, the copying process is interrupted in units of addresses within the magnetic disk.
The address comparison unit 25 can be simplified by interrupting the processing in units of addresses of a certain block, such as in units of 0 bytes. Furthermore, although the embodiment has been described in which the range of copying processing is all the data in the magnetic disk, it is also possible to easily specify the range to be copied using a copying command.

〔Effect of the invention〕

As explained above, the present invention performs control in which all data of a magnetic disk device is copied to another magnetic disk device within a magnetic disk control device, and also receives double-tooth commands from a central processing unit during the copying. By providing a copy control unit and an address counter that stores the magnetic disk address during copying and the address in the magnetic disk during copying that was interrupted at this time, it is possible to eliminate the problem in the event of a magnetic disk drive failure in a duplex system of magnetic disk drives. Even during the copying process, it can be accessed normally from the central processing unit.

This can substantially reduce downtime in the event of a magnetic disk device failure, and it also includes an address register that stores the address of the double-tooth command from the central processing unit and an address comparison unit that compares the value with the address counter. As a result, when copy processing is interrupted, if the address has not yet been copied, it is equipped with a double-tooth control unit that controls not to write to the failed magnetic disk device. This has the effect of improving the execution speed of the data duplex command being processed.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of a magnetic disk control device according to the present invention. lO... Central processing unit 20... Magnetic disk control device 21...
...Central processing unit interface control section 22
. . . Copy control unit 23 . . . Address counter 24 . . . Address register 25 .
...Address comparison section 2B...Double write control section 27...Write/read control section 28...
・・・・・・Magnetic disk device interface control unit

Claims (1)

[Claims] Copy control that controls copying the contents of the first magnetic disk device of two magnetic disk devices to the second magnetic disk device, and temporarily suspends copying when a double write command is received from the central processing unit. an address counter that stores an address within the magnetic disk device during copying; and an address comparison section that compares the address within the magnetic disk device when receiving a double write command from the central processing unit during copying with the size of the address counter. and a dual write control unit that controls whether to write data to only the first disk or to both disks based on the address comparison result.