JPS6224405A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To improve a write/verity speed and responsiveness with multicall constitution by providing plural head drive mechanisms, a control circuit and a control part giving commands from plural CPUs independently to the control circuit. CONSTITUTION:At the time of a write/verity action, a data reading action with respect to a disk 25 follows data writing on the disk 25 after the half the rotation, and the data is compared by the control part 11, whereby the data to be written on the disk is quickly checked. The reliability of the write data is improved by less overheads. At the time of a parallel access action, the time waiting other CPUs' accesses in terms of one CPUs' access is eliminated because two independent disk access mechanisms and circuits can be used, and accordingly the responsiveness as one system can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic disk device suitable for write/verity operations and parallel access operations.

[Problems of Background Art] Conventionally, a magnetic disk device has a configuration as shown in FIG. The magnetic disk device consists of a magnetic disk control device 1 and a magnetic disk drive 2. The magnetic disk wJ device 1 has a control section 11 and a buffer 12. The magnetic disk drive 2 has a control circuit 21 , a head drive device 22 , and a head arm 23 driven by the head drive device 22 .
A head 24 for reading and writing data on the magnetic disk 25 is attached to the tip of the magnetic disk 25 . The boat 111 of the control unit 11 of the magnetic disk control device 1 is connected via the channel 3 to the system bus 4 of one system in total. A CPU 5, a main storage device 6, etc. are connected to this system bus 4. In addition, the boat 1 of the control section 11
12 is connected to other computer systems.

When the control unit 11 of the magnetic disk control device 1 receives an instruction from the CI (IJ) 5 via the channel 3, the control unit 11 instructs the control circuit 21 of the magnetic disk drive 2 to
Issues magnetic disk head movement commands and data write or read commands. When the control circuit 21 of the magnetic disk drive 2 receives a head movement command, it instructs the head drive device 22 to perform a head seek operation. Thereby, the head driving device 22 operates the head arm 23 to move the head 24 to the desired position. Thereafter, when the magnetic disk drive 2 receives a write or read command, data is transferred between the magnetic disk 25 and the main storage device 6 via the control circuit 21, the control unit 11, the buffer 12, and the channel 3. .

Note that the control unit 11 of the magnetic disk control device 1 is connected to port 1.
It is possible to receive commands from the CPUs of other computer systems via the CPU 12, and when a command is received, operations similar to those described above can be performed with other computers.

[Problems with Background Art] The conventional magnetic disk device as described above has the following drawbacks during write/verity operation to check whether write data has been correctly written. That is, after writing data to the disk, the CPU 5
In addition, in order to reread the written data, the disk must again perform a seek operation and wait for rotation, which takes time. Therefore, quick write/verity operations could not be performed.Furthermore, an area for rereading written data is required in addition to an area for writing data on the main storage device 6, and the raw storage device 6 is As the capacity increases, this check is performed by the CPU 5, which has the disadvantage of increasing the load on the CPLJ 5. Furthermore, it is difficult to use in a multicall configuration where one magnetic disk drive is accessed by two or more CPUs. Sometimes, while one CPU is accessing the disk, other CPUs are unable to access the disk, which has the drawback of reducing the responsiveness of the system.

[Object of the Invention] In view of the above-mentioned drawbacks, an object of the present invention is to provide a magnetic disk device that can improve the write/verity operation speed (as well as improve responsiveness when used in a multi-call configuration). Our goal is to provide the following.

[Summary of the Invention 1] The present invention provides a magnetic disk drive with a plurality of head drive mechanisms that move a plurality of heads to predetermined positions on the disk, and a control circuit that independently controls these head drive mechanisms; , the magnetic disk control device is capable of processing read and written data by each of the heads independently, and can independently give commands from a plurality of CPUs to the control circuit, and further allows the data written by one head to be processed by another The above object is achieved by providing a control section that can immediately read out the data using the head of the first embodiment, compare both data, and detect discrepancies and CRC errors.

[Embodiment 1 of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings, in which the same parts as those of the conventional example are denoted by the same reference numerals. FIG. 1 is a block diagram showing an embodiment of a magnetic disk device of the present invention.

The magnetic disk device consists of a magnetic disk control device 1 and a magnetic disk drive 2. The magnetic disk control device 1 has a control section 11 and buffers 12 and 13. The magnetic disk drive 2 includes a control circuit 21.26, head drive devices 22, 27, and this head drive device 22.2.
Head arms 23 and 28 each driven independently at 7
Furthermore, heads 24 and 29 for reading and writing data on the magnetic disk 25 are attached to the tips of these head arms 23 and 28. A port 111 of the control unit 11 of the Ia disk control device 1 is connected to a system bus 4 such as a 1FLL system via a direnel 3. This system bus 4 has CPLJ 5.
and a main storage device 6 etc. are connected thereto. A port 112 of the control unit 11 is connected to another 81 machine system (not shown).

Next, the operation of this embodiment will be explained. The operations of the magnetic disk drive 2 can be broadly classified into the following two types. That is, (
1) data write/verity operation mode; and (2) disk alignment 1] access (in multicall configuration) operation mode. These operating modes can be instructed from the CPU 5, and when accessing the disk, a command is issued to the magnetic disk control system 1 via the channel 3.

First, (1) the disk read/verity operation mode will be explained. Magnetic disk drive 2 from CPU5
When a write/verity command is issued to the disk 25, this command is given to the control section 11 of the magnetic disk control device 1 via channel T7. The control unit 11 is a CP
Deciphers the instructions from U5 and activates the magnetic disk drive 2.
At the same time, a head movement instruction is issued to the control circuits 21 and 26 that constitute the. The control circuit 21.26 moves the head drive device 22.27 based on the head movement instruction, and moves the head 24.29 attached to the tip of the head arm 23.28 to the desired position. During this time, the control unit 11 of the magnetic disk controller 1 fetches write data from the main storage device 6 via the channel 3 into the buffer 12.When the disk head seek is completed, the control unit 11 of the magnetic disk controller 1 reads the write data from the main storage device 6 via the channel 3. issues a command to the control circuit 21 of the magnetic disk drive 2 to write the contents of the buffer 12 to the disk 25, and at the same time
Buffer 1 to control circuit 26 with a delay of half a rotation of
A command is issued to read the contents of the disk 25 to the third disk, and the data written to the disk 25 via the control circuit 21 is
The data can be read through the control circuit 26 with a delay of half a rotation. Next, the control unit 11 of the magnetic disk control device 1 compares the contents of the discs 12 and 13 in order from the data for which writing/rereading has been completed, and checks that the data has been correctly written to the disk 25. In this comparison, data match or CR of buffer 12.13
If a C error is detected, the control unit 11 notifies the CPU 5 of this and ends the data write/reread process.

Next, the disk parallel access operation mode will be explained. The magnetic disk drive 2 of this example includes heads 24 and 29 attached to head arms 23 and 28 that can each operate independently. For this reason, a disk access request from the CPU 5 is sent to the buffer of the control unit 11 of the magnetic disk control device 1. 12 to access the disk 25 via the control circuit 21 and head 24 of the magnetic disk drive 2. A disk address request from the other CPU (not shown) is
Buffer 13 of magnetic disk control unit 10 control unit 11
The control circuit 26 of the magnetic disk drive 2 uses the control circuit 26. This is executed by accessing the disk 25 via the head 29. Therefore, disk access requests from two CPUs can be made in parallel. According to this embodiment, data writing and reading operations to the disk 25 can be performed with a half rotation delay during the write 1~/verity operation, and by comparing these data in the control unit 11. , it is possible to quickly check the data in and out of the disk, and the reliability of old data can be improved with less overhead. In addition, during parallel access operation, two independent systems of disk access mechanisms and circuits can be used, so when one CPU accesses, other CPUs
U's access time etc. are eliminated, and the responsiveness of the system can be improved. In addition, head 2 in Fig. 1
By arranging the /I and 29 as close as possible, the delay time from writing to reading can be minimized.

In addition, the above-mentioned effect is not obtained when two heads are installed on the same head arm (a pull system is easily considered, but in this case they are parallel). In addition, in the parallel access operation mode, in the example shown in FIG.
, 112. However, if the magnetic disk control device 1 manages the requests of each CPU and the access status of the magnetic disk drive 2, and also controls the Samurai, 3.
It is also possible to enable access from the CPU on the machine, and in this case as well, the overall responsiveness can be improved. Furthermore, when parallel access is performed by three or more CPUs, the number of buffers in the magnetic disk drive control circuit 1 is increased, and the control circuit, head drive device, and head of the magnetic disk drive 2 are adjusted accordingly. It is also possible to have an increasing configuration.

[Effects of the Invention] As described above, according to the magnetic disk dead end of the present invention,
The magnetic disk drive is provided with a plurality of head drive mechanisms that move a plurality of heads to predetermined positions on the disk, and a control circuit that independently controls these head drive mechanisms. Read and process old data independently, and
A control unit capable of independently giving commands from the LI to the control circuit, and further capable of immediately reading data written by one head by another head, comparing these data, and detecting mismatches and CRC errors. By providing this, it is possible to improve the write/verity operation speed and to improve responsiveness when used in a multi-call configuration.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a magnetic disk device of the present invention, and FIG. 2 is a block diagram showing an example of a conventional magnetic disk device. 1... Magnetic disk control device 2... Magnetic disk drive 5... CPU 11... Control unit 12, 1
3... Buff? 21.26...Control circuit 22
, 27...Head drive device 2 3, 28...Head arm 24, 29...Head 25...Disk agent Patent attorney Book 1) Takashi Figure 1 Figure 2

Claims (1)

[Claims] A magnetic disk drive has a plurality of head drive mechanisms that independently move a plurality of heads to predetermined positions on one disk, and a control circuit that independently controls each of these head drive mechanisms, and a magnetic disk drive that receives commands from a plurality of CPUs. The control circuit is configured to cause each head to independently read and write data on the disk, read data written by one head using another head, and compare both data to ensure that the data is correctly written. What is claimed is: 1. A magnetic disk device comprising: a magnetic disk control device having a control unit that checks whether the data has been read or not.