JPS62288926A - Magnetic disk access control system - Google Patents

Abstract

PURPOSE:To improve the processing efficiency of read/write by storing a new address of a magnetic head in a magnetic disc device by an instruction judging circuit of an adapter simultaneously with completion of the read/write operation to the record of a certain track by the magnetic disk device. CONSTITUTION:When a disk controller 10 sends a set head address register HAR no-oriented instruction prepared by a command sending circuit 11, an adapter 12 causes an instruction judging circuit 13 to analyze this instruction. The set HAR instruction is executed in the read/write mode to store the address of the magnetic head in a register of a magnetic disc device 5. Thus, selection of the magnetic head is momently completed to immediately execute the read/ write to the record of another track from one track.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Summary] Tracks belonging to the same cylinder of a magnetic disk can be quickly transferred from one track to another by selecting a magnetic head based on an address. Since the record can be accessed, the address of the magnetic head can be stored in the register of the magnetic disk device while maintaining the read/write mode between the adapter and the magnetic disk device.

[Industrial application field]

The present invention relates to a magnetic disk subsystem, and particularly to a magnetic disk access control method that improves the efficiency of read/write processing involving seek head (selection of magnetic heads for tracks on the same cylinder) operation.

A magnetic disk subsystem is constructed by connecting an adapter to a magnetic disk control device, and connecting a plurality of magnetic disk devices to this adapter. The magnetic disk control device receives a seek command and read/write command from the host device, selects a magnetic disk device via the adapter, and selects a magnetic disk device.
After the magnetic head is positioned at the target cylinder, the magnetic head is selected by a seek head command and data write/write operations are performed on the target track of the cylinder.

As shown in FIG. 6, data is recorded on the track in the order of record numbers, so following the index 6 indicating the beginning of the track, there is a home address 11A indicating the physical position of the track on the magnetic disk, followed by the record number. are recorded in numerical order from 0 to N.

Each record is divided into a count section and a data section, with the 0th record consisting of a count section ROC and a data section ROD, and the 1st record I' consisting of a count section RIG and a data section RID.

Therefore, when reading/writing a record on one track and then reading/writing a record on another track on the same cylinder, the seek head command causes the magnetic disk controller to read/write the record on the magnetic disk drive. The node address is selected.

At this time, the adapter is connected to the set H from the magnetic disk controller.
In response to a command called AR (head address register), the address of the magnetic head is stored in the register of the magnetic disk device, and the selection of the magnetic head is performed.

That is, in a magnetic disk device, a set HAR command is used to refer to the magnetic node address stored in a register for multiple tracks existing in the same cylinder.
Select a magnetic head to read/write data.

In this case, all magnetic heads are positioned on tracks belonging to the same cylinder, and the address of the magnetic head changes when reading/writing data from one track to reading/writing data from another track. 1. This can be implemented, but it is necessary that the read/write processing efficiency is good at this time.

[Conventional technology]

FIG. 4 is a block diagram illustrating the conventional technology.

The central processing unit 1 sends a seek head command and a read/write command to the magnetic disk controller 3 via a channel 2. When the magnetic disk control device 3 analyzes this command and finds that it is a track selection within the same cylinder, it causes the magnetic disk device 5 to select a magnetic head via the adapter 4.

The magnetic disk controller 3 switches the address of the magnetic head using the set HAR command issued during read/write and the set T(AR) command issued during read/write.
Normal magnetic head address switching is performed by setting H immediately before starting read/write.
This is done by issuing an AR command.゛For this reason, if a seek head command is chained following a read/write command given from channel 2, the magnetic disk control device 3 will, for example, read another record from the third record of the track shown in FIG. Assuming that an instruction is given to read/write the fourth record of the track, following the read/write command for the third record, a reset read/write is sent to the adapter 4, and a magnetic A process for dropping the read/write mode for the disk device 5 is performed.

Next, the magnetic disk control device 3 sends a MAR command to the adapter 4, records the address of the magnetic head in the register of the magnetic disk device 6, and then sends a set read/write to the adapter 4. A read/write for the magnetic disk device 5 to the adapter 4.
After performing processing to raise the write mode, the next read/write command is sent to read/write the fourth record.

[Problem that the invention seeks to solve]

As described above, conventionally, when executing a seek head command, the read/write mode between the adapter and the magnetic disk device is temporarily canceled, which makes the command sequence complicated and time-consuming.

Therefore, in order to read/write from the third record of one track to the fourth record of another track as described above, it is necessary to switch the magnetic head at the gap that exists between records. Since the switching time of the magnetic head is long, there is a problem in that the switching time is not enough and the magnetic disk has to wait for rotation, reducing read/write processing efficiency.

c.Means for solving problems] FIG. 1 is a block diagram of the principle of the present invention.

The command sending means 11 of the magnetic disk controller fIO is activated at any time during read/write))! , A.R.
A set HAR no-oriented command that can execute the command is prepared, and when the adapter 12 receives this set HAR no-oriented command, the command determination means 13 analyzes this command and sets the read/write mode to the magnetic disk device 5. Does not perform processing to drop the 8-do.

The adapter 12 is configured to execute a set HAR command that stores the address of the magnetic head in the register of the magnetic disk device.

[Effect]

With the above configuration, the magnetic disk control device 10
By sending the set HAR no-oriented command prepared by the command sending means 11, the adapter 1
2 causes the command determination means 13 to analyze this command,
By executing the set HAR command while maintaining the read/write mode, the address of the magnetic head is stored in the register of the magnetic disk device 5, and the selection of the magnetic head is instantaneously completed. You can read/write the record immediately.

〔Example〕

FIG. 2 is a block diagram of a circuit showing one embodiment of the present invention.

The microprocessor 17 of the magnetic disk control device 10 operates by reading the program stored in the control memory 18, analyzes commands from the channels that enter through the interface control circuit 14, and executes the commands from the interface control circuit 16.
The command is sent to the adapter 12 via the .

In addition, data entering via the interface control circuit 14 is
Controls the data transfer control circuit 15 and sends the data to the adapter 12 via the interface control circuit 16.
Data entering via the interface control circuit 16 from
The data transfer control circuit 15 is controlled and the data is sent from the interface control circuit 14 to the channel.

The microprocessor 24 of the adapter 12 is connected to a magnetic disk control bag W10 that enters via the interface control circuit 19.
The interface control circuit 22
The command is sent to the magnetic disk device via the .

Furthermore, the data that enters via the interface control circuit 19 is
Data sent from the interface control circuit 22 to the magnetic disk device via the data transmission control circuit 20 and read from the magnetic disk device is sent to the interface control circuit 22.
, data transfer control circuit 20, interface control circuit 1
9 and then sent to the magnetic disk control device 10.

During this data transfer, the ECC control circuit 21 detects data errors and corrects correctable errors.

When interlocking with other adapters, the cross-call control circuit 23 performs exclusive control so that the same magnetic disk device is not coupled to two magnetic disk control devices.

FIG. 3 is a command sequence explaining the operation of FIG. 2.

If a seek head command is received from a channel or is chained to a read/write command, the microprocessor 17 sets H while executing a read/write command.
The AR no-oriented command is sent to the microprocessor 24 of the adapter 12 via the interface control circuit 16 and the interface control circuit 19.

When the microprocessor 24 analyzes this set HAR no-oriented command, it maintains the read/write mode for the magnetic disk device, and at the same time as the read/write operation for the record of a certain track that is being read/written is completed, the In order to switch the head address, the address of the magnetic head is stored in the register of the magnetic disk device via the interface control circuit 22.

Microprocessor 17 then sends the next read/write command to microprocessor 24, which begins executing the read/write command for the specified record of the new trunk.

〔Effect of the invention〕

As described above, the present invention can improve read/write processing efficiency when there is a seek head command chained to a read/write command.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the principle of the present invention, Fig. 2 is a block diagram of a circuit showing an embodiment of the present invention, Fig. 3 is a command sequence explaining the operation of Fig. 2, and Fig. 4 is a conventional technique. FIG. 5 is a block diagram illustrating the operation of FIG. 4, and FIG. 6 is a diagram illustrating an example of a trunk. In the figure, 1 is a central processing unit, 2 is a channel, 3.10 is a magnetic disk controller, 4.12 is an adapter, 5 is a magnetic disk device, 1
1 is a command sending means, 13 is a command determining means, 14.16, 19.22 is an interface control circuit, 1
5.20 is a data transfer control circuit, 17.24 is a microprocessor, 1B is a control memory, 21c [ICCwJ[liW,
23 is a cross call control circuit. A block diagram of a circuit showing an embodiment of the present invention.A command sequence explaining the operation of FIG. 2.FIG.

Claims (1)

[Claims] In a magnetic disk subsystem comprising a magnetic disk control device (10), an adapter (12), and a magnetic disk device (5), the magnetic disk control device (10) includes an adapter (12) and a magnetic disk device (5). Command sending means (11) that sends a command that makes it possible to send the address of the magnetic head while maintaining the read/write mode between the disk devices (5).
The adapter (10) analyzes the command and makes a decision to store the address of the magnetic head in the register of the magnetic disk device (5) while maintaining the read/write mode with the magnetic disk device (5). Means (13) is provided, and when the magnetic disk controller (10) receives a seek head command chained to a read/write command, the command sending means (11) sends the command to the adapter (12), and the adapter (12) sends the command to the adapter (12). 12) Command determination means (13)
is a magnetic disk access control method characterized by storing a new address of a magnetic head in a register of a magnetic disk device (5) at the same time that the magnetic disk device (5) completes a read/write operation for a record on a certain track. .