JP2737555B2 - Disk controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk controller for controlling a disk drive having a data plane offset function for improving the positioning accuracy of a head, and more particularly to a disk control apparatus for correcting the position of the head by using the data plane offset function. The present invention relates to a disk control device capable of reliably executing a patrol servo command for collecting an offset amount to be performed.

In response to the demand for high-density recording for disk devices, as the recording density of tracks increases, it has been required to improve the positioning accuracy of heads relative to tracks.

Therefore, when positioning each head on a designated track based on the servo information read from the servo surface, the displacement of each head from the center of the track is determined by the offset amount collected by the data surface offset function. A disk device for correcting each is provided.

By the way, the data surface offset function is to read the servo information recorded on the data surface at predetermined intervals to measure the offset amounts of all the heads, and use this offset amount to perform servo control. This is a function of positioning each head at the center of the track by correcting the positional deviation from the center of the track when the head is positioned based on the servo information read from the surface.

Therefore, in order to always accurately position the head at the center of the track, this offset amount needs to be the latest.

[0006]

2. Description of the Related Art FIG. 5 is a block diagram for explaining an example of the prior art, and FIG. 6 is a detailed block diagram of each functional unit.

In FIG. 5, the disk controller 2 is composed of a plurality of functional units. The channel adapters 5 and 6 have the configuration shown in FIG. 6A, and the processor 13 is stored in the control storage 14. Reads and operates the program
Receiving a start I / O command from the channel 1 or 11 via the interface circuit 12;
And the common bus control circuit 1
5 to transfer data to and from other functional units via the common bus 10.

The device adapters 7 and 8 are configured as shown in FIG. 6 (A). The processor 13 reads out the program stored in the control memory 14 and operates. The processor 13 operates via the interface circuit 12 and the adapter 28 or 29. Sends a command to the disk device 3 or 4 to transfer data to and from the disk device 3 or 4, and controls the common bus control circuit 15 to communicate with other functional units via the common bus 10. Perform data transfer.

The resource manager 9 has a configuration as shown in FIG. 6B. A processor 17 operates by reading a program stored in a control memory 16 and controlling a common bus control circuit 18 to control the common bus 10. And receives all start I / O commands from channels 1 and 11
19 and centrally manages the start I / O command, and instructs the channel adapter 5 or 6 and the device adapter 7 or 8 for data transfer processing for each start I / O command.

The control information for every received start I / O command, the control information for each channel path,
And 4 are stored in the RAM 19, and other functional units can access the RAM 19 via the RAM access control circuit 20 and read out the information, thereby centrally managing the information.

For example, if the channel 1 is a channel adapter 5
When the channel adapter 5 sends a start I / O command to the disk device 3 to write data to the disk device 3, the channel adapter 5 requests the resource manager 9 to use the common bus 10,
When permitted, the cylinder address, head address, and record address are stored in the RAM 19 of the resource manager 9.

The device adapter 7 or 8 is operated by the resource manager 9 in accordance with an instruction from the resource manager 9.
When the address stored in the address 19 is read, the disk device 3 is selected via the adapter 28 or 29 according to the address and controlled to position the head at the designated cylinder.

When the seek operation of the disk device 3 is completed and data writing becomes possible, the device adapter 7 or 8 is connected to the channel adapter 5 and the channel adapter 5 is attached to the designated head of the disk device 3. The data to be transmitted is transmitted, and the data is sequentially written from the designated record.

When the channel adapter 5 is instructed to read data from the channel 1, the device adapter 7 or 8 transmits the data read from the designated record by the designated head of the disk drive 3 to the channel 1. Transfer to

The channel 1 accesses the disk device 4 via the channel adapter 5 and the device adapter 7 or 8 and the adapter 28 or 29, and the channel 1
The same applies to the case where the device 1 accesses the disk device 3 or the disk device 4 via the channel adapter 6 and the device adapter 7 or 8 via the adapter 28 or 29, and the detailed description is omitted.

The resource manager 9 of the disk control device 2 sends a patrol servo command to the device adapter 7 or 8 at predetermined time intervals, activates the data surface offset function of the disk devices 3 and 4, and sets the offset of all heads. Instruct the measurement of the amount.

FIG. 7 is a sequence for explaining the operation of the patrol servo. When the issue time of the patrol servo command comes, the resource manager (RM) sets the STA in FIG.
A start operation is issued to the device adapter (DA) as shown in RT PERATION.

Upon receiving the start operation, the device adapter (DA) receives a task control block (T) from the resource manager (RM) as shown in TCB of FIG.
CB) is read, and it is recognized that execution of the patrol servo is instructed by the task code.

Further, as shown in the DCB of FIG.
When the device control block (DCB) is read from the resource manager (RM) to recognize the head position and the like of the disk device (DV), the DEVICE SELECT of FIG.
As shown in CT, a disk device (DV) is selected and FIG.
Patroll servo command is sent to the selected disk device (DV) as shown in CONTROL SERVO.

Next, the device adapter (DA) is shown in FIG.
As shown in RESET INTERRUPT of FIG. 7, an instruction is made that the report by the interruption from the disk device (DV) is unnecessary, and as shown in DCB of FIG. 7, the contents of the device control block stored by the resource manager (RM) are written. Replace. That is, it is recorded that the position of the head of the disk device to be processed is positioned at 0 cylinder.

Then, the DEVICE DISC shown in FIG.
As shown in ONCONNECT, the connection with the disk device (DV) is disconnected.

[0022]

As described above, conventionally, the resource manager 9 sends out patrol servo commands at predetermined time intervals.

However, the device adapter 7 and the adapter 2
8, a switch for disabling the adapters 28 and 29 is provided between the device adapter 8 and the adapter 29. When this switch disables the device, the device adapter is disabled. Even if the device 7 or 8 sends out the DEVICE SELECT to the disk device 3 or 4 as shown in FIG. 7, the disk device 3 or 4 cannot be selected.

Therefore, since the patrol servo command cannot be sent to the disk devices 3 and 4, the disk devices 3 and 4 keep the offset amount collected so far.

After the disable state continues for a long time, the disk device 3 or 4 is accessed from the channel 1 or 11 after the switch is switched to the enable state and before the next patrol servo command is transmitted. When the data is written, the disk devices 3 and 4 correct the head position based on the old offset amount and write the data.

When this old offset amount is used, the old offset amount is often inappropriate due to temperature fluctuations and the like, and data written with the position corrected by the old offset amount is written off the center of the track. It is likely to be caught.

Accordingly, as a result of receiving the next patrol servo command and measuring a new offset amount, the data whose position has been corrected with the old offset amount and written by the head whose position has been corrected with the new offset amount will be described. At the time of reading, there is a problem that data check frequently occurs due to a large displacement of the head.

In view of the above problems, in the present invention, when the patrol servo command is not normally received, the device adapters 7 and 8 write a flag in the DCB, and the device adapter 7 or 8 sends a start I / O command to the device adapter 7 or 8. When came
If a flag exists in the DCB, this start I / O
The purpose is to send a patrol servo command to the disk devices 3 and 4 to execute the command before executing the command.

[0029]

FIG. 1 is a block diagram for explaining the principle of the present invention. The disk control device 22 has a data surface offset function of measuring the offset amount for correcting the deviation amount of the head from the track, and correcting the position with the offset amount, thereby improving the positioning accuracy of the head. It controls the disk device 3 and instructs the disk device 3 to start measuring the offset amount of the data surface offset function at predetermined time intervals.

Then, a flag setting means 24 for setting a flag 23 indicating that an instruction to start the offset amount measurement to the disk device 3 is not normally received, and an input / output instruction to the disk device 3 from the host device 21 are received. When the flag 23 is set at the time of
Before executing the input / output instruction, an instruction issuing means 30 for issuing an instruction for starting the offset amount measurement is provided.

[0031]

With the above configuration, when the flag 23 is set, that is, when the data surface offset function of the disk device 3 does not execute the offset amount measurement at predetermined time intervals, the host device 21 Before executing the input / output command transmitted by the disk controller 22, the disk controller 22 can transmit an offset amount measurement start command, that is, a patrol servo command, to the disk device 3 to execute the offset amount measurement. .

Therefore, data is written after the head displacement is corrected using the latest offset amount, so that occurrence of data check can be prevented.

[0033]

FIG. 2 is a block diagram of a circuit showing an embodiment of the present invention, and FIG. 3 is a sequence for explaining the operation of FIG.

In FIG. 2, the same reference numerals as those in FIG. The device adapters 25 and 26 are shown in FIG.
The program stored in the control storage 14 shown in (A) is different from the device adapters 7 and 8 shown in FIG.

The resource manager 27 is different from the resource manager 27 in that a flag 23 is set in the DCB stored in the RAM 19 shown in FIG. 3 are the same as those in FIG. In FIG. 3, as described above, the device adapter (DA) 25 or 26 is connected to the DEVICE SELECT.
When the disk device (DV) 3 or 4 is selected,
As described above, since the switch disables the adapters 28 and 29, the selection fails, or even if the selection succeeds, the adapter 28 issues a tag (TAG).
Or no response from 29, and CONTROL S in FIG.
When the patrol servo command shown in ERVO cannot be transmitted, as shown in DCB (FLAG ON) in FIG. 3, the device adapter 25 or 26 controls the resource manager (RM) 27 in the common bus control circuit shown in FIG. 1
8, the flag 17 is stored in the RAM 19 for the processor 17.
Request to set 3.

Therefore, the resource manager 27
The flag 23 is written in the DCB stored in the RAM 19 shown in FIG. When the device adapter 25 or 26 is notified by the resource manager 27 of the reception of the start I / O command from the channel 1 or 11 via the channel adapter 5 or 6, the R of the resource manager 27 shown in FIG.
The DCB stored in the RAM 19 via the AM access control circuit 20 is read as shown in the DCB of FIG. 3, and it is checked whether the flag 23 is set. If the flag 23 is set, the start I / O instruction is executed. Before, Figure 3
As shown in PATROL SERVO, a patrol servo command is transmitted.

Then, the device adapter 25 or 26
Is, as shown in the DCB of FIG. 3, after resetting the DCB flag 23, and rewriting the contents of the DCB in the same manner as described above,
As shown in DEVICE DISCONNECT in FIG. 3 (10), the disk device 3 or 4 is once disconnected.

At this time, the device adapter 25 or 26
Does not issue the RESET INTERRUPT shown in FIG. 7 and disconnects from the disk device 3 or 4 in a busy state, thereby causing the disk device 3 or 4 to report the end of the offset amount measurement.

When the end of the offset amount measurement is reported, the resource manager 27 starts again.
An / O command is issued. At this time, since the flag 23 is not set, data write or read processing to or from the disk device 3 or 4 is performed.

FIG. 4 is a flowchart for explaining the operation of FIG. The device adapter 25 or 26
When a start I / O command is received from the resource manager 27 in (1), the resource manager 27 is received in step (2).
, The DCB is read out, and the disk device 3 or 4 is selected in step (3).

Then, in step (4), it is checked whether or not the flag 23 has been set.
The normal processing is executed in (5). If the flag is set in step (4), a patrol servo command is issued in step (6), and the flag 23 is reset in step (7). Then, in step (8), the DCB is rewritten,
In (9), the disk unit 3 or 4 is disconnected in a busy state,
Return to step (1).

[0042]

As described above, according to the present invention, when the data plane offset function of the disk device does not execute the offset amount measurement every predetermined time, the data surface offset function is executed before executing the input / output command sent by the host device. Then, the disk control device can send a patrol servo command to the disk device to execute the measurement of the offset amount.

Therefore, data is written after the head displacement is corrected by the latest offset amount, so that occurrence of data check can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating 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 sequence illustrating the operation of FIG. 2;

FIG. 4 is a flowchart illustrating the operation of FIG. 2;

FIG. 5 is a block diagram illustrating an example of a conventional technique.

FIG. 6 is a detailed block diagram of each functional unit.

FIG. 7 is a sequence illustrating the operation of the patrol servo.

[Explanation of symbols]

 1, 11 channel 2, 22 disk controller 3, 4 disk device 5, 6 channel adapter 7, 8, 25, 26 device adapter 9, 27 resource manager 10 common bus 12 interface circuit 13, 17 processor 14, 16 control storage 15 , 18 Common bus control circuit 19 RAM 20 RAM access control circuit 21 Host device 23 Flag 24 Flag setting means 28, 29 Adapter

Claims (1)

(57) [Claims] 1. A disk having a data plane offset function for improving the positioning accuracy of a head by measuring an offset amount for correcting a deviation amount of a head from a track and correcting a position with the offset amount. apparatus
(3), and instructs the disk device (3) to start measuring the offset amount of the data plane offset function at predetermined time intervals, the disk device (3) comprising: ), A flag setting means (24) for setting a flag (23) indicating that an instruction to start measuring the offset amount is not normally received, and an input / output instruction from the host device (21) to the disk device (3). At the time of reception, if the flag (23) is set, before executing the input / output command, a means (30) for issuing the command for starting the offset amount measurement is provided. Disk control unit.