JPH0329171A - Device and method for controlling disk - Google Patents

Abstract

PURPOSE:To prevent the end of I/O processing in a master device from being delayed by allowing a control device to decide whether a command from the master device is being executed or waiting for execution and executing correcting operation in a state other than the execution waiting state. CONSTITUTION:The control device 2A is provided with a correcting operation request commanding part 21b, a correcting operation detecting part 20c, a correcting operation deciding part 20b, a correcting operation commanding part 20a, a commond processing control part 20d, and a detecting means 20e for detecting the execution or holding of a command. At the time of detecting an off-track correcting operation request, command execution or command holding is decided, and during the period of commond execution or command holding, command processing is continued or executed. In other cases, the off- track correcting operation of the disk device is instructed. Consequently, the generation of a long I/O execution waiting state in the master device 1 can be prevented.

Description

[Detailed description of the invention] [Table of contents] Overview Industrial field of application Prior art (Figure 4) Means for solving the problem to be solved by the invention (Figure 1) Effect (Figure 1) Implementation Example (Fig. 2, Fig. 3) Effect of the invention [Summary] Regarding the disk rtsm device and control method, in order for the host device to perform off-track correction operation of the disk device,
In order to prevent a long period of waiting for human output execution, the control device includes a correction operation request instruction section, a correction operation detection section, a correction operation judgment section, a correction operation instruction section, and a command processing control section. and a detection means for detecting whether a command is being executed or held, and when an off-track correction operation request is detected, the system determines whether the command is being executed or held, and detects whether the command is being executed or held. As a result, if the command is being executed or held, the command processing is continued or executed, and at other times, the off-track correction operation of the disk device is instructed. The system is designed to perform off-track correction operations.

[Industrial application field] The present invention relates to a disk control device and a control method, and more specifically, the present invention is used to control the execution of an off-track correction operation in an external storage device such as a magnetic disk device or an optical disk device. This paper relates to off-track correction operation control that avoids delays in the completion of human output processing in equipment. [Conventional technology]

In recent years, with the improvement in performance and capacity of computer systems, external storage devices (auxiliary storage devices), such as magnetic disk devices and optical disk devices, have expanded in storage capacity, become smaller, and have higher performance. We are being asked to In order to meet these requirements, attempts have been made to improve magnetic disk devices and the like in order to record as large a capacity of data as possible on a small diameter storage medium by increasing the track density on the surface of the storage medium.

However, by increasing the track density, the distance between tracks becomes smaller, which means that the positioning mechanism for positioning the playback/recording head on the track for reading and writing data requires higher precision. I decided to request. On the other hand, it is clear that external storage devices (auxiliary storage devices) in computer systems are always required to have high reliability, and it is necessary to increase capacity by increasing recording density without reducing reliability. ing. Due to its mechanical structure, the head positioning mechanism of magnetic disk drives and the like is easily affected by temperature fluctuations due to the heat generated by the device itself or changes in ambient temperature, which is the biggest cause of deterioration in positioning accuracy. The most effective means to eliminate this drawback is to record physical reference information of the storage medium (generally called servo information) on each storage medium, and to The leveling information is read out at regular time intervals, the relative positional fluctuation between the head and the storage medium is calculated, and the control information for operating the head positioning mechanism is corrected.

The correction operation of the head positioning mechanism works effectively to ensure head positioning accuracy in magnetic disk drives with high track density, but in order to sufficiently absorb temperature fluctuations, it is necessary to correct the head positioning mechanism at certain time intervals. It is necessary to perform a corrective action.

In addition, the correction operation must be performed for each storage medium surface of the device, and since the device generally has more than ten storage medium surfaces,
The correction operation takes a relatively long time.

FIG. 4 is a block diagram of a system using a conventional magnetic disk device. In the figure, l is a host device consisting of a CPU (central processing unit), etc., 2 is a magnetic disk control device, 3 is a magnetic disk device, 4 is an interface connecting the host device wl and the magnetic disk control device 2, and 5 is an interface. This is an interface that connects the magnetic disk control device 2 and the magnetic disk device 3.

In this system, multiple host devices are installed.
An input/output command is issued to one magnetic disk controller 2 via the interface 4.

This magnetic disk control device 2 controls the magnetic disk device 3 via an interface 5 and executes operations specified by commands. In such a system, in a magnetic disk device configured to perform a correction operation of the head positioning mechanism, while the magnetic disk device 3 is performing a correction operation, for example, an off-track correction operation, there is no communication from the host device l. It becomes impossible to execute normal input/output processing (command processing) such as reading and writing issued data. Also, even while input/output processing (command processing) is being executed, off-track correction operations are executed with priority, so input/output processing cannot be executed during that time. For this reason, conventionally, the human output processing received from the host device 1 while the magnetic disk device 3 is performing the off-track correction operation is completed within the magnetic disk control device 2. It was in a waiting state until it was executed. Furthermore, the time period in which the correction operation is required to be performed is unique for each type of magnetic disk drive 3 depending on the characteristics of the mechanical structure of the magnetic disk drive 3. This is done actively at a timing determined by the device itself. For this reason, the host device using the magnetic disk device ends up waiting for execution of the input/output processing for the correction operation.

[Problem to be solved by the invention]

- Conventional works such as the Book of H had the following drawbacks. In other words, in the host device that requested human output processing to the magnetic disk device, if the human output processing overlaps with the execution time of the correction operation, the completion of the human output processing is delayed for a relatively long time. It will look like this. Generally, the period of the correction operation is several minutes or several tens of minutes.
It is considered that the execution delay of human output processing will not have a significant impact on the system performance. In addition, even if the relevant human output processing is waiting for execution in the magnetic disk control device, the input/output processing will be executed immediately after the correction operation in the magnetic disk device is completed, so depending on the system conditions of the host device, In many cases, there is no need to be aware of the occurrence of the execution wait.

However, in systems that cannot tolerate delays in the execution time of individual input/output processes in order to guarantee a constant response time for online terminals, etc., it is necessary to The associated waiting time for execution of input/output processing on the host device becomes a serious problem. SUMMARY OF THE INVENTION An object of the present invention is to eliminate such conventional drawbacks and to prevent a host device from having to wait for a long period of time to perform input/output in order to execute an off-trunk correction operation for a disk device.

[Means to solve the problem]

FIG. 1 is a diagram showing the principle of the present invention, and the principle of the present invention will be explained below based on this diagram.

FIG. 1A is a block diagram of the disk controller. In the figure, l is a host device (multiple units installed), 2 is a control device, 3A is a disk device, 20d is a command processing control unit, 20e is a flag, 21b is a correction operation request instruction unit, and 2a
20b is a correction operation determining section, and 20c is a correction operation detection section. The two controllers include a correction operation instruction section 2a that instructs the disk device 3A to perform off-track correction, and a correction operation judgment section 20b1 that makes a judgment as to whether or not to perform off-track correction. Correction operation detection unit 20 to detect
c. a correction operation request instructing section 21b which instructs the correction operation detection section 20c to perform a correction operation at fixed time intervals, a detection means 20e, which receives commands from the host device i+ and controls the processing thereof; A command processing@control section 20d, etc. is provided to set a flag indicating that the command is being executed or held. When the command processing control unit 20d receives a command from the host device l, it sets a flag (for example, ".0" when there is no command, and ".0" when the command is being held or being executed.
1), the correction operation determination unit 20b can determine whether or not to perform a correction operation by looking at the flag. FIG. 1B is a diagram showing a flowchart of the off-track correction operation @ control method, which will be explained with reference to FIG. 1A. First, the correction operation detection section 20c detects a correction operation instruction from the correction operation request instruction section 21b, and the correction operation determination section 20
Issue an instruction to b (100). The correction operation determination unit 20b determines whether a command from the host device 1 is held or whether the command is being executed based on the flag 20e (1 0 1).

As a result, if a command is being executed or a command is being held, the execution of the command is continued or the held command is executed (103), but if the command is not being executed, If the command is not being held, the correction operation instruction section 2a is instructed to perform a correction operation, and the off-track correction operation is started in the disk device 3A (102).After that, when the above correction operation request is detected again, E-recording is performed. The off-track correction operation is controlled in the same way. [Function] Since the present invention is configured as described above, it has the following functions. @Giso i12A executes the human output command even if the disk device 3A needs an off-track correction operation when it receives the human output command, and when there is no human output command, the disk device executes the correction operation processing. This is to instruct 3A. Therefore, it is possible to perform correction operation processing without having to wait for the execution of human output commands in the host device. [Example] Hereinafter, an example of the present invention will be described based on the drawings. Second
The figure is a block diagram of one embodiment of the present invention, and the same reference numerals as in FIG. 1 indicate the same parts. In the figure, 2 is a magnetic disk control device, 3 is a magnetic disk device, 4 is an interface with a host device, and 5 is an interface with a magnetic disk device. In addition, 20 is the upper interface 'llm section, 20a
20b is a correction operation determining unit, 20c is a correction operation detection unit, and 21 is a lower interface flIl.
21a is a correction operation instruction section, and 21b is a correction operation request instruction section. - h The higher-level interface control unit 20 causes the correction operation instruction unit 20a to determine whether or not the correction operation can be executed fIIIi.
A correction operation determination unit 20b that detects a request for correction operation, a correction operation detection unit 20c that detects a request for correction operation, and an upper interface protocol fil? 1 part (not shown), command processing control part (
(not shown), flag (not shown), etc. The lower interface control unit 21 includes an f-level interface protocol iI1 control unit (not shown) and a correction operation instruction unit 21a that starts a correction operation for the magnetic disk device.
, a correction operation request instruction section 21b, etc. The correction operation request instructing section 21b has a timer of 2 to several tens of minutes, and instructs the correction operation detection section 20c in the upper interface@control section 20 at fixed time intervals. In the upper level interface control unit 20, the E-level interface protocol control unit (not shown) receives commands sent from the higher level device, and the command processing control unit (not shown) receives the commands sent from the higher level device.
(not shown) for processing.

At this time, a flag is set in the command processing control unit to indicate that the command is being executed or held.

Next, an off-track correction operation control method will be described based on the above configuration.

The correction operation request instructing section 21b instructs the correction operation detection section 20c to perform a correction operation at regular time intervals. When the correction operation detection unit 20c detects a correction operation instruction, it keeps the correction operation request state in the register, and
This instructs the correction operation determining section 20b.

The correction operation determination unit 20b determines whether the command from the host device Wl is held or is being executed based on the above flag. As a result, if the command is not being held or being executed, the lower interface aiIl? Correction operation instruction section 21a of section 11 21
The magnetic disk device 3 starts the correction operation by instructing. However, if a command is being executed, it will continue processing the command, and if the command is being held, it will process that command. FIG. 3 is an explanatory diagram of a command execution sequence, and shows a conventional example and an embodiment of the present invention.

(A) is an example of a command execution sequence in a normal state in which the magnetic disk device 3 is not waiting for command execution. - The high level device 1 selects (SEL) L the magnetic disk control device 2 and magnetic disk device 3, and issues a command (CMD
)do. After that, data transfer (DATA) is executed,
The command execution results are reported (STS) from the magnetic disk control device 2 to the host device 1. (B) is an example of a conventional command execution sequence when a command execution wait occurs in the magnetic disk unit W3. In this case, command execution, that is, data transfer (DAT
Until A) is performed, the magnetic disk device will
A wait (WAIT) occurs in order to execute the correction operation of the head positioning mechanism. (C) is an example of a command execution sequence according to the above embodiment of the present invention. In this case, even when the magnetic disk device 3 requires a correction operation, the magnetic disk @ Goso W2 executes the command, and after the execution is completed, if there is no other command waiting for execution,
A correction operation instruction is immediately given to the magnetic disk unit W3, and the correction operation is started. By making this kind of operation sequence possible, the upper
This makes it possible to avoid delays in completing human output processing in l. Note that although the above embodiment describes an example in which a magnetic disk device is used as an external storage device, the present invention is not limited to such a device, and the present invention is applicable to an optical disk device or other devices that require a correction operation. It can be applied to devices that [Effects of the Invention] As explained above, the present invention has the following effects. In the M control device, it is determined whether the command from the host device is being executed or is waiting for execution, and the correction operation is performed when it is not in the state of waiting for execution, so that the human output processing in the host device ends. This makes it possible to avoid delays.

[Brief explanation of drawings]

Fig. 1 is a principle diagram of a disk control device and control method according to the present invention, Fig. 2 is a block diagram of an embodiment of the present invention, Fig. 3 is an explanatory diagram of a command sequence, and Fig. 4 is a block diagram of a conventional example. It is a diagram. 1 Host device 2A--Control device A--External storage device Od--Command processing l1 Control section Oe--Flag lb---Correction operation request instruction section OC-Correction operation detection section Ob-Correction operation judgment section a・One correction operation instruction section

Claims (2)

[Claims] (1) Control the disk device (3A) according to commands from the host device (1), and
A) A disk control device (2A) that performs the off-track correction operation at predetermined time intervals, the control device (2A) comprising a correction operation request instruction unit (2A) that requests the correction operation at predetermined time intervals.
21b), and a correction operation detection unit (20c) that detects the correction operation request.
and a correction operation determination unit (
20b), a correction operation instruction section (2a) that instructs the disk device (3A) to execute a correction operation, and a command processing control section that causes the disk device (3A) to execute a command from the host device (1). (20d), and a detection means (20e) for detecting that the command processing control unit (20d) is executing or holding a command.
), and the correction operation determining section (20b) includes the detecting means (20
A disk control device characterized in that, when e) is detected, it is determined that the correction operation can be executed immediately. (2) A disk control method using the apparatus according to claim 1, wherein when an off-track correction operation request is detected (100), determining whether the command is being executed or the command is being held (
As a result, if the command is being executed or held, command processing is continued or executed (103); if the command is not being executed or held, the off-track correction operation of the disk device is instructed. A disk control method characterized in that the off-track correction operation of the disk device can be performed without waiting for a command from the host device.