JPH0424823A - Magnetic disk device and its control system - Google Patents

Abstract

PURPOSE:To prevent the erasion of data caused by the cut-off of a power supply, etc., by writing the data stored in the data buffer backed up by a power supply different from that of a disk device and having the capacity equivalent to one sector or more onto the disk surface in a state separated from a host system device. CONSTITUTION:A data buffer 120 is backed up by a power supply 130 different from that of a disk device 1 and the data stored in the buffer 120 are stored as they are even if the power supply of the device 1 is cut off. Then the data are written onto the disk surface from the buffer 120 after the data equivalent to one sector or more are transferred to the buffer 120 from a host system device. As a result, the data written onto the disk surface are always secured for each sector. Furthermore a flag register 108 is also backed up like the buffer 120 and consists of a flag showing the executing mode of a write command and a flag showing that the data stored in the buffer 120 are valid by an amount equivalent to one sector or more. Thus the data destroyed by the interruption of the writing action can be recovered and the reliability of the disk is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to disk devices such as magnetic disk devices and floppy disk devices, and particularly to a control method suitable for improving the reliability of disk devices.

[Conventional technology]

As described in Japanese Unexamined Patent Publication No. 157629/1980, conventional devices are equipped with a protection circuit to prevent the write permission signal (WG) from becoming invalid during the write process, thereby preventing incomplete recording of data. Ta.

[Problem to be solved by the invention]

The above-mentioned conventional technology does not take into consideration the possibility that the drive motor that rotates the disk will stop due to power cutoff, and if the motor stops, there is a problem that the data being written will be lost.

An object of the present invention is to prevent data from being lost due to a power cut, etc., and to improve the reliability of a disk device.

[Means to solve the problem]

In order to achieve the above purpose, a data buffer with a capacity of one sector or more that is backed up by a power supply separate from the power supply of the device and a flag register that stores the operating state of the device when the device power is turned off are installed in the magnetic disk device. A function is added to write the data in the data buffer onto the disk surface in a state separated from the host system device.

When the magnetic disk device is powered on, the flag register is referred to, and if the magnetic disk device was in a writing operation when the power was last turned off, the data in the data buffer is written to the disk surface to prevent data destruction or loss. prevent,
This improves the reliability of the disk device.

[Effect]

Data transferred from the host system to the disk device is written onto the disk surface via a data buffer.

The data buffer is backed up by a power source separate from the device power supply, and the data therein is retained even when the device power is turned off.

Writing from the data buffer to the disk surface is performed after one sector or more of data has been transferred from the host system to the data buffer, so that the data being written to the disk surface is always secured in sector units.

The flag register is also backed up like the data buffer, and consists of a flag indicating that a write command is being executed and a flag indicating that the data in the data buffer is valid for one sector or more.

As an initial operation when the disk device is powered on, it refers to the flag register and writes the data in the data buffer to the disk surface if the operation when the device was previously powered off was write and the data in the buffer is valid.

By doing this, data corruption caused by write interruption can be recovered and the reliability of the disk can be improved.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an example of the configuration of a disk device using the present invention.

The data buffer 120 shown in the figure is backed up by a storage battery 130, and its contents are saved even if the power to the disk device 1 is turned off.

When a higher-level system device requests activation of the disk device 1 via the disk interface bus a, the microprocessor 101 detects the activation request from the higher-level system device based on an interrupt signal from the interface control circuit 104. When a startup request is detected, microprocessor 1
01 is command code 2 of command parameter 2 set in the register in the interface control circuit.
Decipher 01. If the command is a write process, the microprocessor 101 executes the write process as follows according to the flow shown in FIG.

The microprocessor 101 first sets the write busy bit (
(hereinafter referred to as WBB). Next, the processing start address 202 of the command parameter 2 is transferred to the data buffer 12.
0 address register 109. Next, clear the data complete bit (hereinafter referred to as DCB) of the flag register 108, which indicates that the sector data buffer 110 is valid. The data buffer control circuit 105 and the one-interface control circuit 104 transfer data from the upper system device to the sector data buffer 110. When one sector worth of data is transferred to the sector data buffer 110, the DCB is set and the data in the sector data buffer 110 is transferred to the disk 1 by the read/write control circuit 106 and the serial/parallel conversion circuit 107.
Write on the board surface of 03.

When the data in the sector data buffer 110 has been written to the disk surface, the DCB is cleared.

When the processing for the number of sectors specified by the command parameter is completed, the WBB is cleared and the interface control circuit reports the completion of the processing to the higher-level system device. If there are still unprocessed sectors, the address register is The contents are incremented and the above-mentioned process starting from transfer from the host system device to the sector data buffer 110 is repeated.

FIG. 4 shows the processing flow when the power is turned on.

When the power of the disk device 1 is turned on, the microprocessor 101 writes WBE and DCB of the flag register 108.
If both bits are set, disk 103 is selected.
It is determined that the power is turned off while data is being written to the disk surface, and the data held in the sector data buffer is written to the address on the disk 103 indicated by the address register 109. When the writing is completed, the WBB and DCB are cleared and the host system unit is notified that the disk device is ready.

Note that the storage battery 103 is charged while the disk device 1 is powered on.

〔Effect of the invention〕

According to the present invention, even if the write process of the disk device is interrupted due to an inappropriate power off of the system unit or a system failure, the write process is performed again when the power is turned on, so that bad sectors caused by the write process interruption can be recovered and the disk drive is Improved reliability.

Furthermore, since the buffer for holding data and the data buffer can be used in common, it is possible to prevent an increase in hardware.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a disk device using the present invention, FIG. 2 is a diagram showing command parameters to the disk device,
FIG. 3 is a flow diagram of a disk write process, and FIG. 4 is a flow diagram of a disk process when the power is turned on. 1... Disk device, 101... Microprocessor. 102... Control data RAM, 103... Disk, 104... Interface control circuit, 105...
Data buffer control circuit, 106... Read/write control circuit, 107... Serial/parallel conversion circuit,
108...Flag register. 109...Address register, 110...Sector data buffer, 120...Data buffer, 130...Storage battery. a...Disk interface bus, b...Microprocessor bus, 2...Command parameters, 201...Command code, 202...Processing start address, 203...Number of sectors to be processed. Horizontal drawing θ Drawing command parameter Bulk drawing + Figure

Claims (1)

[Claims] 1. A memory that is backed up by a power supply separate from the power supply of the main unit in the disk device and whose contents can be retained even when the power of the main body is turned off, and a memory that stores the operating state of the device when the power of the device is turned off. The storage mechanism is separated from the host device,
A magnetic disk device characterized by having a command or operation mode for writing from a data buffer to a disk surface. 2. In a computer system using a magnetic disk according to claim 1, when the power is turned on, the operating state of the disk when the power was last turned off is checked, and if the power was turned off during a write operation, it is stored in the data buffer. A magnetic disk control method characterized by writing the generated data onto the disk surface.