JPH05150909A - Magnetic disk device with data compare mode - Google Patents

Abstract

PURPOSE:To improve the reliability of read/write data without an influence upon higher-order devices by providing a magnetic disk device with two magnetic disk heads independent of each other. CONSTITUTION:Data are read and written by first and second data read/write means 8 and 9, and data obtained by them are compared with each other by a data comparing means 7. When they coincide with each other because they are correct, data is sent to a data transfer means 6 through a data line 202. The data transfer means 6 transmits read data to a higher-order device 20 through a data line 201, an interface part 1, and a data line 200 and reports it to a command control means 3 through a control line 121 that the command of the read system is correctly completed. If data comparison is omitted, the command control means 3 selects the data read/write means 8 or 9 capable of quicker access in accordance with a cylinder to be accessed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information processing device,
In particular, it relates to a magnetic disk device.

[0002]

2. Description of the Related Art Conventionally, a magnetic disk device receives a command from a higher-level device, seeks to a designated position (cylinder, track, sector) and performs a read / write operation. Whether or not the received data was really correct was that the command for the higher-level device had to be issued again to the same position.

[0003]

In recent years, magnetic disk devices have come to be able to hold a large amount of data with an increase in capacity. For this reason, important data is increasing, and in order to improve the reliability of reading the data recorded in the magnetic disk device and the reliability of writing the data, the software of the host device is used. The drawback is that you have to be aware of it, and you have to modify the software in the past.

An object of the present invention is to provide a magnetic disk device with a data compare mode, which has improved reliability without affecting the host device.

[0005]

In order to achieve the above object, in a magnetic disk device with a data compare mode according to the present invention, an interface unit for exchanging data, commands and the like with an upper device, and an upper device A command interpreting means for interpreting a command received from the device, a command control means for issuing an instruction to each part by the received command to execute the command, a magnetic disk head control mechanism for controlling the position of the first magnetic disk head, and a second
A magnetic disk head control mechanism for controlling the position of the magnetic disk head, a data transfer means for exchanging read / write data with a higher-level device, a data comparison means for comparing two types of data, It includes first data read / write means for reading and writing data from the magnetic disk head, and second data read / write means for reading and writing data from the second magnetic disk head.

[0006]

The reliability is improved by providing the magnetic disk device with two sets of independent magnetic disk heads.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram according to an embodiment of the present invention.

In FIG. 1, this embodiment is a device 2 on the upper side.
0, an interface unit 1 for exchanging data, commands, etc., a command interpreting unit 2 for interpreting a command received from a host device, and a command control unit 3 for issuing an instruction to each unit by the received command and executing the command.
A first magnetic disk head control mechanism 4 for controlling the position of the first magnetic disk head, a second magnetic disk head control mechanism 5 for controlling the position of the second magnetic disk head, and reading and writing. Data transfer means 6 for exchanging data to be transferred to a higher-level device, data comparison means 7 for comparing two types of data, and first data read / write for reading and writing data from the first magnetic disk head. It has means 8 and second data read / write means 9 for reading and writing data from the second magnetic disk head.

The magnetic disk device 10 with a data compare mode has a mode for reading / writing data similar to other magnetic disk devices (hereinafter referred to as a normal access mode), and particularly improves reliability of data reading / writing. It has a data compare mode used when it is desired to make it, and these modes are determined by the device on the upper side.

First, the operation in the data compare mode will be described.

When the magnetic disk device 10 with the data compare mode receives the command issued from the upper device 20 through the disk control line 100, the command interpreting means 2 through the interface unit 1 and the control line 110.
Take in.

The command interpreting means 2 interprets the received command and judges whether it is a seek command or a read / write command accompanied by data transfer.
If the command is a seek command, the command interpreting means 2 notifies the command control means 3 through the control line 111 that the command for moving the magnetic disk head to the target cylinder number has been issued.

The command control means 3 includes control lines 122 and 1
Through 23, the first magnetic disk head control mechanism 4 and the second magnetic disk head control mechanism 5 are instructed to move the magnetic disk head to the target cylinder.

The first magnetic disk head control mechanism 4 and the second magnetic disk head control mechanism 5 move the magnetic disk head to a designated cylinder and notify the completion of the operation through the control lines 122 and 123 to the command control means 3 Let us know.

The command control means 3 confirms that both of the magnetic disk heads have moved to the target cylinders and confirms that the seek command has been completed.
Let me know. In the case of a read type command, the command interpreting means 2 notifies the command control means 3 through the control line 111 that the command for reading data has been issued.

The command control means 3 informs the data transfer means 6 through the control line 120 that the data will be read from now on, and also compares the two types of data read at the time of reading the data via the control line 121. The data comparison means 7 is instructed to do so.

When the data transfer means 6 and the data comparison means 7 are ready, the data is read out to the first data read / write means 8 and the second data read / write means 9 through the control lines 124 and 125. Give instructions.

The read data is stored in the data line 203,
The data is compared by the data comparison means 7 through 204. If the compared data match correctly, the data is sent to the data transfer means 6 through the data line 202, and the data transfer means 6 reads the data to the upper device 20 through the data line 201, the interface section 1 and the data line 200. And the command control means 3 through the control line 121 that the read system command has been correctly completed.

If the compared data do not match correctly, the command control means 3 is notified through the control line 121 and the data is read again. If correct data cannot be obtained even after retrying, it is reported to the higher-level device 20 that the device is abnormal.

In the case of a write type command, the command interpreting means 2 notifies the command controlling means 3 through the control line 111 that the command for writing data has been issued.

The command control means 3 informs the data transfer means 6 through the control line 120 that data is about to be written, and when writing data through the control line 121, the data to be written and the actual writing. The data comparison means 7 is instructed to compare the two types of data.

When the data transfer means 6 and the data comparison means 7 are ready, data is written to the first data read / write means 8 and the second data read / write means 9 through the control lines 124 and 125. Instruct to read the written data.

Data is written by the magnetic disk head closer to the sector to write the data, and the written data is read by the other magnetic disk head. The data to be written is the data line 2 through the data line 200, the interface section 1, the data line 201, the data transfer means 6, the data line 202, and the data comparison means 7.
03 or 204, the first data read / write means 8 or the second data read / write means 9.

The read data is taken into the data comparing means 7 through the data line 203 or 204 and compared. When the compared data match correctly, the command control means 3 is notified through the control line 121 that the write command has been correctly completed. If the compared data do not match correctly, the command control means 3 is notified through the control line 121 and the data is written again. If correct data is not written even after retrying, it is reported to the host device as a device error.

As described above, in the data compare mode,
The read data and the write data are compared on the magnetic disk device side and do not affect the program on the host device side.

Next, the normal access mode will be described. In the normal access mode, in order to shorten the access time, the cylinder is divided into the outer half and the first data read / write unit 8 and the second data read / write unit 9 share the cylinders.

When the magnetic disk device 10 with the data compare mode receives a command issued from the upper device 20 through the disk control line 100, the command interpreting means 2 through the interface unit 1 and the control line 110.
Take in.

The command interpreting means 2 interprets the received command and judges whether it is a seek type command or a read type / write type command accompanied by data transfer.
If the command is a seek command, the command interpreting means 2 notifies the command control means 3 through the control line 111 that the command for moving the magnetic disk head to the target cylinder number has been issued.

The command control means 3 judges whether the target cylinder is in the outer peripheral half or the inner peripheral half, and when it is in the outer peripheral half, the command control means 3 sends the control signal to the first magnetic disk head control mechanism 4 through the control line 122. When it is in the half circumference, it instructs the second magnetic disk head control mechanism 5 through the control line 123 to move the magnetic disk head.

The first magnetic disk head control mechanism 4 and the second magnetic disk head control mechanism 5 move the magnetic disk head to a designated cylinder and indicate that the operation is completed through the control lines 122 and 123. Let me know.

The command control means 3 confirms that the magnetic disk head has moved to the target cylinder and informs the higher-level device 20 that the seek command has been completed. In the case of a read / write type command, the command interpreting means 2 informs the command control means 3 through the control line 111 that a command for reading / writing data has been issued.

The command control means 3 informs the data transfer means 6 and the data comparison means 7 that data will be read / written from now on through the control line 120.
When the data transfer means 6 and the data comparison means 7 are ready, if the target cylinder is on the outer circumference, the control line 12
To the first data read / write means 8 through 5,
When it is in the inner circumference, the second data read / write means 9 is instructed to read / write data through the control line 124.

The read data and the written data are the data line 200, the interface section 1 and the data line 2, respectively.
01, the data transfer means 6, the data line 202, the data comparison means 7, and the data line 203 or 204, the upper device 20 and the first data read / write means 8 or the second.
It is exchanged with the data read / write means 9. When the data transfer is completed, the data transfer means 6 notifies the command control means 3 through the control line 120.

By thus performing the access by dividing the cylinder into the outer peripheral portion and the inner peripheral portion, there is an effect that the moving time of the magnetic disk head is half that of the conventional magnetic disk device.

[0035]

As described above, according to the present invention, by providing the magnetic disk device with two sets of independent magnetic disk heads, the reliability of read / write data can be improved by the magnetic disk device itself. Can be improved without being aware of it.

In addition to the case where the performance is emphasized in addition to the reliability improving mode, the time until the two sets of magnetic disk heads share the outer half and the inner half of the cylinder and move to the target cylinder. Can be shortened, and access performance comparable to or better than that of a conventional magnetic disk can be obtained.

In any case, it is possible to deal with the above by simply designating the mode of the magnetic disk device without considering the reliability and performance in the upper device, and facilitating the inheritance of conventional assets. You can

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Interface section 2 Command interpreting means 3 Command control means 4 First magnetic disk head control mechanism 5 Second magnetic disk head control mechanism 6 Data transfer means 7 Data comparison means 8 First data read / write means 9 Second Data read / write means 10 Magnetic disk device with data compare mode 20 Upper device 100 Disk control line 110 Control line 111 Control line 120 Control line 121 Control line 122 Control line 123 Control line 124 Control line 125 Control line 200 Data line 201 data Line 202 Data line 203 Data line 204 Data line

Claims (1)

[Claims] 1. An interface unit for exchanging data, commands and the like with an upper apparatus, command interpreting means for interpreting a command received from an upper apparatus, and issuing an instruction to each unit by the received command to execute a command. Command control means, a magnetic disk head control mechanism for controlling the position of the first magnetic disk head, a magnetic disk head control mechanism for controlling the position of the second magnetic disk head, and data for reading and writing on the upper side. Data transfer means for exchanging data with the device, data comparison means for comparing two types of data, first data read / write means for reading and writing data from the first magnetic disk head, and second magnetic The second data that reads and writes data from the disk head Magnetic disk unit-integrated data compare mode, characterized in that it comprises a look out / write means.