JPH04351764A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To promote the reliability of data by parity and to make the write processing time quickened and then to make the device unexpensive. CONSTITUTION:At the time of writing a data to a data storage part 280, an arithmetic circuit 250 and a nonvolatile memory 270 are controlled by a microprocessor 240 and a memory control part 260 controlled by the microprocessor 240, and an exclusive logic sum of a write data from a data transfer control part 220 to the data storage part 280 and a read data from the nonvolatile memory 270 are operated by the arithmetic circuit 250. As a result, a write operation to the nonvolatile memory 270 again is repeatedly performmed on the whole write data, so that parity is stored in the nonvolatile memory 270.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixed data length magnetic disk drive.

0002

[Prior Art] Conventionally, in a system using this type of magnetic disk drive, an error correction code is added after the data in order to improve the reliability of the data, and when a data error occurs, the error correction code is used to correct the data. was corrected and sent to the host system. Recently, in order to further improve data reliability, the dual write method, in which the same data is written to different magnetic disk devices, and the parity disk method, in which the parity magnetic disk device is separate from the data magnetic disk device, have been adopted. has been done.

0003

However, the above-described conventional dual writing system has the disadvantage that the effective disk capacity is only half of the total disk capacity, resulting in high costs. In addition, since the conventional parity disk system also realized the parity disk using a magnetic disk device, there was a drawback that contention occurred on the parity disk even in a cross-call connection, and simultaneous processing could not be performed. Furthermore, in the conventional parity disk method, when writing parity data, the data must be read from the parity disk device, exclusive ORed with the written data, and then written to the parity disk device, which increases the write processing time. The drawback was that it took about twice as long.

0004

[Means for Solving the Problems] A magnetic disk device of the present invention has a magnetic disk processing device interface that exchanges instructions, execution results, and data between a data storage medium that magnetically stores data and a magnetic disk processing device. means, a microprocessor that decodes instructions received through the magnetic disk processing device interface means and sends execution results to the magnetic disk processing device, and transfers data between the data storage medium and the data storage medium according to instructions from the microprocessor. data writing/reading control means for performing;
A magnetic disk device comprising a data transfer control means for controlling data transfer between the magnetic disk processing device interface means and the data write/read control means according to instructions from the microprocessor, a non-volatile storage means; memory control means for controlling read/write and address control of the storage means according to instructions from the microprocessor; and read data from the storage means and data written to the data storage medium from the data transfer control means. and calculation means for performing calculations according to instructions from the microprocessor and writing the calculation results into the storage means.

[0005] The storage means may be a volatile memory with battery backup.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

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

A magnetic disk device 200, which is an embodiment of the present invention, includes a magnetic disk processing device interface unit 210 that exchanges commands, execution results, and data with the magnetic disk processing device 100, and a magnetic disk processing device A microprocessor 240 that decodes instructions received through the interface unit 210 and sends execution results to the magnetic disk processing device 100;
A data write/read control unit 230 exchanges data with the data storage unit 280 according to instructions from the microprocessor 240, and a data write/read control unit 210 and the data write/read control unit 230 according to instructions from the microprocessor 240. A memory control unit 260 that performs memory write/read control and address control according to instructions from the microprocessor 240, and a memory control unit 220 that performs data transfer control between A non-volatile memory 270 reads and writes data based on the control of the microprocessor 260, and the microprocessor 240 reads and writes data from the non-volatile memory 270 and writes data from the data transfer control unit 220 to the data storage unit 280.
The calculation results are stored in the non-volatile memory 2.
It is configured by adding an arithmetic circuit 250 for writing data to 70.

Next, regarding the operation of this embodiment, the block diagram of the arithmetic circuit 250 and nonvolatile memory 270 shown in FIG. 2, and the arithmetic circuit 250 and nonvolatile memory 2 shown in FIG.
This will be explained with reference to the timing chart of No. 70 and the arrangement of data and parity in the data storage section 280 and nonvolatile memory 270 shown in FIG. In this embodiment, the parity Pj (j is an integer from 0 to n, n+1 = number of sectors) is the data dij (i is the head number, j is the sector number) of the same byte in the same sector of each head in the same cylinder. It is assumed that the exclusive OR is taken. However, depending on the memory capacity, it is also possible to change the combination of data to perform the exclusive OR.

First, the operation at the time of initial setting of this embodiment will be explained.

Magnetic disk processing device interface section 2
10, microprocessor 240 receives initialization instructions. In the microprocessor 240, after validating the initialization enable signal 1 (see FIG. 2) for the arithmetic circuit 250 according to this initial setting instruction, the memory control unit 2
60 to initialize the nonvolatile memory 270 (instruction to write all 0 data to all addresses). Around this time, formatting of the storage medium of the data storage unit 280 (writing all 0 data to the entire data area) is carried out, so the entire data area is

0012

It can be seen that the following holds true.

Next, the operation when writing to the data storage section 280 will be explained.

After the microprocessor 240 disables the initialization enable signal 1 to the arithmetic circuit 250 when the above-mentioned initialization is completed, when a data write command is sent from the magnetic disk processing device 100,
The memory control unit 260 is instructed to store the exclusive OR result of the data 2 written to the data storage unit 280 by the arithmetic circuit 250 and the memory data 5 read from the nonvolatile memory 270 in the nonvolatile memory 270 again. give instructions. As shown in FIG. 3, in the memory control unit 260, after enabling the chip enable signal 7 for the non-volatile memory 270, it sends an address and changes the write enable signal 6 from enable to disable, and then sends the address to the data storage unit 280. When these operations for all write data are completed, the chip enable signal 7 is invalidated. It can be easily understood that the above-mentioned operation holds the above-mentioned formula (1).

When reading data from the data storage unit 280, equation (1) is always held, so reading can be performed in the same manner as in conventional magnetic disk drives. When an uncorrectable read error occurs, it is assumed that an uncorrectable read error has occurred in data dkl, and all data dil except data dkl are sequentially read into the nonvolatile memory 270,

[0017]

After sequentially calculating dkl, the obtained dkl is written into the data storage section 280, and the process is terminated.

Note that the nonvolatile memory 2 in this embodiment
The same effect can be obtained by using a nonvolatile memory with battery backup instead of 70.

[0020]

As explained above, the present invention provides a conventional magnetic disk drive with a non-volatile storage means, a memory control means for controlling read/write and address control of the storage means, and a storage means. By adding a calculation means for performing calculations on the output and the data written to the magnetic storage medium, it is possible to provide a magnetic disk device with excellent reliability and processing performance at a low cost.

[Brief explanation of the drawing]

FIG. 1: A magnetic disk device 20 which is an embodiment of the present invention.
0 is a block diagram of 0.

FIG. 2 is a block diagram of an arithmetic circuit 250 and a nonvolatile memory 270 in FIG. 1.

FIG. 3 is a timing chart of the portion shown in FIG. 2;

4 is a diagram for explaining the arrangement of data and parity in the data storage unit 280 and nonvolatile memory 270 of FIG. 1. FIG.

[Explanation of symbols]

100 Magnetic disk processing device 200 Magnetic disk device 210 Magnetic disk processing device interface section 220 Data transfer control section 230 Data write/read control section 240 Microprocessor 250 Arithmetic circuit 260 Memory control section 270 Non-volatile memory 280 Data storage section 251 ANDOR circuit 252 Exclusive OR circuit.

Claims (2)

[Claims] 1. A magnetic disk processing device interface means for exchanging commands, execution results, and data between a data storage medium that magnetically stores data and a magnetic disk processing device, and a magnetic disk processing device interface means for receiving instructions, execution results, and data through the magnetic disk processing device interface means. a microprocessor that decodes the commands and sends execution results to the magnetic disk processing device; a data write/read control unit that transfers data to and from the data storage medium according to instructions from the microprocessor; A magnetic disk device comprising a data transfer control means for controlling data transfer between the magnetic disk processing device interface means and the data write/read control means according to instructions from a processor, a non-volatile storage means; memory control means for controlling read/write and address control of the storage means according to instructions from a processor; A magnetic disk device characterized by comprising: arithmetic means for performing arithmetic operations according to instructions from a processor and writing the arithmetic results to the storage means. 2. The magnetic disk device according to claim 1, wherein the storage means is a volatile memory with battery backup.