JPH0242688A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To surely capture and detect an error by providing a CRC checking function to input a CRC code for detecting an error and to execute the error detection of write data and a CRC preparing function to prepare the CRC code for detecting an error and to feed it to a host device along with read data. CONSTITUTION:The title device is equipped with a control means having function to write prescribed data according to the write command of the write data from the host device, simultaneously, to read the prescribed data according to a read command from the high order device and to feed them at the host device. To the control means, a CRC cycle redundancy checking circuit 1 is parallely provided. The title device is equipped with the CRC checking function to input the CRC code for detecting the error along with the data and to execute the error detection of the write data at the time of inputting the write data from the host device and the CRC preparing function to prepare the CRC code for detecting the error from the read data and to feed it to the host device along with the read data at the time of reading the data sent to the host device. Thus, even when the error of an even bit is generated to the write data or read data, it can be effectively detected.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to this type of magnetic disk device, and particularly,
The present invention relates to a magnetic disk device equipped with an error correction code circuit.

[Conventional technology]

Conventionally, in this type of magnetic disk device, when writing data from a host device, the sent write data is written as is, and when the write data is completed, errors generated from the subsequent write data are written. A correction code is written. On the other hand, when reading written data, the read data is sent as is to the host device, and after the written data has been sent, the error correction code written at the time of writing is subsequently read out. Based on this error correction code, it is determined whether the data sent to the host device is correct. Here, write data from the host device and read data to the host device are handled in byte or word units, and error detection is performed by adding a parity bit for error detection between the host device and the magnetic disk device. A method has been adopted to do this.

[Problem to be solved by the invention]

In the above conventional example, as described above, an error detection parity bit is added as a redundant bit to the write data from the host device and the read data to the host device. Furthermore, in the conventional example described above, there is a problem in that when an even-numbered bit error occurs in the write data or successive data, the write data and the read data are considered normal.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic disk device that can improve the disadvantages of the conventional example and, in particular, can effectively detect even-numbered bit errors even if they occur in write data or read data. be.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described based on FIGS. 1 to 3. The embodiment shown in FIG. 1 is a control means that has the function of writing predetermined data in accordance with a write data write command from a host machine, and reading out predetermined data in accordance with a read command from a host machine and sending it out by the host machine. (not shown).

This control means includes a CRC circuit (CRC is Cycl
IC Redundancy Check (abbreviation for cyclic redundancy check) 1 is also installed.

This CRC circuit 1 has a CRC check function that inputs a CRC code for error detection together with the data when manually writing data from the host machine to detect errors in the write data, and when reading data to be sent to the host machine. ,
It has a CRC generation function that generates a CRC code for error detection from the read data and sends it to the host machine together with the read data.

To explain this in more detail, when writing data, the CRC circuit 1 inputs the write data on the data bus 4 and a CRC code for error detection following the write data, and performs error detection. Write data K to.

Output.

ECC (However, Error Correcting
Code: Abbreviation for error correction code) The circuit 2 has the function of inputting the write data on the data bus 5, generating an ECC code, and outputting the ECC code as the write data to the data bus 6. . To write data, and EC
The C code is input to the parallel-to-serial conversion circuit 3 and becomes serial data, which is output to the serial data line 7 and written. FIG. 2 shows each data bus 4, 5 in this case.
The contents of ゜6 are shown below.

When reading data, the read data Y1 and ECC code are sent from the serial data line 7 to the parallel-serial converter circuit 3.
The data is input manually and output to the data bus 6 as parallel data.

The ECC circuit 2 inputs a continuation ECC code to the read data and successive data on the data bus 6 to perform error detection, and outputs the read data to the data bus 5. On the other hand, C
The RC circuit 1 inputs the read data of the data bus 5, and
It generates an RC code, outputs the read data and the CRC code for the read data to the data bus 4, and sends it to the host device.

FIG. 3 shows the contents of each data bus 6.5.4 in this case.

〔Effect of the invention〕

As described above, according to the present invention, even if not only even bit errors but also other errors occur when transmitting and receiving data with a host device, the CRC circuit can reliably capture and detect these errors. This makes it possible to provide an unprecedentedly superior magnetic disk device that can perform the following functions.

[Brief explanation of the drawing]

Claims (1)

[Claims] (1) A magnetic disk having a control means that writes predetermined data in accordance with a write data write command from a host machine, and reads out predetermined data in accordance with a read command from a host machine and sends it to the host machine. In the apparatus, a CRC circuit is provided in addition to the control means, and the CRC circuit is
The RC circuit has a CRC check function to detect errors in the written data by inputting a CRC code for error detection along with the data when inputting write data from the host machine, and reads data sent to the host machine. A magnetic disk device characterized in that it is sometimes equipped with a CRC generation function that generates a CRC code for error detection from the read data and sends it to a host machine together with the read data.