JPH0464978A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To prevent erroneous correction in the case of error of an error correction code by adding a parity bit to write data and the error correction code to write them on a magnetic medium and detecting whether the parity is correct or not at the time of reading them. CONSTITUTION:It is detected by a parity detecting/generating circuit 11 whether the parity of 9-bit data is correct or not. The error correction code calculated by an error code generating circuit 9 is converted from parallel data to serial data by a data modulating circuit 6, and the write mode is set to write this data on a magnetic medium 1 by one designated magnetic head. Next, data is read out by one designated magnetic head and is amplified and is converted to a digital signal and is converted from serial data to parallel data. It is detected by a parity detecting circuit 21 whether the parity is correct or not, and the result is reported to a higher-order device. At this time, it is finally detected by the circuit 11 whether the parity is correct or not to confirm whether data is changed in a magnetic disk device or not.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk device that sends and receives data of one or more bytes including parity in units of bytes to and from a binary device.

[Prior art] A conventional magnetic disk device that sends and receives data of 1 byte or more with parity of the 1st to 119th positions of each pie is as shown in FIG. It has a unique structure.

That is, the data of 9 hits (8 bits 1 to -> - parity) is sent from the host device via the command/data line 12 to the human output control unit 26 and the parity detection/generation circuit 27 to detect whether the parity is correct or incorrect. The 8-bit data excluding parity is transferred to the 8-bit data line 25.
The data is sent from the input/output control unit 26 to the data buffer 24 via the input/output controller 26, where it is temporarily stored. This data is further processed by an error code generation circuit 2 in order to write it on the magnetic medium 1.
3, where it is converted from parallel data to serial data by the data modulation circuit 22 together with the error correction code multiplied by 1\1, and is also converted into a format to be written on the magnetic medium 1, and sent to the switching circuit via the writing circuit 5. Sent to 4. The switching circuit 4 is set to the write mode by the write/'read switching signal 3, and the one magnetic head specified by the head switching signal 14 from among the plurality of magnetic spatulas 1 to 2 is set to the corresponding magnetic medium 1. Write data.

Reading of data written on the magnetic medium 1 is performed by writing, /
In the switching circuit 4 set to write mode by the read switching signal 3, one magnetic spatula l~ specified from the plurality of magnetic heads 2 is selected by the head switching signal 14, and data is read out. The signal is amplified by readout circuit 15 and sent to peak detection/pulsing circuit 16 . The peak detection/pulsing circuit 16 converts the input analog signal into a digital signal and sends it to the data demodulation circuit 28.
The data demodulation circuit 28 demodulates the data and converts it from serial data to parallel data.

This converted data is sent to an error detection/correction circuit 12 for error detection and correction. When an error is detected in the error detection/correction circuit 12, the error signal 20 is reported to the host device via the human output control section 26, indicating that the data is incorrect. When no error is detected, the data is sent to the data buffer 24 via the data lines 1 to 2 and temporarily stored therein.

This data is further sent to the host device via the 8-bit data line 25 and the command/data line 12. At this time, parity is added by the parity detection/generation circuit 27. In such data write/read operations, only data to which no parity is added is recorded and reproduced on the magnetic medium 1.

[Problem to be solved by the invention]

Conventional magnetic disk drives such as those described above do not use the parity of data sent from a host device in write/continue operations within the magnetic disk drive, and monitor changes from the data input point to the output point. Moreover, since parity is not added to the error correction code, if there is an error in the error correction code, it will be incorrectly corrected, resulting in a lack of data accuracy. .

[Means to solve the problem]

The magnetic disk device of the present invention has a command/data line of 1 byte or more including parity for each byte for sending and receiving data to and from a host device, and a command/data line that is sent via the command/data line. a parity detection/generation circuit that detects whether the parity of the data is correct and generates the parity;
an input/output control unit that controls transmission and reception of data with the host device; a data buffer that temporarily stores data to absorb a difference in transfer speed between the host device and the magnetic disk device; an error code generation circuit that generates an error correction code for detecting and correcting errors in write data; a parity generation circuit that generates parity of the error correction code generated by the error code generation circuit; a data modulation circuit that converts the error correction code into a format that is written to a recording medium including its parity; a data demodulation circuit that demodulates the signal read from the recording medium and subjected to one pulse; and the data demodulation circuit. A parity detection circuit detects whether the parity of the demodulated data is correct, an error detection/correction circuit detects and corrects errors in the demodulated data, and the data from the error detection/correction circuit is stored in the 1F memory. It is equipped with a read data line for sending data to the data center.

〔Example] Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a ten-step diagram showing one embodiment of the present invention.

In Figure 1, 9 bits (8 bits + parity) of data are transmitted from the host device to the command/'data line 12.
The signal is inputted to the input/output control unit 13 and the parity detection/generation circuit 1-1 via the input/output controller 13, and the correctness or incorrectness of the parity is detected.

The data that has entered the input/output control unit 13 is sent to the data buffer 0 together with parity and is temporarily stored there. This data is further sent to an error code generation circuit 9 for writing onto the magnetic medium 1. , the error correction code calculated there is the parity generation time li! 88 along with parity bits 1 to 7 of the error correction code.
The data is sent to the digital modulation circuit 6, where it is converted from parallel data to serial data and converted into a format to be written on the magnetic medium 1, and sent to the switching circuit 4 via the write circuit 5. The switching circuit 4 is set to a write mode by the write/read switching signal 3, and writes the data to the corresponding magnetic medium 1 by one magnetic head from among the plurality of magnetic heads 2 designated by the head switching signal 14. It's crowded.

Reading of data written on the magnetic medium 1 is performed by selecting one of the magnetic heads 2 designated from among the plurality of magnetic heads 2 by the head switching signal ]4 in the switching circuit 4C set to write mode by the write/read switching signal 3. - Select the magnetic heads to read data, and read out the read signal from the read circuit 1.
5 and amplifies it and sends it to the peak detection/pulsing circuit 16. The peak detection/pulsing circuit 16 converts the input analog signal into a digital signal and sends it to the data demodulation circuit 17, which demodulates this and converts it from serial data to parallel data.

The parity detection circuit 21 detects whether the parity of the converted data is correct or incorrect. The demodulated data also undergoes error detection/correction to detect and correct errors.
It is sent to one correction circuit. If an error is detected in one of the error detection/correction circuits, the fact that the read data is incorrect is reported to the first device via the input/output control section 1-3 by means of an error signal 20. If no error is detected, it is sent along with the parity hit to the data server 10 via the read data line 18 and temporarily stored. This data is further stored in the input/output control unit 1.
3 to the host device via the command/data lines 1-2. At this time, the parity detection/generation circuit 1
), the parity is finally detected as correct or incorrect.
It is confirmed whether or not there has been a change in data within the magnetic disk device.

〔Effect of the invention〕

As explained above, the magnetic disk drive of the present invention adds parity pits to the write data and error correction code and writes them to a magnetic medium, and when reading the data, detects whether the parity is correct or not, thereby adding the parity bits to the error correction code. This has the effect of preventing erroneous correction when an error occurs in the data, thereby ensuring the accuracy of the data.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing an example of a conventional magnetic disk device. 1...-Magnetic medium, 2...-Magnetic spatula I,
3...Write/continue output switching signal, 4...
・Switching circuit, 5...Writing circuit, 6.22...
...Data modulation circuit, 7...Parity pit, 8...Parity generation circuit, 9.23...
...Error code generation circuit, 1.0-24-...T-
Tahafa, 11/27...Parity detection/generation circuit, 12...Command 1/data line, 13/26
--- Input/output control unit, 14... Head switching signal, 1-5... Readout circuit, 16... Peak detection/pulsing circuit, 17-28...・・Data demodulation circuit, 18・29−・・Read data line, 1
1...Error detection/correction circuit, 20...Error signal, 21...Parity detection circuit, 25--8 bit data line.

Claims (1)

[Claims] 1. A command/data line of one or more bytes including parity in each byte for transmitting and receiving data to and from a host device, and the data sent via the command/data line. a parity detection/generation circuit that detects and generates parity correctness; an input/output control unit that controls data transmission and reception between the host device; and a transfer rate between the host device and the magnetic disk device. a data buffer that temporarily stores data to absorb the difference in data; an error code generation circuit that generates an error correction code for detecting and correcting errors in written data; and an error correction code generated by the error code generation circuit. a parity generation circuit that generates parity of the data; a data modulation circuit that converts the write data and the error correction code into a format that includes their parity and is written to a recording medium; a data demodulation circuit that demodulates the signal;
a parity detection circuit that detects whether the parity of the data demodulated by the data demodulation circuit is correct; an error detection/correction circuit that detects and corrects errors in the demodulated data; and a parity detection circuit that detects and corrects errors in the demodulated data; A magnetic disk device comprising: a read data line for sending data to the data buffer. 2. Detection of a command/data line of 1 byte or more containing parity for each byte used to send and receive data to and from a host device, and whether the parity of the data sent via the command/data line is correct or incorrect. a parity detection/generation circuit that generates a parity; an input/output control unit that controls data transmission and reception between the host device; and a parity control unit that absorbs the difference in transfer speed between the host device and the magnetic disk device. A data buffer that temporarily stores data, an error code generation circuit that generates an error correction code for detecting and correcting errors in write data, and a parity that generates parity of the error correction code generated by the error code generation circuit. a generation circuit; a data modulation circuit that converts the write data and the error correction code into a format to be written on a recording medium including their parities; a write circuit that writes to a recording medium; a read circuit that reads data from the recording medium by a magnetic head via the switching circuit; and a peak detection/pulsing circuit that converts an analog signal of data read by the read circuit into a digital signal. a data demodulation circuit that demodulates the converted digital signal; and a parity detection circuit that detects whether the parity of the data demodulated by the data demodulation circuit is correct or incorrect.
A magnetic disk device comprising: an error detection/correction circuit that detects and corrects errors in the demodulated data; and a read data line that sends data from the error detection/correction circuit to the data buffer. .