JP2607366B2 - Disk device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk device represented by an optical disk device for recording and reproducing digital data in a plurality of sectors on a disk.

In the present invention, when the error is in the first range, the error is corrected by the error correction means, and when the error is in the second range, the error is corrected by the arithmetic means.

[Conventional technology]

When digital data is recorded on an optical disk, a track is divided into a plurality of sectors, and each sector is a unit. Therefore, an error correction code is added to the digital data so that correction can be performed for each sector. An error correction circuit is provided to correct this error.

[Problems to be solved by the invention]

In the conventional device, the error correction circuit is configured so that an error generated in a sector can be corrected up to the maximum correction capability of the correction code, so that not only the configuration is complicated but also the cost becomes high. Was.

[Means for solving the problem]

In order to solve the above problem, the present invention provides a disk device for recording and reproducing predetermined digital data in a plurality of sectors on a disk, a memory for storing the reproduced digital data, and a memory for storing the reproduced digital data. Error correction means for correcting an error in the digital data, and operation means for performing a predetermined operation according to a predetermined program,
The error correcting means corrects the error when the number of errors in the digital data is equal to or less than a predetermined number, and the arithmetic means corrects the error when the number of errors in the digital data is larger than a predetermined number. I have.

[Action]

When the number of errors in the digital data is equal to or less than a predetermined number, the error correcting means corrects the error, and when the number of errors in the digital data is larger than the predetermined number, the calculating means corrects the error.

Therefore, the error correction in the range where the error rate is low can be corrected by the arithmetic means, and the error correction in the range where the error rate is high can be performed at high speed, so that the error correction can be speeded up as a whole. Further, since the size of the error to be corrected by the error correction means is small, the error correction means can be simplified.

〔Example〕

FIG. 1 is a block diagram of the optical disk device of the present invention. In FIG. 1, reference numeral 1 denotes an optical disk, and a modulation / demodulation circuit 2
Is modulated, and a signal reproduced therefrom is demodulated by the modulation / demodulation circuit 2. An error detection and correction circuit 3 adds an error detection code and an error correction code to a recording signal, and detects and corrects an error in a reproduced signal. Reference numeral 5 denotes a CPU as arithmetic means or control means, which controls various circuits, means and the like according to a program stored in a ROM constituting the memory 8. Reference numeral 4 denotes a memory such as a RAM, which stores signals to be recorded and reproduced. Reference numeral 6 denotes a host computer which sends and receives signals to be recorded on and reproduced from the optical disk 1 via the interface 7.

Thus, the track of the optical disc 1 is divided into a plurality of sectors, and each sector has an ID as shown in FIG.
It is composed of an area and a data area. Address information such as a track number and a sector number is recorded in the ID area in advance, and predetermined digital information is recorded and reproduced in a data area corresponding to the address. Therefore, these codes are added to each sector so that data errors can be detected and corrected for each sector.

When a write command is input to the host computer 6 or the CPU 5, digital data to be recorded is transmitted from the host computer 6 via the interface 7 and stored in the memory 4. The error detection and correction (ECC) circuit 3 generates and adds an error detection code and an error correction code to the data stored in the memory 4. The digital data processed in this manner is modulated by the modulation / demodulation circuit 2 by a predetermined method (for example, M ² ), and written into the data area of the sector of the optical disk 1 at the designated address.

Immediately after the write operation, a read operation for confirmation is automatically performed. The signal reproduced from the sector just written on the optical disk 1 is demodulated by the modulation / demodulation circuit 2 and stored in the memory 4. The error detection and correction circuit 3 generates a syndrome of the data stored in the memory 4. Next, the number of errors is determined from the syndrome, and when the number of correctable errors is two or less, the write mode is terminated. If there are three or more correctable errors (including the case where one uncorrectable error has occurred), a write operation is performed again in another sector (alternate sector), and this confirmation is performed in the same manner as described above. Is performed.

FIG. 2 shows the above operation in a flowchart.

Next, a flowchart when a read command is input is as shown in FIG. 3, for example. First, the optical disk 1
Data is reproduced from the sector at the specified address of
After being demodulated by the modulation / demodulation circuit 2, it is stored in the memory 4. The error detection and correction circuit 3 generates a syndrome of the data stored in the memory 4. Next, the number of errors is determined from the syndrome, and when the number of correctable errors is less than three, the errors are corrected by the error detection and correction circuit 3. When the number of correctable errors is four or more (and within the maximum correction capability range (for example, 8)), the CPU 5 temporarily stops the read sequence, reads the syndrome data from the error detection / correction circuit 3, and stores the RAM constituting the memory 8. Transfer to and memorize. Further, the CPU 5 as a calculating means calculates the position and magnitude of the error from the syndrome and corrects the error. When the error correction is completed, the original sequence is continued.

The number of reference errors described above corresponds to the time required for correction. That is, when the time required for the error detection and correction circuit 3 to correct is the number of errors (3) shorter than the trace time of one sector, the error is corrected by the error detection and correction circuit 3 and the number of errors (4) becomes longer. Is corrected by the operation of the CPU 5. As a result, while the data of one sector is being read, the operation of correcting the data read from the immediately preceding sector by the error detection and correction circuit 3 is repeated, and the data of each sector can be read continuously ( (Fig. 4).

The number (2) of errors used as a reference at the time of reproduction (verify read) for confirmation immediately after recording is set smaller than the maximum correction capability (8). As a result, a margin for an increase in the number of errors due to a secular change or the like after recording can be further increased.

The present invention can be applied to a case where information is recorded / reproduced on a disc other than the optical disc.

[Effect] As described above, according to the present invention, when the number of errors in digital data is equal to or less than a predetermined number, the error correction means corrects the error, and when the number of errors in digital data is larger than the predetermined number, the operation is performed. Since the means is configured to correct the error, the error correction in the low error rate range can be corrected by the arithmetic means, and the error correction in the high error rate range is performed at high speed. Speed can be increased. Further, since the size of the error to be corrected by the error correction means is small, there is an effect that the error correction means can be simplified.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a disk drive according to the present invention, FIGS. 2 and 3 are flowcharts thereof, and FIG. 4 is an explanatory diagram of its sectors. DESCRIPTION OF SYMBOLS 1 ... Optical disk 2 ... Modulation / demodulation circuit 3 ... Error detection and correction circuit 4 ... Memory 5 ... CPU 6 ... Host computer 7 ... Interface 8 ... Memory

Claims (1)

(57) [Claims] 1. A disk apparatus for recording and reproducing predetermined digital data in a plurality of sectors on a disk, a memory for storing the reproduced digital data, and correcting an error in the digital data stored in the memory. Error correction means, and arithmetic means for performing a predetermined operation in accordance with a predetermined program, wherein when the number of errors in the digital data is equal to or less than a predetermined number, the error correction means corrects the error, and corrects the error in the digital data. The disk device, wherein the arithmetic means corrects the error when the number is larger than a predetermined number.