JPS62200576A - Normal/defective condition deciding system for sector data - Google Patents

Abstract

PURPOSE:To improve the reliability of data and shorten the processing time necessary for correcting to an error by setting a normality decision reference in a value less than the number of correctable errors in respective code strings to decide the normality/defectiveness of data exactly. CONSTITUTION:A data read out from a recording medium 101 by a recording and reproducing means 102 is modulated in a modulation and demodulation part 103 and stored in a storage means 104. Thereafter, the numbers of errors in respective code strings are calculated in a error-correction arithmetic part 105. In case the number of correctable errors among the X-pieces of parity data attached to respective code strings is N, the integer Ns set at a value smaller than the N and the calculated number of errors are compared and decided which is larger. In case the number of errors in the code string exceeds the Ns, the occurrence of error is judged to be probable. When not exceeding the Ns, no error is judged. And both results are informed to a control part 106 to end the checking as to the normality/abnormality of the recording. As a result, a fault in case the number of errors is close to a value which is the limit of the correction can be eliminated. Therefore, the decision of normality- abnormality of data is made exact.

Description

[Detailed Description of the Invention] <Technical Field of the Invention> The present invention relates to RA of sector data on magneto-optical disks, etc.
The present invention relates to an improvement in a sector data quality determination method during W (Read After Write).

<Prior art and problems> Figure 3 shows the formant of a sector. One sector is divided into multiple code sequences 310, 320, 330°, etc., and each code sequence has a data part and an error check. It consists of a code section. For example, code sequence 310
The data section 310a and the error check code section 310
Consists of b. This sector format shows the case where one hide unit is used as a constituent block.

In this sector configuration, each code sequence is 310°320.3
30. --- error check code section 310b, 32
If more 0b, 330b, --- are taken, data parts 310a, 320a are obtained.

330a, --- can deal with more errors, but
The ratio of the error check code section to the code sequence increases, and data efficiency decreases. Therefore, the ratio of the data part to the error check code part in the code sequence is determined by taking into consideration the characteristics of the recording medium, the error correction method, and the like.

In the conventional sector data quality determination method, if the number of errors is less than or equal to the number of errors that can be corrected in the error check code section, the sector data is judged to be "good". However, if the number of errors is close to the limit that can be corrected by the error check code section in the RAW check, that is, the check when reading immediately after writing, then a certain amount of time has passed since writing due to dust adhering to the recording medium, etc. During normal playback, the number of errors will exceed the limit and correction will become impossible. In particular, the S/N of magneto-optical disks etc.
This effect is significant in the case of recording media with poor quality.

<Object of the Invention> The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sector data quality determination method that is more reliable than the conventional method.

<Embodiment of the invention> An example of the functional block configuration for carrying out the invention is shown in the first example.
FIG. 2 shows an example of a RAW check processing procedure, and FIG. 3 shows an example of a conceptual configuration of a sector.

In FIG. 1, lot indicates a recording medium on which recording is performed, and 102 indicates a recording/reproducing means for recording or reproducing data on the recording medium 101. 103 is a modulation/demodulation unit that modulates data reproduced from the recording medium 101 by the recording/reproducing means 102, and
The data to be recorded is modulated. 104 is a storage means that stores reproduced data from the modulation/demodulation section 103, stores data to be transferred to the modulation/demodulation section 103, and stores data to be recorded transferred from the host device 107 and data to be transferred to the host device 107. Stores the playback data that should be played. The data stored in the storage means 104 is checked by the error correction calculation section 105 at the time of reproduction to see if there are any errors in the recorded data. Reference numeral 106 denotes a control unit, which includes a modulation/demodulation unit 103 and a storage unit 104 . Controls the error correction calculation unit 105.

FIG. 3 shows a conceptual arrangement of data in sectors, DI, D2. ..., Dm stores m pieces of user data to be actually recorded as P II , P 12
.

-, P+ X, P2+, P22. -, P
2 x, P31. -- represents parity data for error detection and correction of user data during reproduction. The sector includes a plurality of code sequences 310, 320, 330 . -, and each code sequence is composed of a data part and an error check code part. For example, code sequence 310
The data section 310a and the error check code section 310
Consists of b.

When recording data, an error correction calculation unit 10 is used for each code sequence.
5, an error detection and correction code is added. DI of the code sequence 310 in the first column, D2. The parity for error detection and correction of n data strings of -・-1Dn is P II
, P 12. −, P lx, followed by Dn+I of the code sequence 320 in the second column, D n +2, −,.

Parity data for error detection and correction of n data strings of D2 n are P 2+ , P 22, -,
P 2 x, and the same applies to subsequent columns.

The data recorded on the recording medium 101 is read out immediately after recording, and an error correction calculation unit 105 performs a check (RAW check) to see if the recording has been performed correctly. This RAW check process will be explained below using the flowchart of FIG.

Data read from the recording medium 101 by the recording/reproducing means 102 is demodulated by the modulation/demodulation section 103 and stored in the storage means 104. The error correction calculation unit 105 calculates the number of errors in the stored data for each code sequence (S201).

Now, if the number of errors that can be corrected with X parity data added to each code sequence is N, then a predetermined integer Ns smaller than N and the calculated number of errors are A determination is made as to the size of the image (S202). If the number of errors in a certain code sequence exceeds Ns even though it is read out immediately after recording, it is determined that that sector contains the risk of causing an error, and a notification indicating that the sector has an error is determined. After informing the control unit 106, the RAW check ends. (S 205).

The number of errors is calculated for all code sequences, and when it is confirmed that there are no more than Ns errors in any code sequence, the controller 106 is informed that there are no errors,
The RAW check ends (S203, 5204).

<Effects of the Invention> As explained above, in the present invention, the pass/fail criterion for each code sequence in a sector is set to a value smaller than the number of errors that can be corrected in each code sequence. When close to the possible limit value, the RAW check can reliably determine pass/fail, increasing the reliability of the data. Furthermore, since the number of errors that is used as a criterion for canceling the number of correctable errors is limited, the processing time for error correction can be shortened.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a functional block configuration of an embodiment of the present invention,
Figure 2 is a flowchart showing the processing procedure of the embodiment of the present invention;
The figure is a diagram showing a conceptual configuration of sectors. 101...Recording medium 102-Recording/reproducing means 10
3-Modulation/demodulation section 104--Storage means 105--Error correction calculation section

Claims (1)

[Claims] In a sector data quality determination method in which a sector is divided into multiple code sequences to which error correction codes are added, and the quality of sector data is determined according to the number of errors in each code sequence, the quality determination criteria for each code sequence described above is is set to a value smaller than the number of errors that can be corrected in each of the code sequences.