JPS60261076A - Data format generating method - Google Patents

Abstract

PURPOSE:To improve the data error correcting capability by making the number of sections made by dividing equally a data block an integer multiple of a code length within the error correction range of the 1st order error correcting code. CONSTITUTION:A data format written in a recording medium is split equally into n-set of sections 1-n for one data block. The sections 1-n consist each of a data part, 1st order error correcting code ECC and 2nd order ECC. The 1st order ECC, in this case, uses pointer information and has double missing correcting capability. The number of sections (n) is an integer multiple of the code length within the error correction code range of the 1st order ECC. The read data is fed to a demodulation circuit 6, an ECC two-decoding circuit 8 outputs the corrected data and error position to a read data buffer 7 and the pointer information is fed to the ECC 1-decoding circuit 9. Thus, the correcting capability of data error generated in each section is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides a data block in which a data block is equally divided into a plurality of sections, and each section includes a primary error correction code and a second error correction code.
The present invention relates to a data format in which a secondary error correction code is a constituent element, and particularly relates to a data format creation method in which the number of cefsilanes is an integral multiple of the primary error correction code length.

Various measures for detecting and correcting code errors in digital data have been put into practical use in information processing devices that handle digital data. The main one is Entertainment Correction Code (ECC)
This is a method using

ECC includes single erasure correction, single error correction, double error detection, double erasure correction, etc. ECC has various correction capabilities depending on the purpose of use, with the number of detected and corrected digital code errors as the correction capability of ECC. has been put into practical use, but there has been a desire to put into practical use a method for creating a data format that has the ECC capability left behind in information processing devices, especially storage devices, and is capable of reproducing high-quality data. .

[Conventional technology]

A conventional data format (magnetic disk, optical disk, etc.) having an ECC function will be explained with reference to one drawing.

FIG. 2(A) shows a data format on a datablong medium configured by a conventional method, and FIG. 2(B) shows a detailed view of the data structure of the data format of FIG. 2(A).

Error correction when reading data recorded in a data block configured in the data format shown in FIG. 2 involves correcting an error detected by an error check code (hereinafter referred to as CRCC) using ECCl.

There are cases where errors are corrected using only ECCl, and CR
(: When correcting errors using C and ECCl, data errors occurring in up to two sections in one data block, that is, up to two sections (1) to Correct in units of codewords ■ to O (double erasure correction).

On the other hand, when errors are corrected using only ECCl, it is possible to correct a data error occurring in one sector (single error correction) for each codeword (1) to (0).

(Problem to be solved by the invention) However, when errors are corrected using CRCC and ECCl.

If a data error occurs in three or more sections in one data block, it is impossible to correct the error even if the data error is distributed into two data errors for each codeword Φ~[stock]. becomes.

On the other hand, when correcting data errors using only ECCl, if two or more data errors occur in one code word, there is a problem that data errors other than one cannot be corrected or may be incorrectly corrected. There was a point.

[Means for solving problems]

An object of the present invention is to realize a new data format creation method that solves the above-mentioned problems. 1 generated from a part of
With the following error correction code.

In a data formant whose constituent elements are a part of data and a secondary error correction code generated from the primary error correction code, the number of sections is determined by the code length that is the error correction range of the primary error correction code. This problem is solved by the data format creation method according to the present invention in which the data format is an integer multiple of .

[Effect]

In other words, the number of sections constituting a data block is expressed as linear E
It is an integer multiple of the code length that is the error correction range of CC, and each section has a data part and a part generated from a part of the data.
2 generated from the next ECC, part of the data, and the first ECC
The error correction range of the primary FCC is set as a column diagonal to the section column, and the error correction range of the secondary ECC is set as a section column.The primary ECC and secondary ECC are combined to correct data errors. By performing the correction, it is possible to create a data formant that has error correction capabilities that are much improved over conventional capabilities.

〔Example〕

The gist of the present invention will be specifically explained below with reference to an embodiment shown in FIG.

FIG. 1(A) is a block diagram showing one embodiment of the writing circuit according to the present invention, FIG. 1(B) is a block diagram showing one embodiment of the reading circuit according to the present invention, FIG. 1(C) 1(A) shows a data formant recorded on a medium by the write circuit of FIG. 1(A), and FIG. 1(D) shows an explanatory diagram of an error correction situation according to the present invention.

The same symbols indicate the same objects or contents throughout the figures.

The write circuit in FIG. 1(A) is as follows.

Data buffer 1 that temporarily stores the transferred data from the upper bag f& (not shown) ECCl code circuit 2 that creates the primary ECG from the transferred data 2 E.C.C.
ECC2 code circuit 3 for creating the data; write data buffer 4 for temporarily storing the transfer data, primary ECC, and secondary ECG as write data; for writing the output of the write data buffer 4 to a medium (not shown) Modulation to data (including modulation to serial data)
It consists of a modulation circuit 5° which outputs to a light amplifier (not shown).

Also, the reading circuit in FIG. 1(B) is as follows.

Recovering the read data from the read amplifier (not shown)
(including demodulation to parallel data) 1-round demodulation circuit 6° Read data buffer 7° that temporarily stores the read data demodulated by the demodulation circuit 6 Performs secondary ECG decoding calculations from the output of the demodulation circuit 6 ECC2 decoding circuit 8 that outputs the corrected data to the read data buffer 7゜The primary ECC decoding operation is performed using the pointer information from the ECC2 decoding circuit 8, the error position information required when performing erasure correction, and the output of the read data buffer 7. ECCl decoding circuit 9° which performs correction and outputs the corrected data to the data buffer IO; data buffer 10° which temporarily stores read data corrected by the secondary ECG and outputs it to a host device (not shown); It consists of

The data former node that has written to a medium (ri!J not shown), such as a magnetic disk or an optical disk, via the write circuit shown in FIG. 1(A) is as shown in FIG. 1(C). Divide data errors equally into n sections (
It is divided into 1) to (n).

Also, each section (1) to (n) is the data part and primary ECC.
, secondary ECC. Also, primary ECG.

The error correction ability of both secondary ECC is one data error (
1 byte). (single error correction) However, primary ECC
is assumed to be capable of double erasure correction (correction of two data errors) using pointer information. Furthermore, 1st EC
Since the C, secondary ECC constitutes an independent data string as each codeword series, the range of correction is within each codeword series.

In this embodiment, the number of sections into which one data block is divided is n.

Determine as n=kXm (where: an integer). Note that m indicates the code length (bytes) that is the error correction range of the primary ECC, that is, the code word length of the primary ECC.

Next, an error correction method when reading the data format created and recorded in the above manner will be explained.

In this embodiment, ni=l and m=6 bytes.

An example of the configuration of one data block is shown in FIG. 1(D).

In the figure, the first circle is data in byte units, and the double circle is primary FC.
C (2 hides for each codeword).

Triple circles indicate secondary ECC, and diagonally shaded single circles indicate data in which an error has occurred.

The error correction range of the primary ECG is a data string connected with a dotted line, and the error correction range of the secondary F and cc is a data string connected with a solid line.

Now, section (1) is fixed at 1f, section (2) ~ (
In the situation where two data errors occur in 4),
First, the data in section (1) is read in order, the read data is manually input to the demodulation circuit 6, and the demodulated data is output to the read data buffer 7 and the ECC2 decoding circuit 8.

The ECC2 decoding circuit 8 performs a decoding operation on the subsequent data.

Detects that an error has occurred in the data of codewords ■ to ■. Incidentally, if all data of one data block is output to the read data buffer 7.

The ECC2 decoding circuit 8 starts a correction operation.

The ECC2 decoding circuit 8 calculates the error data position of the code word 10 column, outputs the corrected data and the error position to the decode buffer 7, and also outputs a message indicating that an error has occurred in the data of the code word 0 to 0 columns. The information (pointer information) is output to the ECCl decoding circuit 9.

When the correction operation of the ECCZ decoding circuit 8 is completed, the data in the read data buffer 7 is transferred to the data buffer 10 and the EC,
It is output to the C1 decoding circuit 9. At this time, the ECCl decoding circuit 9 outputs code words (a), (b), and (c).

Detects that an error has occurred in the data of (to).

Furthermore, after outputting all the data, the ECCl decoding circuit 9 starts the correction operation. In addition, the BCCI decoding circuit 9 sequentially calculates the error data position for the code word (c) and (f) columns,
The corrected data and error position are output to the data buffer 10.

Next, the ECC1 decoding circuit 9 uses the pointer information to sequentially calculate corrected data for the data in the code word (a) and (b) columns by double erasure correction operation, and outputs the corrected data and error position to the data buffer 10. .

As described above, two data errors occurring in each of sections (2) to (4) and one (Ii1) data error occurring in section (1) can all be corrected by the primary ECC and secondary ECC.

〔Effect of the invention〕

According to the present invention as described above, the data error correction ability is further improved and high quality data can be reproduced.

[Brief explanation of drawings]

FIG. 1(A) is a block diagram showing one embodiment of a write circuit according to the present invention. FIG. 1(B) is a block diagram showing one embodiment of a reading circuit according to the present invention. FIG. 1(C) shows a data formant recorded on a medium by the writing circuit of FIG. 1(A). FIG. 1(D) is an explanatory diagram of an error correction situation according to the present invention. FIG. 2(A) shows a data format on a medium of a data block constructed using a conventional method. FIG. 2(B) is a detailed diagram of the data structure of the data format of FIG. 2(A). are shown respectively. In fig. 1.10 is a data buffer, 2 is an ECCl code circuit. 3 is an ECC2 code circuit. 4 is a write data buffer. 5 is the change side circuit, 6 is the return circuit. 7 is a read data buffer. 8 is an ECC2 decoding circuit, 9 is an ECCl decoding circuit. are shown respectively. , 90 ■ ■ ○ ■ し す こ . , 8

Claims (1)

[Claims] A data block consisting of a string of data that can be handled as one is divided equally into a plurality of sectors, and each section contains a primary error correction code generated from a part of the data, and a part of the data. and a secondary error correction code generated from the primary error correction code, the number of sections is an integral multiple of the code length that is the error correction range of the primary error correction code. A data format creation method characterized by: