JPH10308080A - Information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the corrective ability for the burst error of record data caused by a defect, dust or flaw of a disk and to realize an information recording medium capable of enhancing the reliability of data. SOLUTION: Error corrective codes generated for the assembly of data collected by a specified number from each sector included in an error corrective block are dispersed and arranged among plural sectors of the above error corrective block. By disposing these sectors continuously on the medium, the reproducing device can execute error correction using the data in this error corrective block and error corrective codes dispersed among plural sectors, and increase the burst error correcting length.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for correcting an information error in an apparatus for recording and reproducing information on a disk-shaped recording medium, and more particularly to a method for correcting an information recording medium recorded by the method. To provide.

2. Description of the Related Art An optical disk has been used as a new means for recording large-capacity information. An optical disk records and reproduces information by using the change in the optical rotation angle due to the magneto-optical effect and the difference in the reflectance due to the difference in the heating temperature.
A rewritable non-rewritable (ROM) disk can be easily manufactured, and the rewritable disk recording / reproducing apparatus can reproduce information. This feature allows a large amount of information to be distributed at low cost, and has been established in international standards as an important technology in the multimedia age.

However, an optical disk has a higher error rate than a conventional magnetic disk and is premised on the use of an error correction code. The types of error occurrence on the optical disc are classified into random errors and burst errors. The random error is caused by noise or the like, and an error occurs in a bit unit. A burst error is caused by a defect, dust, or scratch on a disk, and erroneous consecutive bits. Fig. 6 shows the configuration of a sector on an ISO standard 3.5 "optical disk. A sector 10 is composed of 512 bytes of user data, 4 bytes of vendor unique data, 4 bytes of an error detection code (CRC) using a cyclic code, and 4 bytes of read / write data.
Error correction code (ECC) parity by Solomon code 8
It is composed of 0 bytes. The error correction code generation sequence divides a total of 520 bytes of user data, vendor unique data, and CRC into 104 bytes at intervals of 5 bytes, and generates an ECC parity of 16 bytes. An error correction sequence of the sequence is formed (5 interleaves). The correction capability of the error correction code can correct a random error up to an 8-byte error in each correction sequence, and can correct a 40-byte error in the entire sector. In addition, a burst error has a capability of correcting consecutive 40 bytes in one sector. However, in an actual optical disk, a random error and a burst error occur simultaneously, and a burst error within the correction range is fixedly generated. When a random error occurs therein, the number of random errors is within the correction range. However, as a result, correction becomes impossible. Therefore, it is necessary to eliminate fixed burst errors as much as possible during data recording. Therefore, a rewritable disk device employs a method of rewriting data in another location when an error during information reproduction immediately after recording exceeds a predetermined number, even within the range of error correction capability. However, such rewriting cannot be performed on a ROM disk in which information is recorded in pre-pits at the time of manufacturing the disk.
One parity sector is provided for each sector, and data at the same position in each sector is subjected to exclusive OR (EOR) for each byte and recorded in the parity sector. However, in this parity system, the recording efficiency is reduced because a parity sector is required separately from the data sector, and since only one byte error can be corrected in one correction sequence, a burst error and a random error are combined. When they occur, they tend to be uncorrectable, requiring higher error correction capability.

In order to solve the above problems, in the present invention, an error correction code sequence is distributed and arranged between sectors which are blocks of information recording. The playback device has a storage unit for storing data of a plurality of distributed sectors and a correction unit. As another means, two systems are provided: a sequence in which error correction code sequences are dispersedly arranged in sectors, and a sequence in which error correction code sequences are dispersedly arranged between sectors. In the reproducing apparatus, storage means for storing data of a plurality of sectors, first error correction means for correcting data dispersed in a plurality of sectors, and second error correction means for correcting data dispersed in the sectors. Correction means. Alternatively, it has one error correction circuit for sequentially correcting data distributed in the sector and correcting data distributed in the sector.

The data sequence for generating the error correction code is composed of 0 sector, 1 sector, 2 sectors... N sector, 0 sector.
The data is used one byte at a time, and the generated error correction code is also recorded on the recording medium following the data.
In the reproducing apparatus, reproduced data from sector 0 to sector n is stored in the storage means, the data and the error correction code are read out from the storage means in the same order as when the error correction code was generated, and the error correction means corrects the data. The corrected data is read from the storage means in the order of the sectors and output to the host device. In addition, an error correction code is generated based on the data in the sector, and the generated error correction code is recorded in the same sector. In the reproducing apparatus, the reproduced data from sector 0 to sector n is stored in the storage means, and the data and error correction code in each sector are read out from the storage means, and correction in the sector is performed. After performing the correcting operation for all the sectors, the data of the data series dispersed between the sectors and the error correcting code are changed to 0, 1, and 2 sectors.
··· Reads from the storage means one byte at a time in the order of n sectors, 0 sectors. By performing double error correction on 1-byte data, the correction capability is improved. Alternatively, error correction within a sector is performed while storing data from sector 0 to sector n in the storage means, and when an error that cannot be corrected occurs, error correction between sectors is performed.

EXAMPLES The present invention will be described below with reference to examples. FIG.
FIG. 1 shows a first example of a sector configuration according to the present invention. In the figure, the basic data structure is ISO 3.5 ″ shown in FIG.
This is the same as the optical disk standard, and has a configuration of 512 bytes of user data, 4 bytes of vendor unique data, 4 bytes of error detection code (CRC), and 80 bytes of error correction parity. SYNC and RESYNC for synchronizing data are also recorded on the actual disk at the same time, but are omitted because they are not directly related to the present invention. Also, an ID portion in which a track number and a sector number are recorded is omitted. In FIG. 1, 600 bytes of data to be recorded in one sector are arranged in 5 rows from 0 to 4 and in 120 columns from 0 to 119. 1 row 0 column, 2 row 0 column... 4 row 0 column, 0 row 1 column, 1 row 1 column... Here, the inter-sector dispersion according to the present invention is set to four sectors. The symbol D represents user data, vendor unique data, and CRC, and the symbol P represents parity. The first half of the suffix of each symbol indicates a sector number, and the second half of the suffix indicates the order of recording / reproducing in the sector.
A description will be given using data D0,0 as an example. The same correction sequence as D0,0 is composed of D1,0, D2,0, D3,0, D0,20, D
1,20, D2,20, D3,20, D0,40, ... D3,500, P0,
0, P1,0, P2,0, P3,0, P0,20 ... 120 of P3,60
It is a byte, consisting of 104 bytes of data and 16 bytes of correction code. FIG. 2 shows an example of the reproducing apparatus. In FIG. 1, 1 is an optical disk, 2 is a spindle motor, 3 is an optical pickup, 4 is a demodulation circuit, 5 is a memory circuit, 6 is a data memory address control circuit, and 7 is an error correction circuit. In actuality, in addition to this, there are a moving mechanism and a positioning mechanism of the optical pickup, a servo circuit for focus control of laser light, and a clock recovery circuit for data detection. It is not shown in the figure because it does not affect the operation. The optical disk 1 is rotated by a spindle motor 2 so as to have a constant angular velocity or a constant linear velocity. The optical pickup 3 is controlled by the above-described moving mechanism and positioning mechanism (not shown) so that the track of the optical disc 1 is irradiated with the laser beam, and the focus control circuit (not shown) also controls the recording surface of the optical disc 1. Control is performed so that the laser light is focused. A pit train obtained by modulating recording data by a predetermined modulation method is recorded on a track of the optical disc 1. A pit train reproduced signal of the optical pickup 3 is demodulated by a demodulation circuit 4 according to a predetermined rule. It is restored to the data string before modulation. The restored data string is stored in the data memory 5 in a predetermined number of sectors (four sectors in the case of FIG. 1). Thereafter, the data is read from the data memory 5 in the error correction circuit 7 and error correction is performed. Although an error correction algorithm is already well known and will not be described here, the data of the above-described correction code generation sequence is sequentially read and input to the error correction circuit 7. In the example of FIG. 1 in which four correction sectors are distributed, there are 20 correction code generation sequences. Therefore, there is a method of providing a number of correction circuits corresponding to each sequence. It is possible to adopt a configuration in which the error correction operation of a sequence or a plurality of sequences is performed simultaneously, and the error correction operation of the entire sequence is performed by repeating this operation. According to this arrangement, the number of data and the number of parities constituting the correction code are the same as those in the ISO format shown in FIG. 6, so that the random error correction capability is the same, but the burst error correction capability is greatly improved. I do.
While the burst error correction length in FIG. 6 of the conventional example is 40 bytes, the burst error correction length in FIG.
Increase to 60 bytes. FIG. 3 shows another second embodiment. In this example, two types of correction codes are provided for one piece of data, the first correction code being generated in a distributed manner between the sectors as in the example of FIG. 1 and the second correction code generated in the sector. ing. The first correction codes distributed between the sectors are distributed over four sectors as in the example of FIG. 1, and one sector is similarly represented by an array of 5 rows and 120 columns. Here, the data is D, the parity by the first correction code is P, and the parity by the second correction code is Q. The meanings of the subscripts added to data and parity are the same as in FIG. Here, the correction codes related to D0,0 are D0,0, D1,0, D2,0,
D3,0, D0,20, D1,20, D2,20, D3,20, D0,40, ...
..104 data of D3,500, and P0,0, P1,0, P2,0,
P3,0, P0,20... P3,35 are composed of 8 parities. On the other hand, the second correction code formed in the sector is D0,
0, D0, 5, D0, 10, D0, 15, D0, 20, D0, 25, D0, 30,
104 data of D0,35, D0,40, ... D0,515, P
0,0, P0,5, P0,10, P0,15, P0,20 ... 8 parity of the first correction code of P0,35, Q0,0, Q0,5, Q0,1
It is composed of 8 parities of 0, Q0, 15, Q0, 20... Q0, 35. Since both correction codes can correct up to a 4-byte error, correction is performed with the second correction code, and then correction is performed again with the first correction code. In the random error correction, since the second correction code sequence includes a plurality of data of the first correction code sequence, if an error occurs in five of the data included in both of them, either one of the two data has an error. Correction cannot be performed even with a correction code. Therefore, the random error correction capability is lower than the conventional system. However, with regard to burst errors, even if a 16-byte burst error occurs in the second error correction sequence and cannot be corrected, these errors are corrected by the first error correction sequence. Length is 8
Up to 0 bytes are allowed. This is twice as large as the conventional method. Next, a third embodiment will be described with reference to FIG.
Also in this embodiment, the error correction code is shown in FIG.
As in the example of the first example, the first error correction code distributed between the sectors and the second error correction code configured in the sector are provided, but the first error correction code included in the second error correction code sequence is provided. In order to reduce the number of one code sequence data, the data constituting the first error correction code sequence is shifted in the sector. The data structure of the sector is the same as the previous example,
It is composed of a 520-byte data part and an 80-byte parity part, has five second error correction sequences, and represents one sector in an array of five rows and 120 columns. One error correction sequence is composed of a 104-byte data part and a 16-byte parity part. Of the 16-byte parity, eight-byte parity is a first error correction code distributed between sectors to be described later. This is used in the generation sequence of the second error correction code completed in the sector, and is treated in the same manner as data. Therefore, the second
Is regarded as an 8-parity code for 112 data. On the other hand, the first
FIG. 4 shows an example in which the error correction code is distributed over 8 sectors, but is composed of 104 bytes of data and 8 bytes of parity. In the figure, taking the head data of the first sector (sector 0), that is, the data of row 0 and column 0 as an example, the generation sequence 11 of the first error correction code distributed between sectors including this data is Data in row 0 and column 0 of second sector (1 sector), 3rd sector (2 sectors)
0 row 0 column data: 8th sector (7 sectors)
0 row 0 column data, 1 of the first sector (0 sector)
Data in row 8 column, row 8 in second sector (1 sector)
Column data: 1 row 8 of the 8th sector (7 sectors)
This is performed while shifting data by one row in the sector in the order of column data, data of 2 rows and 16 columns of the first sector (sector 0), and returns to row 0 when the data reaches 4 rows. By repeating this, data up to 2 rows and 96 columns is used, and the 8 parities added thereto are arranged in 3 rows and 104 columns of each sector. An error correction code sequence is formed for other data according to the same rule, and a total of 40 sequences are generated. On the other hand, as the generation sequence 12 of the error correction code completed in the sector, five sequences are generated for each sector for each row, and the added parity is arranged from 112 columns to 119 columns. The number of data and parity in one series of the error correction codes dispersed among the sectors included in the same sector in the dispersed eight sectors is 14 and is shifted by one row. Therefore, the number of data included in the same row is two or three. Therefore, when data commonly included in the two types of error correction code sequences are simultaneously erroneous, the two sequences are not simultaneously uncorrectable, and the random error correction capability can be improved. Regarding the burst error correction capability, even if 164 bytes of data are continuously incorrect in a sector,
Correction is possible with error correction codes distributed between sectors.
As described above, the error correction capability of both random and burst can be improved by using two systems of error correction codes, but the correction capability can be further enhanced by performing repetitive correction. That is, the second in the sector
The error pattern which cannot be corrected by the error correction by the error correction code of the second error correction code and the error correction by the first error correction code between the sectors is corrected by the second error correction code in the sector again. Exists. By repeating this further, correctable data increases. On the other hand, when the error occurrence probability is low, only the correction by the second error correction code in the sector is performed at all times, and the first inter-sector correction is performed only when an uncorrectable state occurs. Error correction using an error correction code may be performed. Next, a recording method will be described. FIG. 5 shows a block diagram of the recording circuit. Again Figure 2
Like the above, the portions which are not directly related to the present invention are omitted. The same parts as those in FIG. 2 are denoted by the same reference numerals. Data sent from a higher-level device (not shown) is stored in the memory circuit 5, and when data of a predetermined number of sectors for dispersing the error correction code is accumulated, an error correction code generation circuit 8 generates an error correction code. In the example shown in FIG. 1, data at a predetermined position is read out by the memory address control circuit and is input to the error correction code generation circuit 8. When a predetermined number of data is input and a parity is generated, the parity is read from the error correction code generation circuit 8 and stored in a predetermined position of the memory circuit 5. This operation is performed for all code sequences, and when all parities are generated, the drive device is set in a recording state, and data and parities of all sectors stored in the memory circuit are subjected to predetermined modulation by the modulation circuit 9 to perform optical modulation. Is modulated and recorded on the optical disc 1. If the data to be recorded sent from the host device cannot be recorded by one of the above operations, the recording is performed by repeating this. If the data to be recorded is less than the number of recordable data of one operation described above, that is, the number of sectors to be dispersed, the missing data is filled using pseudo data, for example, fixed data, and recording is performed. When two types of error correction codes within a sector and between sectors are used as in the embodiments described with reference to FIGS. 3 and 4, after a predetermined number of sectors of data are stored in the memory circuit, An error correction code dispersed between them is generated, and then an error correction code completed within a sector is generated and recorded. In the recording method described above, since the recording according to the present invention can be performed for each set of data instructed by the higher-level device to perform recording, the present invention can be applied to a write-once medium or a rewritable medium. Further, at the time of reproduction, unnecessary data need not be read only for correction, so that the data read time can be reduced. Furthermore, by managing the order of the sector positions on the medium on which writing is performed, the sectors to be actually recorded need not be continuous on the medium, and the medium can be effectively used. Note that FIG.
Shows a recording circuit using a laser power modulation method. However, in a magneto-optical disk drive, a magnetic field modulation method that irradiates a constant recording laser beam to change the magnetic field polarity of a magnetic head according to recording data, and a laser power and magnetic field The same is realized in a method of modulating both. Next, as another recording method, when all the data to be recorded on the medium is known in advance, such as when producing a read-only medium, continuous sectors on the medium are independent of the data collection unit. The present invention can be applied and recorded every time. In this recording method, it is desirable to set the number of sectors for dispersing the error correction code to the number of sectors that can be recorded in one track of the medium or the number of sectors obtained by equally dividing the number of sectors by an integer value. With such a setting, the head and block of the sector to be corrected during reproduction can be easily recognized, and the correction operation can be completed in one track. The tracks and sectors at this time need not necessarily be physical tracks and sectors defined by one round of the medium. In a medium in which the rotation speed of the medium is constant and the recording / reproducing data cycle is constant, the number of sectors in the physical track is constant from the inner circumference to the outer circumference. In a medium that is divided into multiple zones and the number of revolutions and the recording / reproducing data cycle are changed for each zone, the number of sectors in a physical track varies depending on the media diameter or zone, so a fixed set of sectors is defined as a logical track. In many cases, physical tracks are not used. Therefore, in this case, the number of sectors constituting the logical track or the number of sectors obtained by equally dividing the number of sectors by an integer value is used.
It is desirable to set the number of sectors in which error correction codes are distributed. The recording device in this case can also be realized by the configuration shown in FIG. 5, but as another realizing means, a storage device capable of storing all data and parity to be recorded is provided.
Parities for all data can be generated in advance, stored in a storage device, and read and recorded continuously. The generation of the error correction code at this time can also be performed by software operation by a computer. Also, in any of the embodiments described so far, the error correction code can be realized by using the same error correction code as that of the conventional sector configuration shown in FIG. Circuits and correction circuits can also be used. Therefore, it is easy to share the recording device, the reproducing device, and the recording / reproducing device with the write-once or rewritable recording medium and the read-only medium of the conventional format to which the present invention is not applied. Although the present invention has been described based on the embodiments, the sector configuration, the configuration of the error correction code, the number of sectors to be dispersed, and the like are all examples, and the present invention is not limited to these. not,
The present invention is also realized with other sector configurations, error correction codes, and numerical values.

As described above, according to the present invention,
Burst error correction capability can be increased, and the reliability of recorded data can be increased. Further, since the present invention can be applied to each recording file and can be easily recorded on a drive device, it can be used not only for a read-only disc but also for a write-once disc and a rewritable disc, thereby improving the reliability of recorded data. Can be.

[Brief description of the drawings]

FIG. 1 shows a first embodiment according to the present invention.

FIG. 2 shows a configuration example of a reproducing apparatus according to the present invention.

FIG. 3 shows a second embodiment according to the present invention.

FIG. 4 shows a third embodiment according to the present invention.

FIG. 5 is a configuration example of a recording apparatus according to the present invention.

FIG. 6 shows a conventional sector configuration.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical disk, 2 ... Spindle motor, 3 ... Optical pickup, 4 ... Demodulation circuit, 5 ... Memory circuit, 6 ... Address control circuit, 7 ... Error correction circuit, 8 ... Error correction code generation circuit, 9 ... Modulation circuit, 10 ... Sector, 11 ... Generation sequence of first error correction code, 12 ... Generation sequence of second error correction code

Continued on the front page (51) Int.Cl. ⁶ Identification code FI G11B 20/18 572 G11B 20/18 572F

Claims (2)

[Claims] An information recording medium on which data is recorded by forming a sector serving as a recording unit with a set of a predetermined number of data, wherein the reproducing apparatus is provided for each error correction block comprising a plurality of sectors. When performing error correction using an error correction code generated for a set of data collected by a predetermined number from each sector included in the error correction block, the burst error correction length of the error correction code can be increased. An information recording medium, wherein the error correction code is dispersedly arranged in a plurality of sectors in the error correction block, and the sectors are continuously arranged and recorded on a recording medium. 2. An information recording medium on which data is recorded by forming a sector serving as a recording unit with a set of a predetermined number of data, wherein the reproducing apparatus comprises: Error correction using a first error correction code generated for a set of data collected by a predetermined number from each sector included in the error correction block and a second error correction code generated in each sector The first error correction code is distributed and arranged in a plurality of sectors in the error correction block so that the burst error correction length of the first error correction code can be increased. An information recording medium characterized in that a second error correction code is arranged and recorded in a sector including data for generating the same, and the sector is arranged and recorded continuously on the recording medium.