JPH09213010A - Discoid recording medium, recorder and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform highly reliable recording and reproducing without lowering transfer rate at the time of writing data. SOLUTION: On the discoid recording medium having plural tracks formed in a concentric circular shape or a helical shape on the disk surface, each being divided into plural areas where data is written individually as a unit par area, the plural areas are divided into N groups in unit, and M (N>M) areas out of these groups are used for writing user data as user areas. The remaining L (L=N-M) areas are used for writing error correcting codes from error correcting circuits 3 and 4 for the user data written in the M user areas as error correcting areas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc type recording medium such as an optical disc and an apparatus for recording or reproducing user data on the medium.

[0002]

2. Description of the Related Art Conventionally, in an optical disk device, a plurality of tracks are concentrically or spirally formed on the disk surface,
Further, the track is divided into a plurality of sectors, and user data is recorded and reproduced in sector units. In the recording apparatus is able to handle numerical data as user data is usually preferably 10 ^{-1 2} or less error rate. Since the optical disk is high, the 10 ^-6 to 10 ^-4 bit error rate as compared with a magnetic disk or magnetic tape, ^10-2 6-10
An error correction method is used to reduce the error of ^-4 to ^10-12 or less.

For this reason, the optical disc employs an error correction code such as a Reed-Solomon code or a BCH code, in which a large number of words are regarded as one block and error correction is performed on a large number of words contained in this block. . In addition, a method called interleaving is used.
Interleaving is a method in which user data is divided into several groups in units of bytes (or bits), error correction codes are generated in units of groups, and then the order is reordered and recorded.

Since interleaving can convert a burst error existing on the disk surface into a random error, it is possible to correct a long burst error by using it together with an error correction code. Interleaving will be described with reference to FIG. An error correction code is added to the data, and the data is arranged vertically in units of words (or bits) as shown in FIG. Then, it is arranged vertically as L rows. At the time of recording, each of L rows (code series) is sequentially recorded from the first row.

In this way, for example, the burst error appearing in the second column in FIG. 2 is 1 in each code sequence.
Are converted into random errors. A write command for one or a plurality of user sectors in the optical disc is input from an external unit (for example, a host computer), and then user data to be written to the optical disc is output from the external unit. The user data is input to the error correction circuit.

The error correction circuit inputs 512By
User data of te (DT0 to DT511 in FIG. 2)
4 vendor unique area (VU0-V
U3) is added. These data are divided into five correction series (code series 0 to 4) together with the 4-byte error detection code (CRC0 to CRC3), and are arranged vertically as five rows as shown in FIG.

The error correction circuit adds an error correction code (EC0, EC0,
0 to EC4,15) are added. Then, the code sequence 0
The data of each row is recorded in the designated sector on the optical disk surface in order from the data of the (first row).
Next, when reproducing the user data from the sector of the optical disc, the data is read from the designated sector on the disc surface and transferred to the error correction circuit. The error correction circuit rearranges the input data again in the order of FIG. 2 (this is called deinterleaving). Then, error correction is performed for each of the five code sequences.

After that, the error detection code is used to check whether or not the corrected user data and vendor unique area have been correctly corrected, and output to the outside.

[0009]

In the conventional technique as described above, a large number of bit errors occur in the read target sector, and even one of the L code sequences has an error of the error correctable byte number or more. If it occurs, the sector cannot be read. Therefore, in the conventional device,
After writing to a sector, it is checked whether the sector is readable (Read After Write Check, hereinafter referred to as RAW check). But this is
Since it is necessary to access and read the written sector again, there is a problem that the write processing time increases and the data transfer rate at the time of writing decreases.

Further, if a subsequent defect occurs after the RAW check and an error of the error correctable number of bytes or more occurs, there is a problem that the generation of the unreadable sector cannot be prevented even if the RAW check is performed. The present invention has been made in view of the above problems, and an object of the present invention is to provide a recording medium and a recording / reproducing apparatus capable of highly reliable recording / reproducing without lowering the transfer rate at the time of data writing. And

[0011]

In order to solve the above problems, the present invention provides a plurality of tracks formed concentrically or spirally on a disk surface, and each track is divided into a plurality of areas. In a disc-type recording medium in which data is written in units of N, the plurality of areas are divided into N groups, and M in the group is divided into groups.
The (N> M) areas are used as user areas for writing user data, and the remaining L (L = N−M) areas are error corrections for the user data written in the M user areas. It is configured to be used as an error correction area for writing a code.

Further, according to the present invention, a plurality of tracks are formed concentrically or spirally on the disk surface, and each track is divided into a plurality of areas, and each area is used as a unit.
In a recording device for recording data on a disc-type recording medium on which data is written, the plurality of areas of the disc-type recording medium are divided into groups of N units, and M (N> A recording device, characterized in that user data is written in M areas, and error correction codes for the user data written in the M areas are written in the remaining L (L = NM) areas.

Further, the reproducing apparatus of the present invention reads the user data from the user sector, and if some of the M user sectors cannot be read due to a large number of bit errors,
The unreadable sector is read by performing error correction on a group basis using the error correction code written in the error correction sector of the group to which the unreadable sector belongs.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is intended for all disc-type storage media and their recording / reproducing devices, but in the present embodiment, a recording / reproducing device using an optical disc which is one of the disc-type recording media (Hereinafter referred to as an optical disk device)
Will be described as an example. FIG. 1 is a diagram showing a configuration of an optical disk device according to an embodiment of the present invention.

In FIG. 1, a plurality of tracks are concentrically or spirally formed on the disk surface of the optical disk 2. Further, each track is divided into a plurality of sectors, and data can be read and written in sector units. Then, in the optical disk device of the present embodiment, these sectors are grouped in units of N, and M sectors of these are read for user data,
The remaining L sectors are allocated to the user sectors used for writing as the sectors for storing error correction codes required for error correction in group units.

First, a case where the optical disk device 1 of FIG. 1 records user data on the disk 2 will be described. In the present embodiment, the number of data bytes in one sector and the error correction method in sector units may be the same as those known in the art, but the invention is not limited to this. An external unit (for example, a host computer) outputs a write command for one or a plurality of user sectors in the optical disc 2, which is input to the input / output circuit 7 in the optical disc device 1. After the output of the write command, the external unit outputs user data to be written to the optical disc 2, and the user data is input to the input / output circuit 7.
The user data input to the input / output circuit 7 is sent to the first error correction circuit 3. The error correction circuit 3 adds a vendor unique area, an error detection code, and an error correction code to all 512-byte user data.

FIG. 2 is a diagram for explaining an example of the error correction method. FIG. 2 shows a 512-byte format of the ISO 90Mmm magneto-optical disk standard. First,
A case where the optical disc device 1 records user data on the disc 2 will be described. Input to the input / output circuit 7,
User data to be written to the disc 2 is 512 By
It is sent to the error correction circuit 3 in units of te (amount of user data written in one sector).

The error correction circuit 3 receives the input 512B
yte user data (DT0 to DT51 in FIG. 2)
In 1), 4 Byte vendor unique area (VU0
~ VU3) is added. These data are divided into five correction series (code series 0 to 4) together with the 4-byte error detection code (CRC0 to CRC3), and are arranged vertically as five rows as shown in FIG.

The error correction circuit 3 adds 16 bytes of error correction code (EC0, EC0,
0 to EC4,15) are added. The data of each line is recorded and reproduced in order from the data of code sequence 0 (first line).
Output to The recording / reproducing circuit 5 records the above data on a specified sector on the surface of the disk 2 via the head 6.

As described above, the user data is divided into several groups in units of bytes (or bits), error correction codes are generated in units of groups, and then the order of recording is rearranged and recorded. It is called interleave. In the above, the error detection code is an error detection code for checking whether or not the user data corrected by the error correction circuit 3 and the vendor unique area can be correctly corrected at the time of data reproduction.
The error detection code is generated from the user data and the vendor unique area, but a conventional method can be used for the generation method, and thus the description thereof is omitted.

The vendor unique area is a 4-byte area in which information that the vendor (manufacturer) wants to record together with user data is recorded. This is also necessary to equalize the number of bytes in the five code sequences. If there is no information that the vendor wants to record along with the user data, a fixed value (such as 00H or FFH) is recorded. The error correction code is generated from user data of each code sequence (and vendor unique area data, error detection code).
A conventional method may be used for the generation method, and thus the description thereof will be omitted.

Next, the user data of the M user sectors of the group including the write target sector and the data of the vendor unique area are input to the second error correction circuit 4, and the error correction code is generated for each group. I do. When reading and writing data in sector units,
It is not necessary to rewrite the data in the user sector that is not the write target in the above group. Therefore, in order to input M group user data and vendor unique area data to the second error correction circuit 4, it is necessary to read the data of the user sector in the group that cannot be rewritten from the optical disc 2 in advance. is there.

However, if data reading and writing are performed only in group units, this is not necessary.
That is, if the dummy data at the time of writing is written to the user sector which is not the write target in the group, it is sufficient to input the predetermined dummy data to the second error correction circuit 4, and the data from the optical disk 2 is input. Does not need to be read.

The second error correction circuit 4 operates as follows. User data DT0 to DT511 and vendor unique areas VU0 to VU3 are extracted one by one from the input data to be written in M sectors, and a total of 516 are extracted.
Code sequences. The length of each code sequence is MByte. Then, for each code sequence, Lby
te error correction codes (GEC1 to GECL) are added. That is, the Lbyte error correction code is 516
Individually created.

The error correction code created in this way is L
It is output as the data of each sector for storing error correction codes. GEC X (X = 1 to L) of each code sequence becomes the data of the Xth error correction code storage sector. Also,
In each error correction code storage sector, the data of the code sequence corresponding to DT0 becomes the first data of the sector, and VU
GECX of each code sequence is arranged so that the data of the code sequence corresponding to 3 becomes the last data.

The created data of the L error correction code storage sectors is input to the first error correction circuit 3. Then, the error detection code and the error correction code are added and input to the error correction circuit 4 again. The write data of the write target sector and the error correction code storage sector created in the error correction circuit 4 as described above is output to the recording / reproducing circuit 5. When writing is performed in group units, write data of all sectors of the group to which the target sector belongs is output to the recording / reproducing circuit 5. Of the sectors in the group, the write data for the non-target sector is dummy data.

The write data input to the recording / reproducing circuit 5 is recorded on a designated sector on the surface of the optical disc 2 via the head 6. After that, the optical disk device 1 does not perform the RAW check and declares the write OK to the external unit. Next, a case where the optical disc device 1 reads user data from the optical disc 2 will be described.

When the input / output circuit 7 of the optical disk device 1 receives a read command for one or a plurality of user sectors in the optical disk 2 from an external unit, the internal recording / reproducing circuit 5 passes through the head 6 and the surface of the optical disk 2 is read. The data of all the sectors of the group to which the target sector of the reading of belongs belongs is read. Then, only the data of the target sector among the read sectors is transferred to the first error correction circuit 3.

In the first error correction circuit 3, the error correction method for performing the error correction of the above-mentioned data has been described in the conventional example, and therefore will be omitted. First error correction circuit 3
If all the target sectors are correct, the user data of the target sector output from the error correction circuit is output to the external unit via the input / output circuit 7, and then the input / output circuit 7 The signal for declaring the correction OK is output to the external unit.

However, if even one of the target sectors has an error correction of NG in the error correction circuit 3, the recording / reproducing circuit 5 makes an error in the data from all the sectors (N) of the group including the NG sector. Send to the correction circuit 4. The error correction circuit 4 performs error correction on a group basis to restore the NG sector. Specifically, the second
The error correction circuit 4 performs the following processing.

From the input N sectors, user data DT0 to DT511, vendor unique area VU0
~ VU3 is extracted one by one to create a total of 516 code sequences. The length of each code sequence is NByte. Error correction is performed on each code sequence. Since the NG sector is known by error correction on a sector-by-sector basis, if this information is input to the error correction circuit 4, it is possible to know in advance which number byte of the code sequence is in error. Therefore, it is possible to perform erasure correction.

The restored user data of the NG sector and the data of the vendor unique area are output to the input / output circuit 7. The input / output circuit 7 outputs the user data of all target sectors to the external unit, and then declares the correction OK to the external unit.

[0033]

As described above, in the disk type recording medium and the recording / reproducing apparatus thereof of the present invention, when several target sectors are unreadable due to a large number of bit errors, the error correction of the group to which the unreadable sectors belong is corrected. By using the error correction code written in the dedicated sector to perform error correction in group units, the unreadable sector is read, so there is no need to perform the RAW check, which was conventionally performed when writing data. The effect is that the transfer rate can be improved.

Further, the unreadable sector due to the bit error generated after the write could not be prevented by the RAW check, but due to the error correction in the group unit,
There is also an effect that it can be read and made possible.

[Brief description of drawings]

FIG. 1 is a block diagram of an optical disc device according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a conventional error correction method.

[Explanation of symbols]

 1 ... optical disk device, 2 ... disk, 3 ... first error correction circuit, 4 ... second error correction circuit, 5 ... recording / reproducing circuit, 6 ... head 7 ... input / output circuit

Claims (3)

[Claims] 1. A disc-type recording medium in which a plurality of tracks are formed concentrically or spirally on a disc surface, and each track is divided into a plurality of regions, and data is written in units of the regions. , The plurality of areas are grouped in units of N, and M (N> M) areas in the group are used as user areas for writing user data, and the remaining L (L = N−M) areas are used. The area is used as an error correction area for writing an error correction code for the user data written in the M user areas. 2. A disk-type recording medium in which a plurality of tracks are formed concentrically or spirally on a disk surface, each track is divided into a plurality of areas, and data is written in units of the areas. In a recording device for recording data, the plurality of areas of the disk-type recording medium are divided into N groups, and user data is written in M (N> M) areas in the group, and the remaining areas are recorded. A recording apparatus, wherein the error correction code for the user data written in the M areas is written in the L (L = NM) areas. 3. A reproducing apparatus for reproducing the data recorded on the disc type recording medium according to claim 1, wherein the user data is read from the user sector, and several bits out of M user sectors have a large number of bits. When the unreadable sector cannot be read due to an error, the unreadable sector is read by performing error correction in group units using the error correction code written in the error correction sector of the group to which the unreadable sector belongs. A playback device characterized by the above.