JPH0555928A - Method and device for error correction - Google Patents

Abstract

PURPOSE:To simplify the management of data by storing continuously the data in an excellent way even when a medium implementing error correction by the CIRC is used for an external storage means in a computer or the like. CONSTITUTION:The error correction processing for data fed from a computer 22 is implemented by a CIRC encoder circuit 18, and written on a disk by a pickup 10. At the end of processing, the content of a register and a data buffer in the CIRC encoder circuit.18 is stored tentatively based on a command by a control circuit 20. Then at the restart of processing, the stored data is read and the CIRC encoder circuit 18 is restored to the state at the end of processing. Then a coefficient extract/recalculation circuit 24 calculates the error correction code with respect to a succeeding data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an error correction method and apparatus for a CD (Compact Disc) and the like, and in particular, an error correction code added to a series of blocks of data is added after the block. CIRC (Closs Interleasure) that has some correlation with consecutive blocks
The present invention relates to an error correction method and apparatus suitable for performing error correction using an error correction code such as ve Reed Solomon Code).

[0002]

2. Description of the Related Art In the audio field, CDs and the like have rapidly become popular in place of records and tapes. Further, in computer systems, the use as a read-only external recording medium such as a CD-ROM is becoming widespread.
Write-on types, such as -MO (rewritable memory) and CD-WO (write-once type memory), which can be expected to have the same reproduction characteristics as CD in terms of signal level and medium characteristics, have also been developed.

In such a CD or CD-ROM,
CIRC against signal loss due to scratches on media
Error correction by a strong code called
This provides strong error correction and provides high quality sources.

Regarding this CIRC, for example, "New Edition Digital Audio" issued by Radio Engineering Co., Ltd., Toshida Doi,
It is described in detail in Akira Iga, P183 to P233, etc.
Further, Japanese Patent Application Laid-Open No. 61-242425 discloses an example of a composite method for erasure correction of Reed-Solomon code, and Japanese Patent Application No. 3-119575 discloses an example of a demodulation circuit.

By the way, in CIRC and the like, an error correction code added to a series of block data has a correlation with a block succeeding the block. Therefore, the error correction code cannot be generated using only the data of a certain block. For example, in FIG.
As shown in (B), the error correction code C1 for the frame 1 is not limited to the data F1 of the frame 1 but also the frame 1
Data of frames 2 and 3 following F2, F3
Is also generated by referring to. Similarly, the error correction code C2 for the frame 2 is generated by referring to the data F3 and F4 of the frame 3 and the frame 4 in addition to the frame 2.
The same applies hereinafter.

Therefore, CD, CD-ROM, CD-M
In O and CD-WO, an error correction code is obtained in advance for the data to be recorded, and all the data including them or the data having a certain size are continuously written at once. Alternatively, an invalid area is provided at the connection point for data writing so that the write data is not lost during reproduction (for example, CD-W).
See O specifications).

[0007]

However, in a computer or the like, the data to be written is not determined in advance for all areas of the storage medium, and temporary storage of data may be performed during the processing as needed. Be seen. Therefore, C is used as an external storage medium of the computer.
When using D-WO or the like, there is a disadvantage that information management becomes very complicated.

The present invention focuses on this point, and an error correction method capable of favorably storing data even when a medium for performing error correction by CIRC or the like is used as an external storage means in a computer or the like. The purpose is to provide such a device.

[0009]

SUMMARY OF THE INVENTION The present invention is directed to an error correction method and apparatus using an error correction code in which a code added to a certain block of data has a correlation with a block succeeding the block. In the above, at the time when a series of data writing to the storage medium ends, the data of the last few blocks of the data to be written and the internal state of the correction means at that time are temporarily stored in the data storage means, and they are stored when the processing is restarted. It is characterized in that error correction processing for subsequent blocks is continuously performed by recalculation means using data.

[0010]

According to the present invention, at the end of processing in a computer or the like, data required for error correction processing at restart is temporarily stored. For example, data of a plurality of blocks at the ends of which the error correction code has a correlation is stored. Then, when the processing is restarted, the stored data is read and used for recalculation of the error correction code after the restart.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the error correction method and apparatus according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows the configuration of this embodiment. In the figure, a pickup 10 for writing and reading data to and from a disc (not shown) is connected to an input side of an analog receiver circuit 12 and an output side of an analog driver circuit 14, respectively. The output side of the analog receiver circuit 12 is connected to the input side of the CIRC decoder circuit 16, and the input side of the analog driver circuit 14 is connected to the CIRC.
It is connected to the output side of the encoder circuit 18.

Next, the output side of the CIRC decoder circuit 16 and the input side of the CIRC encoder circuit 18 are both connected to a control circuit 20, which is
On the other hand, it is connected to the computer 22. The other output side of the CIRC encoder circuit 18 is connected to the input side of the coefficient extraction / recalculation circuit 24, and the output side of the coefficient extraction / recalculation circuit 24 is connected to the other input side of the analog driver circuit 14. It is connected. Further, the other output side of the control circuit 20 is connected to the input side of the optical control system 26 for the pickup 10.

Of the above parts, the pickup 10 is
It is for writing or reading data to or from a predetermined track on the disk by being driven by the optical control system 24 based on an instruction from the control circuit 20. The analog receiver circuit 12 is for receiving the data read by the pickup 10 and outputting it to the CRIC decoder circuit 16. Analog driver circuit 14
Is for supplying data to be written to the pickup 10.

Next, the CIRC decoder circuit 16 is for performing error correction decoding by CIRC on the input data. The CIRC encoder circuit 18 performs error correction encoding by CIRC on the data supplied from the computer 22. At this time, a memory (not shown) or a memory 18A acting as a data buffer is used. The control circuit 20 has a function of controlling transmission / reception of data between the computer 22 and the disc, and performing a recalculation of an error correction code described later and a process control of temporary storage of data.

Next, the coefficient extraction / recalculation circuit 24 uses the CI
This is for extracting the coefficient of the data to be encoded input to the RC encoder circuit 18 and recalculating the error correction code based on the CIRC of the corresponding data frame.

Next, regarding the overall operation of the above embodiment,
This will be described with reference to FIGS. 2 and 3. Computer 2
2 outputs data D1, D2, D3, ..., Dn, ... To be stored in the disk to the control circuit 20 at any time according to the processing status. The control circuit 20 sends the data D1, D2, ...
Output to the RC encoder circuit 18.

First, the first data D1 is the computer 2
It is assumed that the data is input to the control circuit 20 from 2. This data D
1 is supplied from the control circuit 20 to the CIRC encoder circuit 18. In the CIRC encoder circuit 18, the input data D1 is stored in the memory 18A. Figure 2
This state is shown in (A). Similarly, the data D2 and D3 output from the computer 22 are sequentially stored in the memory 18A (see FIG. 7B).

At this point, the CIRC encoder circuit 18 scrambles the data D1, D2, D3 to obtain frames F1, F2, F3, respectively, and the coefficient extraction / recalculation circuit 24 extracts the coefficient and the error correction code. Recalculation of C1 is performed (see FIG. 3B).
Then, the frame F1 and its error correction code C1 are output to the pickup 10 via the analog driver circuit 14.

The optical control system 26 is controlled and driven so that the writing of data by the pickup 10 is started from a predetermined position on the disk 30 based on an instruction from the control circuit 20. As a result, for example, as shown in FIG. 2C, the frame F1 and the error correction code C1 are written at a predetermined position on the disk 30.

When the data D4 is output from the computer 22 to the control circuit 20, the memory 18 for the data D4 is stored.
The storage in A, the recalculation of the error correction code C2 for the frame F2, and the writing of F2 and C2 in the disk 30 are performed in the same manner as described above (see FIG. 2D).

The above operation is repeated every time data is output from the computer 22. As a result, the disk 30 has F1, C1, F2, C2, ..., Fn, Cn
Are continuously written (see (E) in the figure). In this state, the data Dn, Dn + 1, Dn + 2
Are stored in the memory 18A.

At this point, assuming that the processing in the computer 22 is completed, the data Dn + 1, Dn stored in the memory 18A based on the instruction from the control circuit 20.
The data EN in +2 and the register of the CIRC encoder circuit 18 is output to the pickup 10 via the analog driver circuit 14.

At the same time, the operation of the optical control system 26 based on the instruction of the control circuit 20 moves the pickup 10 to the temporary storage position of the disk 30. As a result, the data Dn + 1, Dn + 2, E are stored in the temporary storage position of the disk 30.
N will be recorded respectively. When the power is cut off
The data in the memory 18A disappears (see (F) in the figure).

Next, when the processing in the computer 22 is restarted and the disk 30 of FIG. 2 (F) is set in the apparatus of FIG. 1, the data is operated by the operation of the optical control system 26 based on the instruction of the control circuit 20. Dn + 1, Dn + 2, EN
Are read from the disk 30. These data Dn
+1, Dn + 2, and EN are the CIRC encoder circuit 18 from the optical pickup 10 via the analog driver circuit 12, the CIRC decoder circuit 16, and the control circuit 20, respectively.
Is supplied to. Then, the data Dn + 1 and Dn + 2 are stored in the memory 18A, and the data EN is stored in the register of the CIRC encoder circuit 18.

By this operation, the CIRC encoder circuit 18 returns to the state before the processing is completed, that is, the state shown in FIG. 2 (E). That is, when the next data arrives, the frame Fn + 1 and its error correction code Cn +
1 becomes a state in which calculation is possible. Then, the next data Dn +
3 is supplied from the computer 22, the frame Fn + 1 and its error correction code Cn + 1 are transmitted as described above.
Is obtained, and the data is continuously written on the disc 30. The operation shown in FIG. 2 is repeatedly executed as needed.

As described above, according to the present embodiment, when the data writing to the disk is completed due to the completion of the processing by the computer, the internal information such as the last two frames and the contents of the register in the CIRC encoder circuit 18 is other than the disk. Is recorded in the part of and is temporarily saved. Then, at the time of data writing accompanying the start of the next processing, the recorded last two frames and the internal information in the CIRC encoder circuit 18 are read out, and after the processing is restarted, the data transferred from the computer is added and the error correction code is recalculated. It Therefore, the EFM signal is written on the disc while maintaining phase continuity. Therefore, the error correction code is calculated in advance for the whole and the same as in the conventional case where the error correction code is written on the disk, and the correction code is normally reproduced.

As a result, it becomes possible to write the data to which the error correction code based on the CIRC is added to the disc at any time according to the processing situation in the computer. That is, it becomes possible to use the CD like a magnetic storage medium such as an FD.

The present invention is not limited to the above embodiment, and includes, for example, the following. (1) In the above embodiment, CIRC is used as an error correction method.
However, the present invention is widely applicable to cases where a code added to a fixed block of a series of data has a correlation with a block succeeding the block, and these cases are also included in the present invention. Be done. Even if CIRC is used, the number of subsequent frames to be considered, the scrambling method, and the like may be appropriately changed as necessary.

(2) In the above embodiment, the contents of the registers and the data buffers in the CIRC encoder circuit are temporarily stored using the disk. However, a memory means may be prepared separately. This is convenient in the case of CD-WO. Further, although a CD-MO or the like is suitable as a storage medium to be applied, it does not prevent application to other media. (3) Further, the circuit configuration can be variously modified so as to achieve the same operation, for example, software implementation using a microcomputer.

[0030]

As described above, according to the error correction method and apparatus according to the present invention, the required data at the end of the data to be written and the internal state of the correction means at that time are temporarily stored at the end of the processing. Therefore, there is an effect that it is possible to perform error correction satisfactorily by using the stored data at the time of restarting the processing and perform continuous data recording.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of an error correction device according to the present invention.

FIG. 2 is an explanatory diagram showing a specific example of an error correction method according to the present invention.

FIG. 3 is an explanatory diagram showing a data string of a main part in FIG.

[Explanation of symbols]

10 ... Pickup, 12 ... Analog receiver circuit, 1
4 ... Analog driver circuit, 16 ... CIRC decoder circuit, 18 ... CIRC encoder circuit (correction means), 18
A ... Memory, 20 ... Control circuit, 22 ... Computer, 2
4 ... Coefficient extraction / recalculation circuit (recalculation means), 26 ... Optical control system, 30 ... Disk (storage medium, data storage means).

Claims (2)

[Claims] 1. An error correction method using an error correction code in which a code added to a certain block of data has a correlation with a block succeeding the block, and a series of data writing to a storage medium is completed. At the time of doing, temporarily save the data of the last few blocks of the data to be written and the internal state of the correction means at that time,
An error correction method characterized in that, when the processing is restarted, the error correction processing is continuously performed on subsequent blocks using the saved data. 2. In an error correction device using an error correction code in which a code added to a certain block of data has a correlation with a block following the block, a series of data writing to a storage medium is completed. At the point of time, the data of the last few blocks of the data to be written and the data storing means for temporarily storing the internal state of the correcting means at that time, and the data stored in the data storing means at the time of resuming the processing are read and followed. An error correction device comprising: a recalculation unit that recalculates an error correction code for a block.