JP2004103235A - Recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording and reproducing method in which access for a small size sector securing reliability of data and access speed is improved. <P>SOLUTION: A header in which an address signal is recorded is provided for each prescribed sector interval in a disk. Recording data is arranged in an error correction encoding block, and error correction encoding processing is performed. This error correction encoding block is divided into a plurality of pieces in the prescribed direction and S1, S2, S3, ... are formed. Succeeding to the header, data for each sector is recorded. At the time of reproduction, the header is detected and data is reproduced for each sector. One direction of error correction processing is performed by reproduced data in the sector S1, S2, S3, ... , when error correction processing cannot be performed by reproduced data in this sector, the error correction block including the sector S1, S2, S3, ... is reproduced, error correction processing is performed by systems of two directions. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention particularly relates to a recording medium suitable for recording data for a computer on an optical disk such as a DVD.

DVD (Digital Video Disk) has been developed as a storage medium for recording digital video signals compressed by MPEG or the like. A DVD is an optical disk having the same diameter as a CD (compact disk). The recording density is increased by progress in shortening the wavelength of laser light, and by improving digital modulation and error correction encoding processing with an increase in the NA of an objective lens. It has been further improved. DVDs have a huge data storage capacity of about 3.7 Gbytes even in the case of a single-layer disc. As a form of DVD, there has been proposed a DVD that can be recorded / reproduced by using an MO disk or a phase-change optical disk in addition to a read-only optical disk.

用 い る It has been proposed to use such a DVD as an external storage device of a computer. In other words, an optical disk drive has attracted attention as an external storage device of a computer because of its advantages of large capacity and high-speed access. MD data or the like for recording / reproducing data on / from a disc has been proposed. DVD has a huge data storage capacity of about 3.7 Gbytes, and is therefore expected as an external storage medium capable of storing a larger amount of data.

@DVDs have been subjected to error correction encoding to protect recorded data. In DVDs, convolutional cross-interleave codes are used because they handle sequential data such as video data. However, the use of convolutional codes makes it difficult to access data in sector units and to read / write data. When used as an external storage medium for recording / reproducing computer data, it is necessary to access data in sector units to read / write data, and therefore, it is necessary to use block-complete codes.

FIG. 9 shows an example of a process for generating a convolutional cross-interleave code. As shown in FIG. 9, in the C1 sequence, a parity P of, for example, 8 bytes is added to, for example, 162 bytes in the vertical direction, and in the C2 sequence, a parity Q of, for example, 14 bytes is added in the diagonal direction. From the 148 bytes of data in the vertical direction, the parity P of 8 bytes, and the parity Q of 14 bytes, the number of data in the vertical direction is 170 bytes. Data recorded on the disk is read out in synchronization with a frame, and one frame is 85 bytes. The 170-byte data in the vertical direction corresponds to exactly two frames.

As described above, convolutional cross-interleave codes are used in DVDs, but with convolutional codes, it is difficult to access data for each block and read / write data. Therefore, it is conceivable to use a block-completed cross-interleave code.

FIG. 10 shows an example of processing when a block-completed cross-interleave code is generated. In order to achieve commonality with the above-described convolutional code, the number of data in the vertical direction is 148 bytes, the parity P is 8 bytes, the parity Q is 14 bytes, and the total number of data in the vertical direction is 170 bytes. Since one sector is, for example, 16 kbytes, the number of data in the horizontal direction is 112 bytes (148 × 112 = 16576 bytes). If a block-completed cross-interleave code is used, the interleave length is longer than the block width. For this reason, as shown in FIG. 10, when the length reaches 112 bytes, the C2 sequence is folded. As shown in FIG. 10, when a block-completed cross-interleave code is used, data can be read / written for each block and used as an external storage medium for recording / reproducing data for a computer. It is suitable for the case.

By the way, the larger the sector size when recording / reproducing data on a data recording medium such as a DVD, the higher the density and the higher the reliability. At the same time, the size of files to be handled has been increasing. For this reason, in recent years, the sector size of the data recording medium has tended to increase, and the size of one sector has shifted from the initial 512 bytes to 1024 bytes and 2 kbytes.

However, access to the recording medium is performed in sector units. For this reason, when the sector size is large, there is a problem that the recording / reproducing time is long and the access speed is reduced. In addition, there is a demand to be able to handle small sectors due to the problem of compatibility with sectors of existing data recording media.

However, when data is recorded on a DVD, there is a problem that if the number of sectors is reduced, the reliability of the data is reduced.

In other words, in the above example, the sector size is set to 16 kbytes. When the sector size is set to 16 kbytes, as shown in FIG. 10, one turn of the C2 sequence occurs.

ブ ロ ッ ク Because the block shown in FIG. 10 is 16 kbytes, if it is divided into eight, a 2 kbyte sector can be constituted. However, as shown in FIG. 11, when a 16-kbyte block is divided into eight to form a 2-kbyte (14.times.148 = 2072 bytes) sector and error correction coding is performed using a cross-interleave code in the same manner as described above. , C2 series have many folds. For this reason, sufficient error correction cannot be performed.

As described above, increasing the sector size has the advantage of improving data reliability, but has the disadvantage of slowing down the access speed. On the other hand, when the sector size is reduced, there is an advantage that the access speed is increased, but there is a disadvantage that data reliability is reduced.

Accordingly, it is an object of the present invention to provide a recording medium capable of accessing a small-sized sector and improving the access speed while ensuring data reliability.

In order to achieve the above object, the invention according to claim 1 provides an error correction code in a vertical direction and a horizontal direction by arranging in an error correction coding block on a recording medium in which an address signal for each sector is recorded in advance. The data that has been subjected to the conversion processing is divided into a plurality of sectors having the same size, including at least a part of the error correction code in two directions in the vertical direction or the horizontal direction, and a sector is formed. It is a recording medium recorded correspondingly.

ヘ ッ ダ A header is recorded on the disk at predetermined sector intervals. The header includes an address signal. The recording data is arranged in an error correction coding block, and error correction coding processing is performed. The error correction coding block is divided into a plurality of blocks in a predetermined direction to form a sector. Following the header, data for each sector is recorded. Since the sector is formed by dividing the error correction coding block into a plurality of parts in a predetermined direction, when error correction coding is performed in two directions by the error correction coding block, one error correction process is performed in each sector. I can do it. At the time of reproduction, this header is detected and data is reproduced for each sector. One error correction process is performed on the reproduced data in the sector. If the reproduced data in this sector cannot be corrected by the error correction processing, an error correction block including that sector is reproduced. Then, error correction processing is performed in a two-way sequence. In this way, a small-sized sector can be handled without deteriorating data reliability.

According to the present invention, the error correction coding block is divided into a plurality of blocks in a predetermined direction to form a sector, and data of each sector is recorded following a header including an address signal. Since the sector is formed by dividing the error correction coding block into a plurality of parts in a predetermined direction, the error correction coding block can perform error correction processing in one direction in each sector. At the time of reproduction, this header is detected, data is reproduced for each sector, and error correction processing is performed in one direction with the reproduction data in the sector. The correction block is reproduced, and error correction processing is performed in two directions. Therefore, a small-sized sector can be handled, the access speed can be improved, and the reliability of data does not deteriorate.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an example of a data recording / reproducing apparatus to which the present invention can be applied. In this example, a block for error correction coding is, for example, 16 kbytes, and a sector size is, for example, 2 kbytes. Data can be handled for each 2 kbyte sector.

に お い て In FIG. 1, reference numeral 1 denotes an optical disk. The optical disk 1 is rotated by a spindle motor 2. In this example, the optical disk 1 is a magneto-optical disk, which is basically composed of a DVD for recording digital video signals, and has a data storage capacity of about 3.7 Gbytes. The optical disc 1 may be of a phase change type. Data is recorded / reproduced on the optical disc 1 for each sector.

光学 The optical pickup 3 and the magnetic head 4 are provided for the optical disk 1. Although not shown, the optical pickup 3 and the magnetic head 4 can be integrally moved in the radial direction of the disk by a thread feed mechanism.

# 5 is an interface. As the interface 5, for example, SCSI is used. Data and commands are exchanged with the host computer 6 via the interface 5.

When recording data on the optical disk 1, data is input from the interface 5. This data is supplied to the blocking circuit 7. The blocking circuit 7 blocks recording data in order to perform block-corrected error correction coding.

The error correction encoding circuit 8 performs an error correction encoding process using a block-completed error correction code. The error correction encoding circuit 8 performs an error correction encoding process for each block.

ブ ロ ッ ク As described later, a block for error correction coding is divided into a plurality of blocks and handled. The division results in a sector. That is, one block includes a plurality of sectors. The optical disc 1 is provided with a header including an address signal by, for example, pre-pits. Data of each sector is recorded following the header including the address signal.

The output of the error correction encoding circuit 8 is supplied to the modulation circuit 9. The recording data is modulated by the modulation circuit 9. The output of the modulation circuit 9 is supplied to the magnetic head 4 via the driver 10. The optical disk 1 is applied with a magnetic field modulated by data from a magnetic head 4 and is irradiated with a laser beam from an optical pickup 3. Thereby, data is recorded on the optical disc 1.

As described above, in this example, data is recorded in a magnetic field modulation system in which a magnetic field modulated with data is applied to the magnetic head 4 and a laser beam is emitted from the optical pickup 3 at the time of data writing. Is not specified in the magnetic field modulation method.

At the time of reproduction, a reproduction signal of the optical disk 1 is obtained from the optical pickup 3. This reproduced signal is supplied to the RF amplifier 11. The reproduction signal from the RF amplifier 11 is supplied to the demodulation circuit 12. In the demodulation circuit 12, the data is demodulated. The output of the demodulation circuit 12 is supplied to the error correction decoding circuit 13.

As described above, the optical disk 1 records the header including the address signal. With this header, a desired sector can be accessed to reproduce data. The error correction decoding circuit 13 performs an error correction process on the sector using the C1 sequence. If the error correction cannot be performed using only the C1 sequence, all the error correction blocks including the sector are reproduced, and the error is corrected using the C1 sequence and the C2 sequence. Correction processing is performed.

出力 The output of the error correction decoding circuit 13 is supplied to the block decomposition circuit 14. The block decomposition circuit 14 performs a process corresponding to the above-described blocking circuit 7. The output of the block decomposition circuit 14 is sent to the interface 5, and data is output to the outside via the interface 5.

(4) The RF amplifier 11 outputs a tracking error signal and a focus error signal. These tracking error signal and focus error signal are supplied to the servo circuit 15. The servo circuit 15 generates a tracking control signal, a focus control signal, a sled motor control signal, a laser power control signal, a spindle motor control signal, and the like under the management of the system controller 16. The tracking control signal, the focus control signal, and the control signal of the sled motor are supplied to the optical pickup 3, whereby the tracking servo control and the focus servo control are performed. Further, a control signal of the laser power is supplied to the optical pickup 3, and the optimum laser power is set according to the time of recording / reproduction. Further, a control signal of the spindle motor is supplied to the spindle motor 2 via the driver 17 to control the rotation of the optical disk.

In one embodiment of the present invention, as described above, the block for error correction coding is composed of a plurality of sectors. The block for error correction encoding is, for example, 16 kbytes, and the sector is 2 kbytes.

FIG. 2 shows an example of a block for error correction encoding. As shown in FIG. 2, 148 bytes of data are arranged in the vertical direction and 112 bytes of data are arranged in the horizontal direction. An 8-byte parity P is added to the vertical C1 sequence, and a 14-byte parity Q is added to the diagonal C2 sequence. A block composed of 170 bytes (data of 148 bytes, parity P of 8 bytes, and parity Q of 14 bytes) in the vertical direction and 112 bytes in the horizontal direction configured as described above is used for error correction encoding. Blocked. The (170,162,9) Reed-Solomon code is used in the C1 sequence, and the (170,156,15) Reed-Solomon code is used in the C2 sequence. Data is read / written in the vertical direction.

構造 The structure of this block is basically the same as the structure of the block-completed cross interleave code shown in FIG. However, normally, zigzag interleaving is performed in the vertical direction, but such zigzag interleaving is not performed so that the error correction code is completed for each sector.

As shown in FIG. 3, one block obtained by dividing one block for error correction encoding into eight is defined as sectors S1, S2, S3,... S8. That is, each of the sectors S1 to S8 is composed of 14 bytes in the horizontal direction and 148 bytes in the vertical direction, and the data capacity of one sector is as follows.
148 × 14 = 2072 bytes, and including parity P and Q,
170 × 14 = 2380 bytes.

FIG. 4 shows the configuration of each of the sectors S1 to S8. Each sector is composed of a header section and a data section as shown in FIG. 4A. As shown in FIG. 4B, the header portion includes a 6-byte sector mark (SM) used for sector detection, a 24-byte VFO1 and a 15-byte VFO2 used for pulling in a PLL, and a 2-byte address mark ( AM) and a 5-byte address (ID1, ID2). The address includes a track address, a sector address, and an error detection code CRC. This sector portion is formed, for example, by pre-pits.

As shown in FIG. 4A, the data section is composed of 20 bytes of VFO3 used for PLL loading, 2380 bytes of data and an error correction code. Further, a buffer, a gap (Gap), etc. for absorbing post ampoule (PA), spindle motor detter, disk eccentricity and the like are included. Also, a sync (sector sync, frame sync) for synchronizing data is added. Of the 2380-byte data, 2072 bytes are user data, and the user data can include a CRC code for error detection, thereby protecting the data.

セ ク タ Thus, each sector is provided with a header section at the beginning. At the time of reproduction, data is accessed for each sector using this header section. For data of one sector, error correction processing can be performed in the C1 sequence using the parity P. Error correction is performed in the C1 sequence, and if correction is not possible only with the C1 sequence, all error correction blocks including the sector are reproduced, and error correction processing is performed using the C1 sequence and the C2 sequence.

That is, as shown in FIG. 5, when there is a sector reproduction request (step ST1), first, a desired sector is accessed and the data of this sector is reproduced (step ST2). An error correction decoding process is performed on the C1 sequence using the parity P (step ST3). It is determined whether error correction is possible in the C1 sequence (step ST4). If correction is possible, reproduction of the sector is completed. If there is an uncorrectable error, all error correction blocks including the sector are accessed, and one block of data is reproduced (step ST5). Then, a decoding process is performed using the C1 sequence and the C2 sequence (step ST6).

As described above, in this embodiment, it is possible to reproduce data in units of 2 kbytes, even though the error correction coding block is 16 kbytes. At the time of reproduction, it is only necessary to access a small-sized sector (2 kbytes) without accessing one block (16 kbytes), so that the data access speed can be increased. When an error that cannot be corrected by the C1 sequence alone occurs, the error correction process can be performed using the C1 sequence and the C2 sequence using the error correction coding block, and the data reliability is lost. I can't.

FIG. 6 shows another embodiment of the present invention. In the above embodiment, a cross interleave code is used, but in this embodiment, a product code is used.

(6) As shown in FIG. 6, data of 83 bytes in the vertical direction and 200 bytes in the horizontal direction are arranged. Then, a 2-byte parity P is added to the vertical C1 sequence, and a 25-byte parity Q is added to the horizontal C2 sequence. As described above, 85 bytes in the vertical direction (83 bytes of data and 2 bytes of parity P) and 225 bytes in the horizontal direction (200 bytes of data and 25 bytes of parity Q) are used for error correction encoding. A block is configured. A (85,83,3) Reed-Solomon code is used in the C1 sequence, and a (225,200,26) Reed-Solomon code is used in the C2 sequence.

As shown in FIG. 7, one block for error correction encoding is divided into nine, and the divided ones are defined as sectors S11, S12, S13,... S19. The horizontal length of the block for error correction encoding is 225 bytes, and this is divided into nine to form a sector. Therefore, the horizontal length of one sector is 25 bytes. In the C2 sequence, a parity Q of 25 bytes is added. Therefore, among these sectors S11 to S19, the sector S19 is a sector having only parity. This sector is hereinafter referred to as a parity sector.

The data capacity of each of the sectors S11 to S18 other than the parity sector S19 is as follows.
83 × 25 = 2075 bytes, including parity P,
85 × 25 = 2125 bytes. Data is read / written in the vertical direction. The parity sectors S19 are all parity P and Q, and their size is equal to the sectors S11 to S18.

(4) The data of each sector is arranged following the header in which the address is recorded, as in the above-described embodiment. The configuration of the header section can be the same as that shown in FIG.

During playback, data is accessed for each of the sectors S11, S12, S13,... Using the header section. For data of one sector, error correction processing can be performed using parity P in the C1 sequence. The error correction process is performed only on the C1 sequence, and if the correction is impossible only on the C1 sequence, all the error correction blocks including the sector are reproduced, and the error correction process is performed using the C1 sequence and the C2 sequence.

で は In this embodiment, a parity sector S19 is provided. For this reason, when data is rewritten for each sector, it can be dealt with only by rewriting the parity sector S19, and the data can be easily rewritten for each sector.

In other words, when data is rewritten for each sector, a process as shown in FIG. 8 is performed. When there is a data rewrite request for a sector (step ST11), first, the sector for which data is to be rewritten is accessed and this data is read (step ST12). Data to be newly recorded this time is input (step ST13), and a difference between the current data and the data before rewriting is obtained (step ST14). This difference data is temporarily stored in order to rewrite the data of the parity sector (step ST15). From this data, the parity P of the C1 sequence of the sector is obtained (step ST16). The current data and parity P are recorded in the sector (step ST17).

(4) When new data is written in the sector, the parity sector is accessed (step ST18). The difference data between the current data stored in step ST14 and the data before rewriting is added to the data of the parity sector. Thus, a new parity Q is obtained by adding the difference data between the current data and the data before rewriting to the data of the parity sector (step ST19). The parity sector is rewritten by the parity Q thus obtained (step ST20).

As described above, when rewriting a desired sector, it is only necessary to add the difference data between the current data and the data before rewriting to the data of the parity sector to obtain a parity Q, and rewrite the parity sector using the parity Q. . Therefore, it is not necessary to reproduce all the data of the coded block and recalculate the parity.

In this manner, when a parity sector is provided and a desired sector is rewritten, the parity sector is rewritten by adding the difference data between the current data and the data before rewriting to the parity sector data to obtain a parity Q. The configuration to be performed is not limited to the configuration using the product code. For example, the present invention can be similarly applied to a case where a cross interleave code is used. For example, in the case of the configuration shown in FIG. 3, it is conceivable that the parity Q is arranged in the sector S8 and the sector S8 is a parity sector.

In the above-described embodiment, the header section in which the address is recorded is provided, and this header section is, for example, a pre-pit. However, the address may be wobble-recorded along the groove of the track. good.

The present invention is not limited to the above-described embodiment of the present invention, and various modifications and applications are possible without departing from the gist of the present invention.

1 is a block diagram of an example of a recording / reproducing device to which the present invention can be applied. FIG. 2 is a schematic diagram used for describing one embodiment of the present invention. FIG. 2 is a schematic diagram used for describing one embodiment of the present invention. FIG. 3 is a schematic diagram used for describing a configuration of a header in one embodiment of the present invention. 5 is a flowchart used to explain one embodiment of the present invention. FIG. 10 is a schematic diagram used for describing another embodiment of the present invention. FIG. 10 is a schematic diagram used for describing another embodiment of the present invention. 9 is a flowchart used to explain another embodiment of the present invention. FIG. 9 is a schematic diagram used for explaining a conventional data recording method. FIG. 9 is a schematic diagram used for explaining a conventional data recording method. FIG. 9 is a schematic diagram used for explaining a conventional data recording method.

Explanation of reference numerals

Reference Signs List 1 optical disk 8 error correction encoding circuit 13 error correction decoding circuit

Claims (1)

In a recording medium in which an address signal for each sector is recorded in advance,
The data arranged in the error correction coding block and subjected to the error correction coding processing in two directions of the vertical direction and the horizontal direction is converted into at least a part of the error correction codes in the two directions in the vertical direction or the horizontal direction. A recording medium which includes and is divided into a plurality of pieces having the same size to form a sector and recorded in accordance with the address signal.

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