JP2615564B2 - Data recording method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in the following order.

A. Industrial application fields B. Summary of the invention C. Conventional technology D. Problems to be solved by the invention E. Means to solve the problems F. Function G. Example G-1.1 sectors Data structure (FIG. 1) G-2. Recording format (FIG. 2) G-3. Magneto-optical disk drive (FIG. 3) G-4. Other embodiments (FIGS. 4 and 5) A. Field of the Invention The present invention relates to a data recording method for recording data on a recording medium such as a magneto-optical disk, and more particularly, to a disk-shaped disk on which a servo signal and a data signal are alternately recorded along a track. The present invention relates to a method for sequentially recording two-dimensional array data such as a so-called product code in a data signal area of a recording medium.

B. Summary of the Invention The present invention sequentially records data signals in each data signal area on a recording medium in which servo signal areas and data signal areas are alternately provided along a scanning direction during signal recording and reproduction. In a data signal recording method, data to be recorded is formed into a two-dimensional array and an error detection / correction code is added to form a so-called product code. By setting the length to an integral multiple of the length, the adverse effect due to the occurrence of an error is suppressed and the error correction capability is improved.

C. Prior Art In recent years, optical recording media such as optical disks and magneto-optical disks utilizing an optical or magneto-optical signal recording / reproducing method have been developed and are being supplied to the market. These optical recording media include digital audio discs such as so-called CDs (compact discs) and video discs.
Similar to a disk, a so-called ROM (read only memory) type recording medium for recording various information signals in advance on a recording medium by a manufacturer in a non-rewritable manner and supplying it to a user, and a so-called DRAW or write-once type A so-called PROM that allows the user to write information signals only once.
There are a (programmable ROM) type recording medium and a so-called RAM (random access memory) type recording medium capable of erasing and rewriting recorded information signals, such as a magneto-optical disk. Is very large.

Each of these types of optical recording media is often used in the form of a disc, but has been developed individually and has different development periods, so that different formats are used. For this reason, compatibility between these types of discs cannot be obtained, and there are many disadvantages on both the user side and the maker side. Here, as one of the technologies for realizing this unified format,
Similar to the so-called sector servo in the field of magnetic disks, servo signals are recorded at predetermined intervals or at predetermined angles on concentric or spiral tracks on the disk. It has been proposed to introduce a so-called sampling servo concept that performs continuous servo control by sampling and holding a discrete servo signal. The data signal is sequentially recorded between the servo signals, and the recording area of the servo signal and the data signal recording area are alternately arranged along the track direction which is the scanning direction of the pickup head or the like. Will be placed.

In this case, the number of servo signals for one rotation of the unified format disk is limited to some extent according to conditions such as disk rotation speed and servo control characteristics. It is necessary to record and form about servo signals.

By the way, the recording capacity of such an optical disk or the like is extremely large, for example, about several hundred Mbytes or more, and it is important to take measures against errors such as burst errors. For this reason, it is common practice to add an error detection or an error correction code or the like to the data to be recorded. However, the applicant of the present application has previously described, for example, Japanese Patent Application No. 61-9389.
No. 2 proposes a data transmission method as shown in the specification and drawings. In this technique, additional information is added to the end of data to be transmitted and then arranged two-dimensionally.
A first error correction code is formed for data in each row of the dimensional array, and a second error correction code is formed for data in each column, so as to constitute a so-called product code. At the time of recording, data is sequentially read in the row direction of the product code, and is sequentially recorded in each of the data signal areas on the disk.

D. Problems to be Solved by the Invention By the way, each length of the servo signal area and the data signal area on the disk is, for example, 2 bytes and 16 bytes, respectively, in terms of bytes. The row length (length of one row) of the product code in the row direction is, for example, 52 bytes.

Therefore, when the data formed by the product code is sequentially recorded in each data signal area, the position divided by each servo signal changes for each row.
Data recorded in one data signal area may be distributed over two rows of the product code.

Therefore, if a servo signal error occurs during signal reproduction or the like, even if a single servo signal fails and data in one data signal area fails, the product code In the above, an error exists over two rows, and as a result, the error correction capability in the column direction is reduced.

Therefore, the present invention has been made in view of the above-described conventional problems,
An object of the present invention is to provide a data recording method in which data recorded in one data signal area between servo signal areas does not extend over two rows of the product code.

E. Means for Solving the Problems The data recording method according to the present invention has a servo signal area in which servo signals are recorded on concentrically or spirally formed tracks in order to achieve the above object. In a data recording method of sequentially recording a data signal in each data signal area on a disk in which at least a data signal area to which a data signal is written is provided alternately, data to be recorded is determined according to the length of one row. A two-dimensional array is formed by sequentially dividing each constant number, and a product code is formed by adding an error detection / correction code. A product code between the two servo signal areas having a continuous sequence length in the row direction of the product code is formed. The sequence length in the row direction or the length of the data signal area is selected so as to be an integral multiple of the length of the data signal area.

F. Action Since the length of the data of one line of the product code is an integral multiple of the data length of the data signal area, an integer number of data of the data signal area are arranged without excess or shortage in the one row, The data in one data signal area does not extend over two rows, and even if the data in one data signal area becomes an error due to a servo signal error or the like, only one error row is required.

G. Embodiment An embodiment in which the data recording method of the present invention is applied to data recording on a magneto-optical disk will be described below with reference to the drawings.

FIG. 1 shows the data structure of a so-called product code as the data structure of one sector of the magneto-optical disk to be recorded according to the present embodiment, and FIG. 2 shows the recording of the magneto-optical disk 1 on which the data is recorded. The format is shown. First, in FIG. 2, a data signal area 4 in which a data signal and an address signal are written is provided between servo signal areas 3 in which servo signals are recorded in a so-called pit form. They are provided alternately along tracks 2 in the circumferential direction of the magneto-optical disk 1. The lengths of the servo signal area 3 and the data signal area 4 are, for example, 2 bytes and 13 bytes, respectively, in bytes. Next, the data sequentially recorded in each data signal area 4 has a product code configuration as shown in FIG. 1, and the sequence length of the product code in the row direction is the same as the servo signal area 3 in FIG. For example, the length is set to 52 bytes so as to be an integral multiple of the length (13 bytes) of the data signal area 4 between them. Therefore, in one row of the product code, four pieces of data of the data signal area 4 are arranged without excess or shortage, and the data of one data signal area 4 does not extend over the two rows of the product code.

G-1.1 Data Structure of Sector (FIG. 1) Here, in this embodiment, the data structure of one sector to be recorded on the magneto-optical disk will be described in detail with reference to FIG.

In the magneto-optical disk, the unit data amount recorded in one sector in a recording track is, for example, 512 bytes in consideration of use as an information recording medium for a computer and the like. FIG. 1 shows an example of a data structure when one sector is 512 bytes. That is, the original valid data is 51 of data D _{0 to} D _{511 in} FIG.
Although it is 2 bytes, 16 bytes of additional information is added after the data D _{0 to} D ₅₁₁ to be 528 bytes, which is divided into 48 bytes in a row direction at a fixed value of 48 bytes, and 48 bytes in a row direction and a column. It is arranged two-dimensionally as 11 bytes (48 × 11 = 528) in the direction. That is, a two-dimensional matrix arrangement of 11 rows and 48 columns is formed. Where 12 of the 16 bytes
The bytes are reserved information, for example, information such as link information to the next sector and data identification information are inserted. Also,
For a total of 524 bytes of data including the reserved area data, a 4-byte error detection code EDC is generated and inserted into the last 4-byte area of 16 bytes of additional information.

With the first error correction code C ₁ of 4 byte each is added to more than 528 bytes of the two-dimensional array data each row of data (48 bytes), an error correction code C ₁ of the first is added The second error correction code C2 of ₂ bytes is added to the data (11 bytes) of each column of the two-dimensional array data (572 bytes), and a total of 676 bytes, a product code of 13 rows and 52 columns Is configured. Here, the first
And the second error correction code is, for example, C ₁ (52,4
8) Reed-Solomon code and C ₂ (13,11) Reed-Solomon code may be used. The two-dimensional array data having such a product code configuration is read at least one row at a time in the row direction, and is sequentially recorded in the data signal area 4 of the disk.

G-2. Recording Format (FIG. 2) Next, the recording pattern and track recording form on the magneto-optical disk on which the two-dimensional array data having the product code configuration is recorded will be described in more detail.

In FIG. 2, the magneto-optical disk 1 has a so-called 5
In the case of the inch type, the diameter is about 13 cm, and one side has a storage capacity of 300 Mbytes or more. This disc 1
The track 2 is rotated at a constant angular velocity, and as one track per rotation, for example, concentrically or spirally.
And data is recorded. 18 tracks per side
2,000 to 20,000, and each track is
As shown in (1), it is divided into (n + 1) sectors, for example, 32 sectors. Next, the format of the sector is shown in FIG.
As shown in the enlarged view, servo signal areas 3 on which servo pits are recorded and data signal areas 4 on which data signals and address signals are written are alternately arranged. In the data signal area, an address signal such as a sector address is recorded and formed in the form of the pit, for example. The lengths of the servo signal area 3 and the data signal area 4 are, for example, 2 bytes and 13 bytes, respectively, when converted into bytes. Therefore, in the case of the present embodiment, since the data amount of the whole product code per sector is 676 bytes, data of one sector is recorded over 52 data signal areas 4 and the address signal recording is performed. Thus, one data signal area 4 is added, and a total of 53 sets of the servo signal area 3 and the data signal area constitute one sector.

Here, the row length of the product code in FIG. 1 in the row direction is 52 bytes, and the length of one data signal area 4 is 13 bytes. It is allocated without excess or deficiency, and the data of any one data signal area 4 does not extend over the two rows of the product code.

G-3. Magneto-optical disk device (FIG. 3) Next, the overall configuration of a magneto-optical disk device for realizing the recording method of this embodiment will be briefly described with reference to FIG.

In FIG. 3, for example, data to be recorded from a computer or the like via an interface, that is, two-dimensional array data having the product code configuration is read and supplied line by line in the row direction to an input terminal 11. . The input data is sent to the modulation circuit 12, subjected to predetermined modulation including bit conversion and the like, and then sent to the laser drive circuit 13.
The laser drive circuit 13 is supplied with a control signal in each mode of writing, reading, or erasing from the interface, and outputs a signal for driving the laser diode 21 of the optical pickup 20 in response to the control signal. At the time of recording and erasing, the timing drive pulse signal according to the channel clock CCK, which is the reference clock,
At the time of reading, a high-frequency drive signal is supplied to the laser diode 21.

The optical pickup 20 includes the laser diode 21
In addition, it comprises a photodiode 22 and two photodetectors 23 and 24 divided into four. The photodiode 22 detects the intensity of the laser light emitted by the laser diode 21. The photodetectors 23 and 24 detect, for example, the reflected light of the laser light from the magneto-optical disk 1 via an analyzer. One of the photodetectors 23 and 24 detects the positive component of the Kerr rotation angle, and the other detects the The negative direction component of the rotation angle is detected.

The motor 14 is servo-controlled by, for example, a PLL (Phase Locked Loop) by a motor servo circuit 15, and rotates the disk 1 accurately at a predetermined speed (angular speed).

Then, the laser beam output from the laser diode 21 irradiates the magneto-optical disk 1 and enters the photodiode 22. The output of the photodiode 22 according to the light intensity of the laser light is supplied to a sample-and-hold (S / H) circuit 17 via a DC amplifier circuit 16. In the S / H circuit 17, the sample-and-hold operation in response to the sample pulse SP ₄ is performed, APC (Automat this output to the laser drive circuit 13 via the APC amplifier 18
ic Power Control). Thus, the light intensity of the laser light output from the laser diode 21 is kept at a predetermined value.

The optical pickup 20 into which the reflected light of the laser light from the disk 1 is incident via an analyzer (not shown).
Are output to the preamplifier circuit 31, respectively. From the preamplifier circuit 31, a photodetection signal S _A (S _A = A + B + C + D + A ′ +) is a sum signal of the outputs from the respective light receiving regions of the photodetectors 23 and 24.
B '+ C' + D ' ) ( together containing a DC component) are sent directly to the focus servo circuit 32, the light detection signal and an output by the respective light receiving regions S _{B [S B = (AC-BD)} +
(A'C'-B'D ')], via the S / H circuit 33 for sampling and holding operation in response to the sample pulse SP ₄ is sent to the focus servo circuit 32. Then, a focus servo control signal generated by the focus servo circuit 32 based on the signals S _A and S _B is sent to the optical pickup 20, and focus control is performed.

Further, the light detection signal S _C (S _C =
A + B + C + D + A '+ B' + C '+ D') are sent to a peak value detection circuit 41, S / H circuits 51, 52, 53 and a sampling clamp circuit 61, respectively. Above light detection signal S _C
Is a detection signal of a pit pattern or a concavo-convex pattern in the servo signal area 3 of the disk 1 and the data signal area 4 in which only the address signal is recorded. In the peak value detecting circuit 41, the peak value of the light detection signal S _C is detected, further, performs detection of a predetermined pit pattern of the servo signal area 3 at specific pattern detection circuit 42,
This detection output is sent to the pulse generation circuit 44 via the delay circuit 43. The pulse generation circuit 44 generates a channel clock CCK as a reference clock synchronized with a predetermined pit of the pit pattern based on the detection output obtained by the unique pattern detection circuit 42, and generates a byte clock BYC and a servo. Byte clock SBC and sample pulses SP ₁ , SP ₂ , SP ₃ , SP ₄ , SP ₅ are formed and output. Although not shown, the channel clock CCK is supplied to all circuit blocks. The sample pulse SP ₁ is supplied to the S / H circuit 51,
SP ₂ is supplied to the S / H circuit 52, and the sample pulse SP ₃ is supplied to the S / H circuit 52. Also, sampling pulses SP ₄ is is supplied to the S / H circuits 17 and 33, is supplied to the sampling clamp circuits 61 and 62. Incidentally, the sample pulse SP ₅ is used for detection of the moving direction of the optical pickup 20, for example. Further, a gate pulse is supplied from the pulse generation circuit 44 to the peak value detection circuit 41 and the unique pattern detection circuit 42.

In each of the S / H circuit 51, 52 and 53, the sample-and-hold operation at each sample pulses SP _1, SP _2, SP ₃ is performed on the light detection signal S _C fed. The output from the S / H circuit 51 and the output from the S / H circuit 52 are
4 compares the levels. This comparison output is used as a signal for traverse counting by the tracking servo /
The signal is sent to the seek circuit 55 and to the multiplexer 56. From the multiplexer 56, a signal having a higher level among the signals from the S / H circuits 51 and 52 is selectively output and sent to the subtraction circuit 57. The subtraction circuit 57
Now, the signal from the multiplexer 56 and the S / H circuit 5
A difference signal from the signal from 3 is formed and sent to the tracking servo / seek circuit 55 as a tracking error signal. The tracking servo / seek circuit 55 performs tracking control and feed control of the optical pickup 20.

Then, the light detection signal S _C to the sampling clamp circuit 61, also = light detection signal S _D [S _D to the sampling clamp circuit 62 (A + B + C + D) - (A '+
B ′ + C ′ + D ′)] are respectively supplied from the preamplifier circuit 31. This light detection signal _SD is
This is a detection signal of data written in the data area 4 of the disk 1. In contrast, the light detection signal S _C that is supplied to the sampling clamp circuit 61 is a detection signal of the address stored at a rate of once per sector in the form of the pits to the area 4. Each signal by the sample pulse SP ₄ in each sampling clamp 61, 62 is sent to the multiplexer 63 are clamped, respectively.

The switching selection operation of the multiplexer 63 is controlled by a control signal from the sync detection / address decode circuit 64. For example, first, the light detection signal S _C via the sampling clamp circuits 61 and a multiplexer 63 analog-to-digital (A / D) converter 6
5 and converted to a digital quantity, and then sent to a demodulation circuit 66, the output from the demodulation circuit 66
Sent to address decode circuit 64 and sync (synchronous signal)
Is detected, and the address information is decoded. Then, according to the address information of the data to be read supplied from the computer or the like via the interface, when the address information matches the actual address, the multiplexer 63 is switched and controlled, whereby the light detection signal S for the data area 4 is controlled. _D is sent to the A / D converter 65 and the demodulation circuit 66, and data obtained by performing demodulation processing including pit conversion is output from the output terminal 67. This output data is sent to a computer or the like via the interface. At the time of writing data, a control signal is sent from the synchronization detection / address decode circuit 64 to the modulation circuit 12, and data to be written from the modulation circuit 12 is sent to the laser drive circuit 13 in accordance with the control signal. Has become.

Here, the switching control operation of the multiplexer 63 does not occur in one area 4 on the track 2;
This is always performed within the scanning time of the servo signal area 3.
This is because the entire two-dimensional array data of the product code is divisible by the length of the data signal area 4 and no odd data is generated. Therefore, the address signal and the data signal are mixed and recorded in the data signal area 4. This is because there is no need to do so. As a result, the switching operation between the address signal and the data signal at the time of reproduction does not occur in the eta signal region between the servo signals. For example, even if the disk rotation speed increases and the data transfer rate increases, the address The switching operation between the signal and the data signal can be performed with a margin.

G-4. Another Embodiment (FIGS. 4 and 5) FIG. 4 shows an example of a data structure for one sector of data recorded by a data recording method according to another embodiment of the present invention. In this case, the lengths of the servo signal area and the data signal area on the track of the magneto-optical disk serving as the recording medium are 2 bytes and 16 bytes, respectively.

In FIG. 4, 16 bytes of additional information is added after the above-mentioned original valid data D _{0 to} D ₅₁₁ (512 bytes) for one sector to make 528 bytes, which are divided every 44 bytes. Two-dimensional matrix array data of 44 bytes in the row direction and 12 bytes in the column direction are formed. Here, the 16-byte additional information is composed of 12-byte reserve information and a 4-byte error detection code EDC, as in the embodiment of FIG. Thus by adding a first error correction codes C ₁ 4 bytes per row (44 bytes) of the two-dimensional array data obtained by similarly 1 column direction 2-byte second per (12 bytes) Error correction code C ₂
Are added to form a product code composed of two-dimensional array data of 14 rows and 48 columns. Here, as the first and second error correction codes, for example, a C ₁ (48,44) Reed-Solomon code and a C ₂ (14,12) Reed-Solomon code may be used. The two-dimensional array data having such a product code configuration is read at least one row at a time in the row direction, and is sequentially recorded in each of the 16-byte data signal areas of the disk.

That is, in the embodiment of FIG. 4, the length of one data signal area is 16 bytes and the sequence length of the product code in the row direction is 48 bytes. Individual data can be allocated without excess and deficiency, and data in any one data number area is not distributed over two rows of the product code.

FIG. 5 shows an example of the data structure when the data size is 1024 bytes in the embodiment of FIG. In the example of FIG. 5, 32-byte additional information is added to 1024-byte data to form a total of 1056-byte data as 44 columns × 24 rows of two-dimensional matrix array data. Here, the 32-byte additional information is, for example, 28
Byte reserve information and 4-byte error detection code EDC
All of the data are inserted at the end of the last row (the 24th row) of the 44-column × 24-row two-dimensional array data.

Further, as in the example of FIG. 4, a first error correction code such as a C ₁ (48,44) Reed-Solomon code is generated for each row of the two-dimensional array, and for each column,
For example, a _second error correction code such as C ₂ (26,24) Reed-Solomon code is generated, and a total of 1248 bytes, 48 columns × 26
This constitutes a product code composed of two-dimensional array data of rows.
Also in this case, data for three data signal areas can be allocated to one row of the product code without excess or deficiency, and data of one data signal area does not extend over two rows.

Here, as for the sequence length of the product code in the row direction, there are many divisors such as the above-mentioned 48 (bytes) (in the case of 48, the divisor is 24, 16, 12, 8, 6, 4 By selecting numerical values (3, 2, and 8), it is possible to easily deal with a change in the disk format, particularly when the interval between servo signals (the length of the data signal area) changes. That is, for example, in the case of a 3.5-inch type disk, the number of servo signals per rotation (one rotation of the disk) is about the same as that of the 5-inch type (for example, per rotation) due to the demand for stability of servo operation and the like. If the track diameter is set to about 1300 to 1400), the interval between servo signals becomes narrow due to the overall small track diameter, and it becomes difficult to record as much as 16 bytes of data. Therefore, it may be necessary to change the format so that the number of bytes recorded in the data signal area between the servo signal areas is, for example, about 12 bytes. Even in such a format change, if the sequence length of the product code in the row direction is set to 48 bytes, even the 12-byte length of the data signal area after the change is divisible, and in this case, 4 The data in the data signal area can be arranged without excess or deficiency.

In addition, various changes can be made without departing from the scope of the present invention. For example, the sequence length of the product code in the row direction, the length of the data signal area, and the like are limited to the numerical values of the above embodiment. Needless to say, it can be set arbitrarily without setting.

H. Effects of the Invention According to the data recording method of the present invention, even if an error occurs in a servo signal and data in one data signal area becomes an error, an error over two rows of product codes does not occur. In addition, the error correction capability can be improved, and the capability can be maximized even in the case of a burst error. Further, when the servo signal error, when passing error information to C ₁ code, because there is no strides over two rows error handling is easy. Furthermore, since the entire two-dimensional array data of the product code is not divisible by the length of the data signal area, and there is no odd data, it is not necessary to mix and record address signals and data signals in the data signal area. No switching operation between the address signal and the data signal occurs in the data signal area between the servo signals.

[Brief description of the drawings]

FIG. 1 is a diagram showing a data structure for one sector of data to be recorded by a data recording method according to an embodiment of the present invention, and FIG. 2 is a schematic diagram showing a recording pattern of a magneto-optical disk in the embodiment. FIG. 3 is a block diagram showing an overall configuration of an example of a magneto-optical disk drive to which the embodiment is applied, FIG. 4 is a diagram showing a data structure in another embodiment of the present invention, and FIG. FIG. 9 is a diagram showing a data structure when the size is 1024 bytes. 1 ... Magneto-optical disk 2 ... Track 3 ... Servo signal area 4 ... Data signal area

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-147052 (JP, A) JP-A-60-657 (JP, A) JP-A-60-1940 (JP, A) JP-A-62-1 192979 (JP, A) JP-A-61-260468 (JP, A) JP-A-59-28246 (JP, A)

Claims (1)

(57) [Claims] A disc provided with a servo signal area in which servo signals are recorded on concentric or spiral tracks and a data signal area in which at least a data signal is written is provided alternately. In a data recording method for sequentially recording data signals in a signal area, data to be recorded is sequentially divided into fixed numbers corresponding to the length of one row to form a two-dimensional array, and an error detection / correction code is added. A product code in which the sequence length in the row direction of the product code is selected to be an integral multiple of the length of the data signal area between two consecutive servo signal areas. Recording method.