JPH0447563A - Data recording method - Google Patents

Abstract

PURPOSE:To shorten the latency time for detecting a sector address by recording the sector address in plural segments in one sector concerned in a scattered form. CONSTITUTION:One track is divided into, for instance, ten sectors #0, #1, #2,... #9, and each of the sectors #0, #1, #2,... #9 is divided into, for instance, two hundred segments SG0, SG1, SG2, SG3,... SG199, where address segments SG0, SG50, SG100 and SG150 are arranged in a scattered form. By this method, the latency time for detecting a sector address is shortened, and the desired sector address is detected in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a data recording method particularly suitable for use in a sample servo type CD-RAM.

[Summary of the invention]

In a data recording method particularly suitable for use in a sample servo type CDRAM, the present invention provides a data recording method in which recording/reproduction processing is performed in units of a data sequence of a predetermined length, in which the data sequence is indicated in a unit data sequence. By providing multiple addresses, a desired sector can be accessed in a short time even when the sector size is large, such as in a CD-RAM.

[Conventional technology]

2. Description of the Related Art CDs (compact discs), which use magneto-optical discs as recording media and are capable of recording and reproducing data, have been proposed. C capable of recording/reproducing such data
D is called CD-RAM. The characteristics of CD-RAM are CD-ROM, which is only for data playback, and CD-W, which is write-once.
It is possible to maintain data compatibility with O.

In CD-RAM, one subcode block in CD format is one sector. One subcode block is 98 frames. Data is then recorded/reproduced sector by sector.

Note that the error correction code in a normal CD is not completed in one sector. Therefore, as an error correction coding method that can record and reproduce data on a sector-by-sector basis, the serious inventor first developed a sector-contained type CIRC (cross-interleaved code) as shown in Japanese Patent Application No. 118567-1983. (Solomon code).

[Problem to be solved by the invention]

In a CD-RAM, it is necessary to provide a sector address so that data can be recorded/reproduced in a desired sector. In a normal optical disc, a hexagonal area is provided in, for example, the first segment of one sector, and a sector address is recorded in this header area. Therefore, in CD-RAM as well, it is conceivable to record a sector address in the first segment of one sector, for example.

However, in CD-RAM, in order to maintain data compatibility, one subcode block is divided into one sector (
98 frames). Therefore, the sector size is larger than that of a normal optical disc. When the sector size is large like this, if the sector address is recorded only in the first segment of one sector, there will be a large number of track jumps until the segment in which the sector address is recorded is played back. It takes a long time to access the sector.

Therefore, an object of the present invention is to provide a data recording method that allows access to a desired sector in a short time even when the sector size is large, such as in a CD-RAM.

[Means to solve the problem]

The present invention relates to a data recording method in which recording/reproducing processing is performed in units of data sequences of a predetermined length, characterized in that a plurality of addresses indicating the data sequences are provided within a unit data sequence. It is.

[Effect]

Since sector addresses are distributed and recorded in a plurality of segments within one sector, rotational waiting time when detecting a sector address is shortened, and a desired sector address can be detected in a short time.

〔Example] Examples of the present invention will be described in the following order.

a. Arrangement of servo area ai Ordinary CD frame format a2. EFM
Example of servo area arrangement in case of modulation a3. Other examples of servo area arrangement in case of EFM modulation a4. Example of servo area arrangement in case of ESM modulation a5. Another example of the arrangement of the servo area in the case of ESM modulation is an example of a CD-RAM using the sample servo method. Regarding the arrangement of the servo area, the present invention is applied to a CD-RAM using the sample servo method.

When implementing a sample servo type CD-RAM, consideration must be given to the placement of the servo area in order to maintain stable servo and to facilitate error correction in the event of a defect in the servo area. This is to facilitate data compatibility with other CD variations.

In order to facilitate error correction when a defect occurs in the servo area, it is necessary to prevent one segment of data from spanning multiple error correction encoded sequences. In the CD recording format, data is developed into a frame structure and subjected to error correction encoding. Therefore, if one frame and one segment are made to correspond, one segment of data is completed with one error correction encoded sequence, so
Error correction processing becomes easier when a defect occurs in the servo area. Therefore, it is conceivable to make one frame correspond to one segment.

al. Frame format of a normal CD FIG. 5 shows the data structure of one frame of a normal CD. Note that on a CD, data is recorded by converting 1 byte (8 bits) into 14 channel bits by EFM (8-14) modulation. Between each byte, merging bits for three channel bits are arranged for DC component suppression.

As shown in FIG. 5, in the normal CD recording format, a sync pattern area 11 for (24+3) channel bits is provided at the beginning of one frame, and after this sync pattern area 11, a sync pattern area 11 for (14+3) channel bits is provided. Subcode area 1 (corresponding to 1 byte of data)
2 is provided. And following this, N14+3)X
I2) A data area 13 for channel bits (corresponding to 12 bytes of data) is provided, and ((14+3)X
4) A parity area 14 for channel bits (corresponding to 4 bytes of parity) is provided. Furthermore, ((14
+3) X 12) Data area 1 for channel bits
5 is provided, and a parity area 16 corresponding to ((14+3)×4) channel bits is provided.

Therefore, the capacity of one frame is: Sync pattern...(24+3) Channel bit subcode......(14+3) Channel bit data...(14+3)X12 channel bit parity... ...(14+3)X4 channel bit data...(14+3)X12 channel bit parity...(14+3)X4 channel pit total 588 channel bits.

In this one frame of data, consider the area where the servo area can be provided. In the sample servo method, a clock is reproduced using a reproduction signal from a clock reproduction pit in a servo area. Therefore, the sink pattern area 11 is unnecessary. Therefore, this sync pattern area 11 can be used as a servo bite.

Also, if the sector address is recorded, the subcode becomes unnecessary. Therefore, the subcode area 12 can be used as a servo byte.

a2. An example of the arrangement of servo areas in the case of EFM modulation FIG. 6 shows an example in which the sync pattern area 11 in a normal CD format is set as the servo area 21.

That is, in FIG. 6, at the beginning of one frame there is (2
4+3) Servo areas 21 for channel bits are provided. After this servo area 21, a subcode area 22 of (14+3) channel bits (corresponding to 1 byte of data) is provided. And following this ((1
4+3)XI2) A data area 23 for channel bits (corresponding to 12 bytes of data) is provided,
A parity area 24 for 4+3)×4) channel bits (corresponding to 4 bytes of parity) is provided. Furthermore, a data area 25 for ((14+3)x12) channel bits is provided, and a parity area 26 for ((14+3)x4) channel bits is provided.

In this way, one segment corresponds to one frame, making it easier to correct errors when a defect occurs in the servo area, and ensuring compatibility with other CDs/relations. In this case, 2 bits of data and parity for 561 channel bits (equivalent to 33 bytes) are
A servo area of 7 microbits (equivalent to 1.59 bytes) can be secured.

a3. Another example of the arrangement of servo areas in the case of EFM modulation is shown in FIG.
This is an example.

That is, in FIG. 7, at the beginning of one frame ((
Servo areas 31 for 24+3) + (14+3)) channel bits are provided. After this servo area 31, ((14+3)XI 2) channel bits (12
A data area 33 corresponding to bytes of data is provided, and a parity area 34 corresponding to N14+3)×4) channel bits (corresponding to 4 bytes of parity) is provided. Furthermore, a data area 35 for ((14+3)xl 2) channel bits is provided, and ((14+3)x4)
A parity area 36 for channel bits is provided.

In this case, a servo area of 44 channel bits (equivalent to 2.59 bytes) can be secured for 544 channel bits (equivalent to 32 bytes) of data and parity.

An example of the arrangement of servo areas in the case of a4.23M modulation In the above example, the data is subjected to EFM modulation as in a normal CD. However, in EFM modulation, it is necessary to provide three merging bits for DC component suppression between each byte, so there is a limit to the improvement in recording density. Therefore, a modulation method has been proposed in which one byte is converted into 16 channel bits and no merging bits for DC component suppression are required. Such a modulation method is called ES
This is called M(8-16) modulation.

FIG. 8 shows an example in which the sync pattern area 11 is set as the servo area 41 when 23M modulation is used.

That is, in FIG. 9, 60 characters are displayed at the beginning of one frame.
Servo areas 41 for channel bits are provided. After this servo area 41, a subcode area 42 for 16 channel bits (corresponding to 1 byte of data) is provided. Following this, a data area 43 for (16×12) channel bits (corresponding to 12 bytes of data) is arranged, and a variable f area 4 for (16×4) channel bits (corresponding to 4 bytes of parity) is arranged.
4 are arranged. Furthermore, a data area 45 for (16,×12) channel bits is provided, and a parity area 46 for (16×4) channel bits is provided.

In this case, a servo area of 60 channel bits (corresponding to 3.75 hides) can be secured for 528 channel bits (corresponding to 33 bytes) of data and parity.

Another example of the arrangement of servo areas in the case of a5.23M modulation FIG. 9 is an example in which the sync pattern area 11 and subcode area 12 are set as servo areas 51 and 57 when 23M modulation is used. In this example, one frame is divided into two equal parts, and servo areas 51 and 57 are provided in each part.

That is, in FIG. 9, there are 38 characters at the beginning of one frame.
Servo areas 51 for channel bits are provided. After this servo area 51, a data area 53 for (16 x 12) channel bits (corresponding to 12 bytes of data) is arranged, and a data area 53 for (16 x 4) channel bits (corresponding to 12 bytes of data) is arranged.
A parity area 54 (corresponding to byte parity) is provided. A servo area 57 for 38 channel bits is provided, a data area 55 for (t6x12) channel bits is provided, and a parity area 56 for (16x4) channel bits is provided.

In the CD recording format, one frame has data and parity of a similar pattern, so in this way, l
Divide the frame into two equal parts, each with servo areas 51 and 5.
7, the structure of each segment will be the same.

That is, in FIG. 9, a servo area 51, a data area 53, and a parity area 54 constitute one segment.

Further, the servo area 57, the data area 55, and the parity area 56 constitute another segment. The configurations of these two segments are the same.

In this case, for each segment, a servo area of 38 channel bits (equivalent to 2°375 bytes) can be secured for data and parity of 256 channel focuses (equivalent to 16 bytes).

In this way, since a servo area of 2 bytes or more is secured in 16 bytes, stable servo control can be performed.

b. Example of sample servo type CD-RAM FIG. 1 shows the configuration of a CD-RAM to which the present invention is applied. This CD-RAMI uses a magneto-optical disk as a recording medium. The external shape of CD-RAMI is said to be approximately the same as a normal compact disc.

The CD-RAMI is provided with a spiral or annular track T. Along this track T, data is recorded in the form of a magneto-optical pit (orientation of magnetization of a perpendicularly magnetized film) array. This CD-RAMI is rotated at CAV (constant angular velocity) or CL (constant linear velocity).

This CD-RAMI contains sectors (corresponding to subcode blocks on a normal CD) #01, #1, #2.
, . . , data is recorded/reproduced every time.

ESM modulation is used as the modulation method. A sector-completed CIRC code is used as the error correction code.

In this CD-RAMI, a sample servo method is used as a tracking method.

That is, one sector further includes a plurality of segments SGO,
It is divided into SGI, SG2, etc., and a servo area is provided for each segment. In each servo area, as shown in FIG. 2, servo bits PI and P2 are arranged with the same offset from the track center, and a bit P3 for clock reproduction is arranged. Using the reproduction signal level of these servo bits P1 and P2,
Tracking servo can be applied. Further, a clock is formed from the reproduced signal of the clock reproduction pin P3, and data is recorded/reproduced using this clock.

The recording format of this CD-RAM will be explained in detail.

FIG. 3 shows an example of the recording format of such a CD-RAM 1. Note that this example corresponds to the example shown in FIG.

That is, as shown in FIG. 3A, one track is divided into, for example, ten sectors #0, #1, #2, . . . #9. Each sector #0, #1, #2,...#9 is
As shown in Figure 3B, 100 segments 5CO1
sci, SG2, SG3, ... 5G199. One segment corresponds to 1/2 frame.

Note that in D, one subcode block consists of 98 frames, so if one frame is simply defined as two segments, one sector will be divided into 196 segments. However, in this example, since the servo area is also allocated to the subcode area, it is necessary to arrange sector addresses. This sector address may be internalized within the servo area, but in this example, four sectors of address segments are allocated so that the sector address can be detected reliably at high speed. Therefore, one sector has (196+4=100) segments.

Among these segments, segment SGO, segment SG50, segment SC;100, segment 5
G150 is used for address. A sector address is recorded in this address segment. other 1
96 (98 frames worth) segments SGI, SG2
, SG3, . . . , SG51.3052, . . . are segments for recording user data.

In this example, the segment SG for the address is thus
O, segment SG50, segment 100, and segment 5G150 are distributed and arranged. In this way, segment SCO for address, segment 5G50
, segment 100, and segment 5G150 are distributed, the rotation waiting time when detecting the lid address is shortened.

Figure 3C shows address segments SGo and SG50.
．． 100,5G150. As shown in FIG. 3C, the first two segments for addresses.
An area equivalent to 375 bytes is defined as a servo area 61.

Following this, there is a sector mark area 62.2 corresponding to 1 byte, and a sector number area 63.2 corresponding to 3 bytes.
A parity area equivalent to 64 bytes, a sector mark area equivalent to 1 byte, 65, a sector number area equivalent to 3 bytes, and a parity area 67 equivalent to 2 bytes are provided. In these areas equivalent to 12 bytes, data is recorded using embossed bits. The area corresponding to 4 bytes following this is defined as a laser control area 68.

The 343 diagram shows the structure of the data segment. As shown in the third diagram, the area equivalent to the first 2.375 bytes of the data segment is the servo area 7.
1. Following this, a user data area 72 corresponding to 12 bytes is provided. The area corresponding to 4 bytes following this is defined as a parity area 73.

When recording/reproducing data in such a format, sector-contained CIR is used as shown in Figure 4.
Error correction encoding processing is performed using C.

Segments SG1 and S excluding address segments
G2, SG3, ..., data segment sgO1s
gl, sg2, . . . Sector-contained CIR
When performing error correction encoding processing using C, the fourth
As shown in the figure, data segment sgO1sgl,s
Each data of g2, . . . 5g195 is arranged in a two-dimensional array. Then, error correction encoding processing is performed twice on the C1 sequence and the Ct sequence.

If a defect occurs in the servo area, the reproduced RF signal level decreases and the data in that segment becomes erroneous.

As shown in Figure 4, one segment of data is completed with one error correction coding sequence, so error information can be returned in units of 1/2 frame, making subsequent error correction management easier. be.

In such a recording format, each segment has a similar structure, and two segments constitute one frame, so it is suitable for writing data twice or recording corresponding data. For example, in Figure 4, if Japanese data is recorded in the upper segment (even-numbered segment) and English data is recorded in the lower segment (odd-numbered segment), audio multiplexing can be easily performed. Can be processed.

Furthermore, if error correction encoding processing is performed completely independently on the segments placed at the top and the segments placed at the bottom, the segments placed at the top and the segments placed at the bottom can be separated. Can be processed as completely independent data.

Furthermore, in this recording format, scrambling is performed on a segment-by-segment basis, so there is good compatibility between physical format processing and logical format processing.

〔Effect of the invention〕

According to this invention, since sector addresses are distributed and recorded in multiple segments within one sector, the rotational waiting time when detecting a sector address is shortened, and a desired sector address can be detected in a short time. .

[Brief explanation of the drawing]

Fig. 1 is a plan view showing the external configuration of a CD-RAM to which this invention is applied, Fig. 2 is a route map used to explain the servo area, and Fig. 3 is a recording format of a CD-RAM to which this invention is applied. A route map showing an example, FIG. 4 is a route map used to explain error correction encoding in a CD-RAM to which this invention is applied, and FIGS. 5 to 9 are route maps for a CD-RAM to which this invention is applied. FIG. 3 is a route map used to explain the arrangement of servo areas. Explanation of main symbols in the drawings 1: CD-RAM, 21.31, 41, 51.61.
71: Servo area.

Claims (1)

[Claims] A data recording method in which recording/reproducing processing is performed in units of data sequences of a predetermined length, characterized in that a plurality of addresses indicating the data sequences are provided within the unit data sequence. Data recording method.