Data recording method

Abstract: A data recording method by which data of a compact disk can be recorded well onto a magneto-optic disk of the ISO format. Data of a compact disk are recorded onto a 5-inch magneto-optic disk (ISO format) of the 512 bytes/sector type of the CS system. The sector size of the magneto-optic disk is 610 bytes. Data included in one sector (98 frames) of the compact disk are 2, 352 bytes and subcodings of P to W are 96 bytes. Data for one sector are divided into data groups A to H to construct a data format. A CRC is added to each data group. Further, a parity 2 (Reed-Solomon code) is added. Data (3, 050 bytes) for one sector of the compact disk to which the CRCs, parities and so forth are added are recorded across 5 sectors of the magneto-optic disk. Data of a compact disk can be recorded onto a magneto-optic disk having a different sector size, and since error correction codes or error detection codes are added using the remaining area, the data can be recorded with a high degree of accuracy.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a data recording method suitably applied to record data of a compact disk format onto a magneto-optic disk, for example, of the ISO format. 2. Description of the Related Art Conventionally, ISO (International Standardization Organization) formats for 3.5- and 5-inch magneto-optic (MO) disks have been proposed. Fig. 1 shows a sector format for a 5-inch magneto-optic disk of the 512 bytes/sector type wherein a CS (continuous servo) system is employed as a servo system. Referring to Fig. 3, reference character "SM" denotes a sector mark. The pattern of the sector mark "SM" has a 5-byte length and is "1 1⊘ 0 6 1 6 0 1 4 1 6 0 6 1 6 0 6 1 1⊘ 0 2 1 1 0 2 1 1 0 2 1 1 0 1 ". Here, 1 a and 0 b are channel bits and represent that "1" and "0" appear continuously by quantities a and b, respectively. Reference characters "VFO1" to "VFO3" denote each a VFO sink (PLL). The patterns of them are continuous patterns and individually such as follows: VF01 - 010010010010.....0010 (12 bytes) VF02 - 100100100100.....0010 (8 bytes) 000100100100.....0010 (8 bytes) VF03 - 010010010010.....0010 (12 bytes) Reference character "AM" denotes an address mark. The pattern of it has a 2-byte length and is "0100100000000100". Reference characters "ID1" to "ID3" denote each an address and have a same pattern. Each of the addresses "ID1" to "ID3" includes two bytes for a track number and one byte for a sector number recorded in the (2. 7) modulation. It further includes a CRC of 16 bits introduced therein and recorded in the (2. 7) modulation. A generating function of it is G(x) = x 16 + x 12 + x 5 + 1 Reference character "PO" denotes a postamble. A pre-format area thus ranges from the sector mark "SM" to the postamble "PO". Subsequently to the pre-format area, "TOF", "FLAG", "GAP" and "ALPC" are disposed. "TOF" corresponds to a mirror face which has no groove thereon. "FLAG" denotes a flag representing that writing has been performed. A pattern to be set includes repetitions of "100" by 5 bytes. "FLAG" is protected by gaps "GAP" of 3 bytes at each of the front and rear thereof. "ALPC" denotes a controlling area for a laser power. Reference character "SYNC" denotes a synchronizing signal for a data field. The pattern of it includes 3 bytes and is "010000100100001000100010010001001000001001001000". It is disposed subsequently to "VF03". Reference character "DATA FIELD" denotes a data field in which user data are to be recorded, and has 650 bytes. It is disposed subsequently to the synchronizing signal "SYNC". Reference character "BUFFER" denotes a margin for rotational jitters and includes 15 bytes. It is disposed subsequently to the "DATA FIELD". In this manner, one sector is constituted from a total of 746 bytes beginning with the sector mark "SM" and ending with the margin "BUFFER". Fig. 2 shows construction of the data field. Reference characters "SB1" to "SB3" denote synchronizing signals for the data field recorded in the synchronizing signal "SYNC" described above. Reference characters "RS1" to "RS40" denote each a re-sink and are disposed for each 10 bytes. Reference character "D1" to "D512" denote each user data (512 bytes), which are disposed in a matrix having 5 columns such that they are arranged, for each successive 5 user data of 5 bytes, in successive rows in each of which they are successively arranged from the left to the right as seen in Fig. 2. Reference characters "P1, 1" to "P3, 4" denote each control data (12 bytes) for exchanging operation and so forth, which are disposed in a similar manner subsequently to the user data. Reference character "(FF)" denotes a reserved area, and two such reserved areas (2 bytes) are disposed in a similar manner subsequently to the control data. Reference characters "C1" to "C4" denote each a CRC, and four such CRCs (4 bytes) are provided. The CRCs "C1" to "C4" are error detection codes for the user data "D1" to "D512", control data "P1 ,1" to "P3, 4" and reserved areas "(FF)". Reference characters "E1, 1" to "E5, 16" denote each a parity (ECC). The generating direction of the parities is the direction of a column. A (122, 106, 17) Reed-Solomon code x 5 interleave is used. This code allows correction of errors of up to 8 bytes and allows correction for dissipation of errors of up to 16 bytes. By the way, Fig. 3A shows a frame format of a compact disk (CD). Referring to Fig. 3A, the frame format includes a frame synchronizing signal SYNC of a 24-bit pattern, a subcoding of one symbol, data of 12 symbols, a P parity of 4 symbols, data of 12 symbols and a Q parity of 4 symbols disposed in this order. Here, one symbol includes 14 bits, and bits for the coupling between symbols (3 bits for each) are not shown. Such one frame corresponds to data of 6 samples (16 bits/sample) of two L and R channels sampled by 44.1 KHz. The subcoding includes 98 frames making up one block, which is illustratively shown in Fig. 4, while Fig. 5 shows a subcoding format. Referring to Fig. 5, one block is constituted from 96 bytes with two synchronizing patterns of S ⊘ and S 1 placed at the head thereof. Of 8-bit (after EFM demodulation) data P, Q, R, S, T, U, V and W of the third to 98th frames except the first and second frames corresponding to the synchronizing patterns S ⊘ and S 1 , P and Q are used for accessing, and the remaining 6 bits of R to W are used to a special application for a still picture, a display of characters on a specific background or the like. In the 98 frames (one sector) constituting one block of such subcoding, data of 588 samples (L0 to L587 and R0 to R587) of the two L and R channels, that is 2.352 bytes (1 byte = 8 bits) are included (Fig. 3B). In this manner, the sector format for a magneto-optic disk and the block (sector) format for a compact disk both specified by the ISO standards are completely different from each other and cannot be commonly used simply. EP-A-0 258 059, on which the preamble of claim 1 is based, discloses a method of converting from a CD-format to a CD-ROM format. GB-A-2 187 008 teaches to fill remaining data area with data for error correction coding. EP-A-0 397 472 shows the principle of separating odd and even data. SUMMARY OF THE INVENTION It is the object of the present invention to provide a modified recording method by means of which data of a compact disc (CD) can be recorded onto a magneto-optic disc of the ISO-format. According to the present invention as defined in claim 1 the input data in the compact disc format is divided into several fields of user data A - H. Between the fields of user data upper order bits and lower order bits as well as data of a left channel and of a right channel and even-numbered data and odd-numbered data are seperated. Thus, eight fields of user data A - H are generated, each comprising different data. The fields of user data are distinguished by at least one of the features left/right channel, even/odd-numbered data and lower/upper order bits. The fields of user data are disposed in a matrix order as shown in fig. 6 of the drawings. A parity code is used as error detection code and four different parities PARITY 1 - PARITY 4 are generated according to invention. Parities PARITY 1 and PARITY 2 are generated over all fields of user data A - H using a vertical generating direction as well as a horizontal generating direction. Two further parities PARITY 3 and PARITY 4 are generated separately for the fields of user data A - D and E - H, respectively. Due to the inventive deposition of parities 1 - 4, detection of an error of data of a compact disc and correction of such an error can be performed with high performance. Since data of one sector of the compact disc are divided into and disposed as fields of user data A - H, an error condition can be separately detected for each field of user data. In case the data have a high correlation, which is the case with audio data, a correcting data can be obtained by interpolation from adjacent correct data. A division of the data of one sector of a compact disc into several fields of user data A - H has the advantage that the distance between even-numbered data and odd-numbered data and data from the left channel and the right channel is rather high, so that a simultaneous damage of both even-numbered and odd-numbered data and data from the left channel and right channel is rather unlikely. Even if parity data is damaged, a correction can be performed on the basis of the remaining undamaged parities. For example, the sector size of a 5-inch magneto-optic disk (ISO format) of the 512-bytes/sector type of the CS system is 610 bytes. On the other hand, for example, data included in one sector (98 frames) of a compact disk are 2,352 bytes, and subcodings of P to W are 96 bytes. Consequently, when data of a compact disk are to be recorded onto a magneto-optic disk, for example, data (2,352 bytes) of the compact disk for one sector as well as subcodings (96 bytes) are recorded into 5 sectors (3,050 bytes = 610 bytes x 5) of the magneto-optic disk. Then, using the remaining area of 698 bytes (3, 050 bytes - 2, 352 bytes) or of, in case subcodings are involved, 602 bytes (3, 050 bytes - 2, 448 bytes), an error correction code or an error detection code is added. Consequently, data of a record medium can be recorded with a high degree of accuracy onto another medium of a different sector size, and for example, data of a compact disk can be recorded onto a magneto-optic disk. Such is suitable also for interpolation. The above and other objects, features and advantages of the present invention will become apparent from the following description and the appended claims, taken in conjunction with the accompanying drawings in which like parts or elements are denoted by like reference characters. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagrammatic view showing a sector format of a 5-inch magneto-optic disk of the 512 bytes/sector type of the CS system; Fig. 2 is a diagrammatic view showing a data field of a 5-inch magneto-optic disk of the 512 bytes/sector type of the CS system; Figs. 3A and 3B are diagrammatic views showing a frame format of a compact disk; Fig. 4 is a diagrammatic view showing a block (sector) format of a compact disk; Fig. 5 is a diagrammatic view showing a subcoding format of a compact disk; Fig. 6 is a diagrammatic view showing a data format when data of a compact disk are recorded onto a magneto-optic disk; and Fig. 7 is a diagrammatic view showing several combinations of individual sector sizes of a magneto-optic disk and a compact disk. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A data recording method of the present invention will be described subsequently by way of a preferred embodiment wherein it is applied to recording of data of a compact disk onto a 5-inch magneto-optic disk (ISO format) of the 512 bytes/sector type of the CS system. As described hereinabove, the sector size of a magneto-optic disk is a total of 610 bytes including 512 bytes of user data, 12 bytes of control data, 2 bites of reserved areas, 4 bytes of CRCs and 80 bytes of parities (refer to Fig. 2). On the other hand, one sector (98 frames) of a compact disk includes 2,352 bytes of data and 96 bytes of subcodings P to W as described hereinabove. Thus, in the present embodiment, data (2, 352 bytes) for one sector of a compact disk and subcodings (96 bytes) are recorded into 5 sectors of a magneto-optic disk. Fig. 6 shows a format of compact disk data recorded into 5 sectors (3, 050 bytes) of a magneto-optic disk. Referring to Fig. 6, each of reference characters A to H denotes user data of 294 bytes, and they are arranged in a matrix having 12 rows such that they are arranged, for each successive 12 user data of 12 bytes, in successive columns in each of which they are successively arranged from the top to the bottom as seen in Fig. 6. The user data A, C, E and G are disposed in this order in the horizontal direction, and also the user data B, D, F and H are disposed in this order in the horizontal direction. The user data A, C, E and G and the user data B, D, F and F are disposed in this order in the vertical direction, respectively. The user data A are upper order bits (L0f, L2f,..., L586f) of even-numbered data of the left channel. The user data B are lower order bits (L0l, L2l, ..., L586l) of even-numbered data of the left channel. The user data C are upper order bits (R0f, R2f, ..., R586f) of even-numbered data of the right channel. The user data D are lower order bits (R0l, R2l, ..., R586l) of even-numbered data of the right channel. The user data E are lower order bits (L1l, L3l, ..., L587l) of odd-numbered data of the left channel. The user data F are upper order bits (L1f, L3f, ..., L587f) of odd-numbered data of the left channel. The user data G are lower order bits (R1l, R3l, ..., R587l) of odd-numbered data of the right channel. The user data H are upper order bits (R1f, R3f, ..., R587f) of odd-numbered data of the right channel. Here, the suffix f denotes upper order bits (1 byte), and the suffix l denotes lower order bits (1 byte). The subcodings P to W of 12 bytes are disposed in the vertical direction (in vertical column) in front of the user data A to H, respectively. Further, subsequently to the user data A to H, areas of 2-byte control data AP to HP are provided, respectively, and 4-bytes of CRCs ACRC to HCRC are disposed therefor, respectively. In the areas of the control data AP to HP, for example, empty bits or CRCs, control data for the user data A to H, control data for the entire system or the like are disposed. The CRCs ACRC to HCRC are error detection codes for the user data A to H and control data AP to HP, respectively. Further, parities 3 are disposed adjacent or subsequently to the user data C and D. The parities 3 are provided for the user data A to D, control data AP to DP and CRCs ACRC to DCRC. The generating direction of the parities 3 is a horizontal direction, and a simple parity of EXOR (53, 52, 2) is used. Similarly, parities 4 are disposed adjacent or subsequently to the user data G and H. The parities 4 are provided for the user data E to H, control data EP to HP and CRCs ECRC to HCRC. The generating direction of the parities 4 is a horizontal direction, and a simple parity of EXOR (53, 52, 2) is used. Parities 2 are disposed between the parities 3 and the subcodings T and U. The parities 2 are provided for the user data A to H, control data AP to HP, CRCs ACRC to HCRC, parities 3 and parities 4. The generating direction of the parities 2 is a horizontal direction, and a (122, 106, 17) Reed-Solomon code x 25 interleave is used. This code allows correction of errors of up to 8 bytes without a dissipation or correction of up to 16 bytes when there is a dissipation. Further, parities 1 are disposed between the user data A, C, E and G and the user data B, D, F and H. The parities 1 are provided for the user data A to H, control data AP to HP, CRCs ACRC to HCRC, parities 2, parities 3 and parities 4. The generating direction of the parities 1 is a vertical direction, and a simple parity of EXOR (25, 24, 2) is used. In this manner, in the data format of Fig. 6, data of a compact disk include 2, 352 bytes (A to H); subcodings include 96 bytes (P to W); control data include 16 bytes (AP to HP); CRCs include 32 bytes (ACRC to HCRC); and parities include 554 bytes (parities 1 to parities 4), and a total of 3, 050 bytes is involved and corresponds to 5 sectors (3, 050 bytes) of a magneto-optic disk. The data of 3, 050 bytes are recorded across 5 sectors of a magneto-optic disk in a vertical recording direction (R/W direction). In short, 610 bytes (sector size) are recorded into each sector. In this manner, according to the present embodiment, data (2, 352 bytes) for one sector of a compact disk and subcodings (96 bytes) are recorded in a unit of 5 sectors (3, 050 bytes) of a 5-inch magneto-optic disk (ISO format) of the 512 bytes/sector type of the CS system. Since the CRCs ACRC to HCRC and parities 1 to 4 are disposed in the remaining area, detection of an error of data of a compact disk and subcodings and correction of such error can be performed well. Further, according to the present embodiment, since data for one sector of a compact disk, in short, data (L0 to L587 and R0 to R587) of 588 samples for each of the left and right, are divided into and disposed as user data A to H and CRCs ACRC to HCRC are added to them, respectively, an error condition can be detected for each of the divisional data. Accordingly, when there is an error in data, it is not necessary to determine all the data to be of no good, and in case the data have a high correlation such as audio data, correct data can be obtained by interpolation from adjacent correct data. Further, according to the present embodiment since data for one sector of a compact disk are divided into user data A to H and even-numbered data (L0, L2, ..., L586, and R0, R2, ..., R586) are disposed in the user data A to D while odd-numbered data (L1, L3, ..., L587, and R1, R3, ..., R587) are disposed in the user data E to H and parities 2 are disposed between them, the distance between the even-number data and the odd-numbered data can be made great, which can reduce otherwise possible simultaneous damage to both of them arising from a burst error. Consequently, even if one of them is damaged to make an error, it can be interpolated from the other data. Further, according to the present embodiment, since the length in a vertical direction is 25 bytes and data are recorded successively in the vertical direction, the depth of the interleave is 25 bytes. Consequently, errors arising from a great burst error can be corrected effectively with the parities 2. It is to be noted that, while, in the embodiment described hereinabove, data (2, 352 bytes) of a compact disk and subcodings (96 bytes) are recorded into 5 sectors (3, 050 bytes = 610 bytes x 5) of a 5-inch magneto-optic disk of the 512 bytes/sector type of the CS system, alternatively all data (3, 234 bytes = 33 bytes x 98) of a compact disk including error correction codes (784 bytes = 8 bytes x 98) may be recorded into 6 sectors (3, 660 bytes = 610 bytes x 6) of a magneto-optic disk. In this instance, the number of the remaining bytes is 426 bytes (3, 660 bytes - 3, 234 bytes), and error correction codes or error detection codes will be added using the area. Further, while, in the embodiment described above, the sector size of a 5-inch magneto-optic disk of the 512 bytes/sector type of the CS system is described to be 610 bytes (all data), the sector size may otherwise be considered to be 530 bytes only of data (information data) except for error correction codes, and also it can be considered that the sector size is 512 bytes only of user data (refer to Fig. 2). Similarly, also the sector size of a compact disk can be considered to include three kinds including 3, 234 bytes of all data, 2, 448 bytes of data and subcodings (information data), and 2, 352 bytes only of data. As relationships between the three sector sizes of a (610 bytes), a' (530 bytes) and a" (512 bytes) of a magneto-optic disk and three sector sizes of b (3, 234 bytes), b' (2, 448 bytes) and b" (2, 352 bytes) of a compact disk, there are nine relationships including a-b, a-b' (embodiment), a-b", a'-b, a'-b', a'-b", a"-b, a"-b' and a"-b" available. Fig. 7 shows an example of a unit sector number n of a magneto-optic disk and a sector number m of a compact disk to be recorded onto the magneto-optic disk in the individual relationships. For example, in the relationship of a'-b', data for one sector (2, 448 bytes) of a compact disk are recorded into 5 sectors (2, 650 bytes = 530 bytes x 5) of a magneto-optic disk. Then, using the remaining area of 202 bytes (2, 650 bytes - 2, 448 bytes), error correction codes or error detection codes are added. Further, while, in the embodiment described above, data of a compact disk are recorded onto a 5-inch magneto-optic disk of the 512 bytes/sector type of the CS system, the present invention can be applied similarly also to recording onto a magneto-optic disk of the SF system (sample servo system), or onto a 3.5-inch size magneto-optic disk or a magneto-optic disk of the 1, 024 bytes/sector type. For example, the case is considered wherein data of a compact disk are to be recorded onto a 3. 5-inch size magneto-optic disk of the 512 bytes/sector type of the CS system. In this instance, a portion of 106 rows in Fig. 2 is replaced by another portion of 104 rows, and the sector size is changed to 600 bytes. Thus, for example. data of 3.000 bytes should be produced excepting the parities 3 and parities 4 of Fig. 6 and recorded across 5 sectors of a magneto-optic disk. Further, while, in the embodiment described above, data of a compact disk are recorded onto a magneto-optic disk, the present invention can be applied similarly to any other case of recording onto a medium having a different sector size.

Claims: A data recording method for recording, onto a record medium specified for recording data of a sector size A thereon, data of a different sector size B, comprising the steps of: dividing, in order to record mB data into a record unit area of the record medium consisting of n sectors, n being an integral number equal to or greater than 1, m being an intergral number which is equal to or greater than 1 and satisfies the relationship of nA > mB, the mB data into a plurality of data groups, adding an error detection code to each of the data group using the region of nA - mB of the record unit area of the record medium; and recording the resultant data into the record unit area of the n sectors of the record medium, characterized in that the recording data is divided in fields of user data (A-H), whereby a first field of user data (A) comprises upper order bits (L0f, L2f, ... L586f) of even-numbered data of a left channel, a second field of user data (B) comprises lower order bits (L0l, L2l, ... L586l) of even-numbered data of the left channel, a third field of user data (C) comprises upper order bits (R0f, R2f, ... R586f) of even-numbered data of a right channel, a forth field of user data (D) comprises lower order bits (R0l, R2l, ... R586l) of even-numbered data of the right channel, a fifth field of user data (E) comprises lower order bits (L1l, L3l, ..., L587l) of odd-numbered data of the left channel, a sixth field of user data (F) comprises upper order bits (l1f, L3f, ... L576f) of odd-numbered data of the left channel, a seventh field of user data (G) comprises lower order bits (R1l, R3l, ... R587l) of odd-numbered data of the right channel, and an eighth field of user data (H) comprises upper order bits (R1f, R3f, ... R587f) of odd numbered data of the right channel; and the error detection code is a parity code, whereby first parities (PARITY 1) are provided for all fields of user data (A - H) using a vertical generating direction, second parities (PARITY 2) are provided for all fields of user data (A - H) using a horizontal generating direction, third parities (PARITY 3) are provided for the first, second third and forth field of user data (A - D) using a vertical generating direction, and forth parities (PARITY 4) are provided for the fifth, sixth, seventh and eighth field of user data (E - H) using a vertical generating direction. A data recording method according to claim 1. wherein data of the sector size A are user data of units of 512 bytes. A data recording method according to claim 2, wherein the data of the sector size B are data for 98 frames of a compact disk.

Inventors: YOICHIRO SAKO, YOICHIRO, SAKO
Applicants: SONY CORP, SONY CORPORATION
Application year: 1992
Main classification: G11B20
IPC codes: G11B20, G11B27