Abstract:
When recording layers were provided on both the front and back sides of an optical disk in order to increase the recording capacity, whether the reproducing surface of the optical disk taken out of the cartridge was the front side or the back side could not be determined. This problem can be solved by adding to the BCA, in addition to disk identification information: type information indicating whether a recording surface is provided on one side or both sides; side information indicating whether the surface with which reproduction is being performed is side A or side B; recording layer quantity information indicating whether the disk has a single layer or a double layer; information indicating the areas other than the BCA and the directions in which data on the read-in, data zones, and read-out are recorded/reproduced; and information indicating the presence/absence of a disk cartridge.

Description:
RELATED APPLICATION 
     This application is the U.S. National Phase under 35 U.S.C. §371 of International Application No. PCT/JP2011/003283, filed on Jun. 10, 2011, the disclosure of which Application is incorporated by reference herein. 
     TECHNICAL FIELD 
     The present invention relates to an optical information recording medium and recording reproducing device. 
     BACKGROUND ART 
     In the past, owing to higher densities using shorter wavelengths of semiconductor lasers and higher numerical apertures (NA) of objective lenses, greater capacities from CD to DVD and then to Blu-ray Disc (Trademark) have been accomplished. In recent years, however, the trend is toward creating multiple layers rather than higher densities to achieve greater capacities. BDXL (Trademark) has been standardized. That is, BD discs having multiple layers have been created. A BD disc having 33 GB per layer and achieving 100 GB with three layers is available. Furthermore, a BD disc having 32 GB per layer and achieving 128 GB with four layers is available. Because broadcast media have evolved and there are increasing amounts of moving picture contents, amounts of data handled by individuals and enterprises have continued to increase. It can be expected that there will be a demand for storage media having greater capacities in the future. One method available for achieving greater capacities consists of making laser light enter from both surfaces of an optical disc and forming recording layers on both front and rear surfaces of the disc. In optical discs, fingerprints and dust on the recording surfaces may affect the quality of signal when recording or playback is made. In some cases, cartridges are used to prevent adhesion of fingerprints and dust on the recording surfaces. 
     As set forth in Patent literature 1, a region known as a burst cutting area (hereinafter referred to as the BCA) is formed on the inner side of an optical disc such as CD, DVD, or Blu-ray Disc (Trademark). Optical disc drives, players, and recorders are required to provide reading compatibility with various discs. It has become increasingly difficult to discriminate discs. One means to discriminate discs is to contain information intrinsic to each disc within the BCA of the disc. The BCA is not essential to the existing DVD disc using a laser of a wavelength of 650 nm. However, in the Blu-ray Disc (Trademark) using a laser of a wavelength of 405 nm, information about individual identification codes and disc copy protection is included and so the BCA has become more important and is an essential item of the disc. On the other hand, Patent reference 2 discloses that the lead-in area on the inner side of a recordable Blu-ray Disc (Trademark), i.e., BD-RE, is partitioned into a first guard area (Guard 1), a PIC (Permanent Information &amp; Control data) area, a second guard area (Guard 2), information 2 area (Info 2), an OPC (Optimum Power Control) area, and other areas. Furthermore, it is set forth that the PIC area is used as a region previously recorded with data. 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Literature 1: JP-A-2011-18442 
         Patent Literature 2: JP application No. 2004-502291 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     When the recording capacity of an optical disc is increased by forming recording layers on both front and rear surfaces, it is impossible to discern whether the reading surface of the optical disc which has been taken out of the cartridge is the front surface or rear surface. 
     Accordingly, it is an object of the present invention to shorten the setup time of an optical disc having recording layers on its both surfaces. 
     Solution to Problem 
     As one example, the above object is achieved by contriving information recorded in each block of the BCA. 
     Advantageous Effects of Invention 
     According to the present invention, the setup time of the optical disc having recording layers on its both surfaces can be shortened. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram showing BCA data with identifier 111111. 
         FIG. 2  is a structural diagram of a single-layer, double-sided disc. 
         FIG. 3  is a structural diagram of a double-layer, double-sided disc. 
         FIG. 4  is a diagram showing the fundamental disc information data of the BCA data. 
         FIG. 5  is a diagram showing the fundamental disc information data of the BCA data on the other surface. 
         FIG. 6  is a structural diagram showing a counterclockwise spiral direction in a disc. 
         FIG. 7  is a structural diagram showing a clockwise spiral direction in a disc. 
         FIG. 8  is a structural diagram of a single-layer disc. 
         FIG. 9  is a structural diagram of a double-layer disc. 
         FIG. 10  is a structural diagram of recording layers of a disc. 
         FIG. 11  is a structural diagram of data frames of a disc. 
         FIG. 12  is a structural diagram of scrambled data frames of a disc. 
         FIG. 13  is a structural diagram of data blocks with 216 rows and 304 columns of a disc. 
         FIG. 14  is a structural diagram of LDC blocks of a disc. 
         FIG. 15   a  is a structural diagram illustrating first interleaving with respect to LDC blocks. 
         FIG. 15   b  is a structural diagram illustrating second interleaving with respect to LDC blocks. 
         FIG. 16  is a structural diagram of address information on a disc. 
         FIG. 17  is a structural diagram of access blocks of a disc. 
         FIG. 18  is a structural diagram of BIS blocks of a disc. 
         FIG. 19  is a structural diagram of BIS clusters of a disc. 
         FIG. 20  is a diagram showing the structure of ECC clusters of a disc. 
         FIG. 21  is a diagram showing the structure of recording frames of a disc. 
         FIG. 22  is a diagram showing a 1-7 modulation used on a disc. 
         FIG. 23  is a table of a sync signal pattern of sync frames. 
         FIG. 24  is a structural diagram showing the position of a BCA in a disc, used in the present invention. 
         FIG. 25  is a conversion table listing a modulation rule of a BCA in a disc, used in the present invention. 
         FIG. 26  is a diagram showing the shape of recording of a BCA on a disc, used in the present invention. 
         FIG. 27  is a structural diagram of BCA data in a disc, used in the present invention. 
         FIG. 28  is a table of a pattern of sync signals of BCA. 
         FIG. 29  is a structural diagram of ECC blocks in a BCA code. 
         FIG. 30  is a structural diagram of data blocks of BCA. 
         FIG. 31  is a block diagram of an optical disc recording/reproducing device. 
         FIG. 32  is a block diagram of an optical disc recording/reproducing device permitting access to both surfaces. 
         FIG. 33  is a block diagram of an optical disc recording/reproducing device permitting simultaneous access to both surfaces. 
         FIG. 34  is a structural diagram of (the front surface of) a disc cartridge. 
         FIG. 35  is a structural diagram of (the rear surface of) the disc cartridge. 
         FIG. 36  is a flowchart of setup processing when a disc is inserted. 
         FIG. 37  is a table showing the relationship between data spiral direction, fundamental disc information, and embodiments. 
         FIG. 38  is a diagram showing BCA data with identifier 000001. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
       FIG. 37  shows BCA reading directions in various embodiments of the present application, method of identifying BCA reading directions, information included in the BCA for identification of front and rear surfaces or surfaces A and B, and directions in which data in areas (excluding the BCA) (i.e., lead-in, data-zone, and lead-out) are recorded and reproduced. In the present embodiment, BCA reading direction and directions in which data (such as lead-in data, data-zone data, and lead-out data) are recorded and reproduced indicate the directions of rotation when a disc is viewed from a recording surface that is to be recorded and reproduced, indicating directions in terms of counterclockwise and clockwise. In the present expression, on a Blu-ray Disc (Trademark) of a disc structure of a single layer ( FIG. 8 ) or a double layer ( FIG. 9 ) having a recording surface or surfaces on one side, the BCA reading direction and data (lead-in, data-zone, and lead-out) reading direction are both counterclockwise. 
     Embodiment 1 is an embodiment in a case where both surfaces A and B have the same recording layer structure as the Blu-ray Disc (Trademark). In embodiments 2, 3, and 4, surface A has the same recording layer structure as the Blu-ray Disc (Trademark), but on surface B, the direction in which lead-in, data-zone, and lead-out data are recorded and reproduced is opposite to the direction on surface A, i.e., clockwise. In embodiment 2, the BCA reading direction on surface B is the same as on surface A, i.e., counterclockwise. In embodiments 3 and 4, the BCA reading direction on surface B is reverse to the direction on surface A, i.e., clockwise. 
     [Optical Disc and Optical Disc Recording/Reproducing Device] 
     An optical disc and recording/reproducing device therefor being a first embodiment of the present application is described by referring to  FIGS. 1-5 ,  10 - 31 ,  34 - 36 , and  38 . 
     [Disc (BCA Format)] 
     The BCA data format for a double-sided optical disc of the present invention is described. 
       FIG. 38  shows the BCA data format of data blocks permitting individual discrimination. In  FIG. 38 , longitudinal Byte indicates where each byte of data is located. Horizontal Bit indicates where each bit of data is located. Byte  0  of the BCA is a content code, where Bits  7  to  2  are an identifier. In this case, it is assumed that 000001 is set. Bits  1  and  0  of Byte  0  are a sequence number. When the BCA consists of a plurality of data blocks, the sequence number indicates where the sequence is located. The sequence numbers will be described later in connection with the description of the BCA. Byte  1  and Byte  2  are an identification code (IDs) of a manufacturer. Bytes  3  to Byte  15  are a unique number attached to each disc. That is, the number permits individual discrimination. Therefore, the recording/reproducing device can obtain an amount of individual information sufficient to provide fine copy management and disc management using the present information. Recordings are made while assigning a different individual identification number to each disc. In the case of a double-sided disc, the same ID (manufacturer ID code) and identification number (individual identification number) are assigned to the BCAs of both surfaces A and B. 
       FIG. 1  shows a data block format used in the BCA and permitting discrimination among optical disc types. In  FIG. 1 , vertical Byte indicates where each Byte of data is located. Horizontal Bit indicates where each Bit of data is located. Byte  1  of the BCA is a content code including Bits  7  to  2  which are an identifier. In this case, it is assumed that 111111 is set. Bits  1  and  0  of Byte  0  are a sequence number. When the BCA consists of a plurality of data blocks, the sequence number indicates where each sequence is located. Byte  1  indicates the type of a standard with which the optical disc is compliant. A disc type such as DVD, HD-DVD, or Blu-ray Disc (Trademark) is shown. Besides, recording characteristics such as ROM, Recordable, or Rewritable are shown. Byte  2  is a version number of the standard with which the disc is compliant. A recording/reproducing device can judge the presence or absence of recording/reading compatibility or reading compatibility with the present optical disc from the present information. Byte  3  indicates the fundamental physical characteristic information regarding the recording surface being read. Byte  4  indicates the fundamental physical characteristic information regarding the recording surface facing away from the reading surface.  FIGS. 4 and 5  show the fundamental physical characteristics of Bytes  3  and  4 . The fundamental physical characteristics include the presence or absence of a disc cartridge. Besides, type information indicating whether the recording surface is one surface or both surfaces is included. Also, surface information indicating whether the surface is A or B is included. Information indicating the number of recording layers, i.e., whether single layer or double layer, is included. Information about areas excluding the BCA (information that is unnecessary for embodiment 1) is included. Information about the direction in which lead-in, data-zone, and lead-out data are recorded and reproduced is included. Byte  3  of the BCA of surface A of a single-layer, single-sided optical disc or a double-layer, double-sided optical disc placed in a disc cartridge has recorded fundamental physical characteristic information on the reading side, the recorded information indicating both surfaces, surface A, single layer, counterclockwise, and the presence of a disc cartridge. Byte  4  includes recorded fundamental physical characteristic information on the opposite surface, the fundamental information indicating both surfaces, surface B, two layers, counterclockwise, and the presence of a disc cartridge. On the other hand, Byte  3  of the BCA on surface B includes recorded fundamental physical characteristic information on the surface on the reading side, the information indicating both surfaces, surface B, two layers, counterclockwise, and the presence of a disc cartridge. Byte  4  has recorded fundamental physical characteristic information on the opposite surface, the information indicating both surfaces, surface A, single layer, counterclockwise, and the presence of a disc cartridge. Byte  3  of the BCA of a bare two-layered optical disc having a recording surface on only one side and using no disc cartridge includes recorded fundamental physical characteristic information which indicates one surface, surface A, two layers, counterclockwise, and the absence of a disc cartridge. 
     In this way, by recording information about disc type, recording characteristics, version number of a standard with which the disc is compliant, type information, surface information, and the number of recording layers in the BCA, the information permitting discrimination of the type of the optical disc, disc discrimination that is needed to be done either when the disc is inserted into the recording/reproducing device or when the power supply is turned on is facilitated. A setup of various parameters can be made reliably, quickly, and easily. Furthermore, information regarding disc type and state can be offered to the host quickly. 
     [Shapes of Discs] 
     The shapes of optical discs used in the present invention are described.  FIG. 2  shows a single-layered, double-sided recordable optical disc.  FIG. 3  shows a double-layered, double-sided optical disc. In the single-layered, double-sided optical disc shown in  FIG. 2 , recording surfaces exist on both surfaces A and B. A cover layer protecting the recording surface A or B, a recording layer consisting of a recording layer on which signal is recorded or of a reflective film, and an underlying substrate layer are formed in this order from the recording surface A or B toward the center of the disc. Also, in the double-layered, both-sided optical disc shown in  FIG. 3 , recording layers exist on both surfaces A and B. A cover layer protecting the recording surface A or B, a recording layer (L 1 ) on which signal is recorded, a space layer forming a space with another recording layer, another recording layer (L 0 ) on which signal is recorded, and a deeper substrate layer are formed in turn from the recording surface A or B toward the center of the disc. Each of  FIGS. 8 and 9  shows a single-sided recordable optical disc. The structure of the recording surface is similar to the cases of  FIGS. 2 and 3 . 
     The structures of the recording layers of the single-layered, double-sided optical disc and the double-layered, double-sided optical disc are shown in  FIG. 10 .  FIG. 10  schematically shows a cross section of each disc. The left side shows the inner side, while the right side shows the outer side. The L 0  disc structure of  FIG. 10(   a ) shows the disc structures of recording layers L 0  of the single-layered, double-sided optical disc and the double-layered, double-sided optical disc. The L 1  disc structure of  FIG. 10(   b ) shows the disc structure of the recording layer L 1  of the double-layered, double-sided optical disc. 
     In the L 0  disc structure of  FIG. 10(   a ), indicated by  1001  is a BCA (Burst Cutting Area) in which information intrinsic to the disc is recorded. Indicated by  1002  is Inner Zone  0  in which information about attributes concerning the disc, control information, and so on are recorded. This Inner Zone  0  ( 1002 ) is also referred to as the Lead-in. Indicated by  1003  is Data Zone  0  in which user data such as AV data or the like is recorded. Indicated by  1004  is Outer Zone  0  in which control information and so on are recorded. The Inner Zone  0  ( 1002 ) consists of Protection Zone  1  ( 1005 ), PIC ( 1006 ), Protection Zone  2  ( 1007 ), INFO 02  ( 1008 ), reserved ( 1009 ), and INFO 01  ( 1010 ). The Protection Zone  1  ( 1005 ) is an area for isolating the BCA ( 1001 ) and PIC ( 1006 ) from each other. Data have been previously recorded in the Protection Zone  1  ( 1005 ) and PIC ( 1006 ). New data are recorded in the other areas. The Protection Zone  1  ( 1005 ) is an area for isolating the more inner side and the PIC ( 1006 ) from each other. Disc information to be stored permanently, i.e., information about disc type and recording characteristics, information about disc size, information about version of a standard with which the disc is compliant, fundamental physical characteristic information such as information about the number of recording layers (e.g., whether single layer or two layers), information about the presence or absence of the BCA, and information (such as information about a recommended write strategy of L 0  and recording rate) is stored in the PIC ( 1006 ). Thus, a high-frequency modulated (HFM) group is formed. The Protection Zone  2  ( 1007 ) is an area for isolating the PIC ( 1006 ) and the INFO 02  ( 1008 ) from each other. Control information is recorded in the INFO 02  ( 1008 ). Reserved ( 1009 ) is a reserved area. Control information is recorded in the INFO 01  ( 1010 ). The Outer Zone  0  ( 1004 ) consists of INFO 3 / 4  ( 1011 ) and Protection Zone  3  ( 1012 ). Control information is recorded in the INFO 3 / 4  ( 1011 ). The Protection Zone  3  ( 1012 ) isolates the INFO 3 / 4  ( 1011 ) from the further outer side. The arrow from the inner side toward the outer side of the L 0  disc structure of  FIG. 10(   a ) indicates that data is recorded on a continuous spiral track, from the inner side toward the outer side of the recording layer L 0  of the single-layered, double-sided optical disc and the double-layered, double-sided optical disc. 
     In the L 1  disc structure of  FIG. 10(   b ), indicated by  1014  is Inner Zone  1  in which information about attributes about the disc, control information, and so on are recorded. This is also referred to as Lead-out. Indicated by  1015  is Data Zone  0  in which user data such as AV data is recorded. Indicated by  1016  is Outer Zone  1  in which control information and so on are recorded. The Inner Zone  1  ( 1014 ) consists of Protection Zone  1  ( 1017 ), PIC ( 1018 ), Protection Zone  2  ( 1019 ), INFO 02  ( 1020 ), reserved ( 1021 ), and INFO 01  ( 1022 ). The Protection Zone  1  ( 1005 ) and PIC ( 1006 ) are areas in which data have been previously recorded. New data are recorded in the other areas. The Protection Zone  1  ( 1017 ) is an area for isolating the more inner side and the PIC ( 1018 ) from each other. Disc information to be stored permanently, i.e., information about disc type and recording characteristics, information about disc size, information about the version of a standard with which the disc is compliant, fundamental physical characteristic information such as information about the number of recording layers (e.g., whether single layer or two layers), information about the presence or absence of the BCA, and information (such as information about recommended write strategy of L 1  and recording rate) is stored in the PIC ( 1018 ). A high-frequency modulated (HFM)) group is formed. The Protection Zone  2  ( 1019 ) is an area for isolating the PIC ( 1018 ) and the INFO 02  ( 1020 ) from each other. Control information is recorded in the INFO 02  ( 1020 ). The reserved ( 1021 ) is a reserved area. Control information is recorded in INFO 01  ( 1022 ). The Outer Zone  1  ( 1016 ) consists of INFO 3 / 4  ( 1023 ) and Protection Zone  3  ( 1024 ). Control information is recorded in the INFO 3 / 4  ( 1023 ). The Protection Zone  3  ( 1024 ) isolates INFO 3 / 4  ( 1023 ) from the further outer portion. The arrow directed from the outer side toward the inner side of the L 1  disc structure of  FIG. 10(   b ) indicates that data is recorded on a continuous helical track from the outer surface toward the inner surface of the recording layer L 1  of the double-layered, double-sided optical disc having two layers on each surface. 
     The optical discs having recording surfaces on both surfaces as shown in  FIGS. 2 and 3  make use of a disc cartridge during use in order to prevent adhesion of hands grease, smudges, and scratching of the recording surfaces.  FIG. 34  shows the rear surface of the disc cartridge.  FIG. 35  shows the front surface of the disc cartridge. Here, both surfaces of the disc cartridge have the same shape because the cartridge is compliant with both surfaces. As shown in  FIGS. 34 and 35 , disc information holding portions  3401 ,  3501 , timing information holding portions  3403 ,  3503 , a cartridge positioning hole  3402 , a shutter  3405 , and so on are formed on the body  3406  of the cartridge. Since the present disc cartridge is compliant with both surfaces, the disc information holding portions  3401 ,  3501 , and timing information holding portions  3403 ,  3503  which correspond to both surfaces are respectively disposed on the opposite surfaces of the disc cartridge. Seven disc information holding portions  3401  or  3501  are arranged per disc surface. Information is set by the presence or absence of concavities on the cartridge surface. Furthermore, seven timing information holding portions  3403  or  3503  are arranged in conformity with the number of the disc information holding portions  3401  or  3501 . The timing information holding portions  3403  and  3503  set information by the presence or absence of concavities on the cartridge surface. 
     The information about the fundamental physical characteristics of the PICs ( 1006  and  1008 ) present on the inner side of the disc does not always need to contain type information indicating whether the recording layer is one surface or two surfaces (i.e., fundamental physical characteristic information recorded in the BCA), surface information indicating whether the surface is A or B, and the information indicating whether a disc cartridge is present or absent. When these sets of information are not contained in the PICs, the stamper as used for single-sided discs can be used for both surfaces A and B of double-sided discs. This suppresses the cost of manufacturing double-sided discs. The discs can be supplied economically. 
     [Processing for Encoding of Data] 
     Processing for recording user data is described. As shown in  FIG. 11 , user data is divided into parts each having 2048 bytes. An error detection code of 4 bytes is attached to each data element, thus constituting data frames of 2052 bytes. Then, as shown in  FIG. 12 , each data frame is scrambled, thus forming scrambled data frames. Then, as shown in  FIG. 12 ,  32  scrambled data frames are collected. Then, they are rearranged on the column order. As shown in  FIG. 13 , data blocks in 216 rows and 304 columns are constituted. As shown in FIG.  14 , each column of the data blocks is encoded by Reed-Solomon encoding of 248, 216, and 32. A parity of 32 bytes is added. New LDC (Long Distant Code) blocks in 248 rows and 304 columns are constituted. The LDC blocks are subjected to the following first interleaving process and second interleaving process. As shown in  FIG. 15   a , in the first interleaving process, data elements in the even-numbered columns and the following data elements in the odd-numbered columns are rearranged so as to be interleaved. Thus, blocks in 496 rows and 152 columns are constituted. In the second interleaving process, as shown in  FIG. 15   b , with respect to the rearranged blocks in 496 rows and 152 columns, rows are shifted from above, two rows at a time. The first 2 rows are not shifted. The next 2 rows are shifted to the left by three bytes. The next 2 rows are shifted by 6 bytes. The next 2 rows are shifted to the left by 9 bytes. In this way, a rearrangement is performed such that the amount of shift is increased by 3 bytes at a time. Data subjected to the first and second interleaving processes constitute LDC clusters. 
     On the other hand, addresses added to each such data block are generated as follows. 
     As shown in  FIG. 16 , each data block is divided into 16 address units. 9 bytes of address information are assigned to each address unit. The 9 bytes consist of 4 bytes of address, 1 byte of flag information, 5 bytes of address, and a party attached to the flag information. The address is interleaved, and a matrix with 6 rows and 24 columns is generated. At the same time, 32 units of 18 bytes of user control data are arranged in a matrix with 24 rows and 24 columns. 
     The above-described matrix with 6 rows and 24 columns and the matrix with 24 rows and 24 columns are coupled together to constitute access blocks with 30 rows and 24 columns as shown in  FIG. 17 . The columns of the access blocks are encoded by Reed-Solomon encoding (62, 33, 32) and a parity of 32 bytes is attached to form BIS (Burst Indicating Subcode) blocks with 62 rows and 24 columns as shown in  FIG. 18 . Data in the BIS blocks are rearranged to constitute BIS clusters with 496 rows and 3 columns as shown in  FIG. 19 . 
     The LDC cluster is divided into ones each having 38 columns One column of BIS cluster of data is inserted between them. Thus, ECC clusters shown in  FIG. 20  are constituted. 
     Twenty bits of frame sync signal are attached to the head of 155 bytes of data in each row of the ECC clusters. The 155 bytes of data are divided into leading 25 bits of data and following 45 bits of data. A DC control bit is interposed to constitute recording frames shown in  FIG. 21 . The DC control bit is so controlled that a modulated DSV approaches 0. 
     Modulation of the data in the recording frame induces  17  modulations according to the table shown in  FIG. 22 . A frame sync signal is attached using a sync code of 30 bits as shown in  FIG. 23 . In  FIG. 23 , if data occurring after a modulation preceding a sync code is terminated with 0000 or 00, # is 1; in other cases, # is 0. 
     [BCA] 
       FIG. 24  shows an arrangement of the BCA arrangement shown in  FIG. 10 , as viewed from above an optical disc  3100 . A burst cutting area (BCA)  2402  is formed coaxially in a range from 21.3 mm radius to 22.0 mm of the optical disc  3100 . Indicated by  2403  is a center hole. In this BCA, disc intrinsic information such as a disc ID or information about a format with which the disc is compliant is stored. This information occupies 4,648 channel bits of one revolution of about 4,750 channel bits. 
     A method of modulating data recorded in the burst cutting area  2402  is illustrated in  FIG. 25 . In the present modulation method, 2 bits of data are modulated into 7 bits of data. The modulated 7 bits of data is composed of a former half of 3 bits acting as a synchronization portion and a latter half of 4 bits acting as a data portion. The synchronization portion is composed only of “010”. In the data portion, “1” is set in any one bit of the 4 bits. The other bits are set to “0”. In  FIG. 25 , if the original data is “00”, the data portion is modulated into “1000”. Similarly, the original data “01”, “10”, and “11” are modulated into data portions “0100”, “0010”, and “0001”, respectively. 
       FIG. 26  schematically shows the state in which the synchronization portion and the data portion are recorded in the burst cutting area  2402 . In this case, data “0101000” is shown. In the case of bit “1”, low-reflectivity portions are formed. These are known as BCA marks. In the case of bit “0”, these low-reflectivity portions are not formed. Variations in the disc reflectivity are almost zero. 
     The structure of data recorded in the burst cutting area  2402  is shown in  FIG. 27 . In  FIG. 27 , each row is composed of 5 bytes. The leading 1 byte of each row is a synchronization byte. The latter 4 bytes are data. 
     The first row is taken as a preamble. All are set to 00h. 
     Since the first synchronization byte is used in only the first row, the starting position of the BCA code can be detected by detecting the first synchronization byte. Alternatively, it can be detected along with 00h data following the first synchronization byte. From the 2 row to the 33rd row, the area is divided into parts each having 4 rows. From the second row to the fifth row, 16 bytes of data from user data I 0 , 0  to I 0 , 15  are arranged. Subsequently, from the sixth row to the ninth row, 16 bytes of parity C 0 , 0  to C 0 , 15  corresponding to the user data I 0 , 0  to I 0 , 15  from the second row to the fifth row are arranged. The user data from the second row to the fifth row and the parity bits from the sixth row to the ninth row together constitute one ECC block. 
     Similarly, the user data I 1 , 0  to I 1 , 15  are arranged from the 10th row to the 13th row. C 1 , 0  to C 1 , 15  are arranged from parity bits corresponding to the 14th row to the 17th row. User data I 2 , 0  to I 2 , 15  are arranged from the 18th row to the 21st row. Parity bits C 2 , 0  to C 2 , 15  corresponding to the 22nd row to the 25th row are arranged. User data I 3 , 0  to I 3 , 15  are arranged from the 26th row to the 29th row. Parity bits C 3 , 0  to C 3 , 15  corresponding to the 30th row to the 33rd row are arranged. 
     The sync bytes from the second row to the fifth row are set to SB 00 . The sync bytes from the sixth row to the ninth row are set to SB 01 . The sync bytes from the tenth row to the thirteenth row are set to SB 02 . The sync bytes from the 14th row to the 17th row are set to SB 03 . The sync bytes from the 18th row to the 21st row are set to SB 10 . The sync bytes from the 22nd row to the 25th row are set to SB  11 . The sync bytes from the 26th row to the 29th row are set to SB 12 . The sync bytes from the 30th row to the 33rd row are set to SB 13 . No data is arranged in the 34th row but only SB 32  of sync byte is arranged. Data of  FIG. 27  indicate data prior to modulation according to the modulation method of  FIG. 25 . The data amount is 166 bytes (=5 bytes×4 rows×8 sets+5 bytes+1 byte). As a result of modulation of the information, 4648 channel bits (=166×8×7/2) are obtained. 
     A specific data sequence of the sync signal of  FIG. 27  is shown in  FIG. 28 . In the example of  FIG. 28 , data is expressed as a modulated channel bit sequence. 28 channel bits of sync byte is composed of 14 channel bits of sink body and 14 channel bits of sink ID. 14 channel bits of sink body are composed of 7 channel bits of sink body  1  and 7 channel bits of sink body  2 . 14 channel bits of sink ID are composed of 7 channel bits of sink ID 1  and 7 channel bits of sink ID 2 . 
     The sink bodies are in a pattern not complying with the already described intrinsic modulation rule. That is, if the present modulation rule were followed as set forth in  FIG. 25 , the synchronization portion should be “010”. However, the synchronization portion of the sink body  2  is different from “010” but set to “001”. Therefore, the sync bytes can be identified from data. 
     The sink bodies  1  of sync bytes are all set to “010 0001”. The sink bodies  2  are set to “001 0100”. In contrast, the sink IDs have different values for different sync bytes. Consequently, the sync bytes can be identified. Since the sync bytes are different from each other in this way, they can be identified. 
     The configuration of an ECC block of a BCA code is shown in  FIG. 29 . Reed-Solomon codes of RS (248, 216, and 33) are used for the ECC. These are Reed-Solomon codes similar to the ECC blocks of  FIG. 14 . However, in the case of the ECC block of BCA code, the leading 200 bytes are fixed data, and FFh, for example, is used as shown in  FIG. 29 . 16 bytes of data following the fixed data are used as substantial BCA user data. A parity of 36 bytes is computed using the 200 bytes of fixed data and 16 bytes of BCA data. 
     Leading 200 bytes of data out of 216 bytes of data in the present invention are fixed data and not recorded on an optical disc. Similarly, only parity bits C 0  to C 15  of the leading 16 bytes out of 32 bytes of parity are recorded on the optical disc  1 . The remaining 16 bytes of parity are not recorded. During decoding, the same value is used as it is as the 200 bytes of fixed data. Furthermore, the 16 bytes of parity not recorded are decoded as lost flags. That is, out of 32 bytes of parity, the latter 16 bytes are treated as parity bytes which have been lost from their positions. Even if a half of the parity data is lost, their positions are known and so the original parity data can be decoded. 
     In this way, by using the same RS (248, 216, 33) as the ECC of user data recorded in the user data area, quite powerful error correcting capabilities can be accomplished with BCA. Furthermore, the same hardware configuration can be used and so the circuit scale can be reduced. A cost reduction can be accomplished. Furthermore, it suffices to be able to record only 32 bytes. The data capacity can be increased compared with the case where all 248 bytes are recorded. 
     The configuration of a data block in the BCA is shown in  FIG. 30 . In the present invention, four ECC blocks are recorded in a burst cutting area  2402 . The 16 bytes of data in each ECC block is composed of leading 1 byte of content code and the following 15 bytes of content data. In the content code in the BCA, 6 bits from the first bit  7  to bit  2  are used as an application ID. The last two bits consisting of bit  1  and bit  0  are used as a sequence number. 
     The optical disc recording/reproducing device can record or reproduce data only on optical discs having predetermined application IDs. For example, the device can record key information for encryption/decryption of contents which is necessary to protect contents data on discs having certain application IDs. 
     The sequence number is composed of two bits and is any one of “00”, “01”, “10”, and “11”. When the contents data of each ECC block are 14 bytes or less, their sequence numbers are set to “00”. 
     A method of storing contents data is shown next. For example, where the same contents data are stored as contents data sets for two leading ECC blocks out of four ECC blocks (in this case, the same contents data of the same application ID are written doubly), the sequence numbers of the ECC blocks are set to “00”. That is, where the same contents data are recorded, the sequence numbers of two ECC blocks are set to the same number. 
     When 24 bytes of contents data different from the application ID of the first ECC blocks are subsequently recorded in the remaining two ECC blocks, the sequence number of the first one is set to “00” and the sequence number of the second ECC block is set to “01”. That is, where sequence numbers are used over plural ECC blocks, serial numbers are stored. 
     Since an application ID and a sequence number are recorded in each ECC block in this way, it is possible to judge from them in what ECC block are desired data stored or whether multiple writing is done. 
     The BCA contents code and contents data of the data block of  FIG. 30  correspond to I 0 , 0  to I 0 , 15  of the leading ECC block of  FIG. 27 . 
     Since the BCA is divided into four ECC blocks, recorded various types of data are classified according to purpose of use. Contents data are arranged so as to be located within the same ECC block and recorded on a disc. For example, contents data which facilitate identification of disc types and are useful for rapidity of setup and information about disc type, recording characteristics, version number of a standard with which the disc is compliant, type information, surface information, and the number of recording layers are stored and recorded in the same ECC block. Contents data used for copy management, manufacturer identification code, and unique number are stored and recorded in another ECC block. Unnecessary ECC computations and undesired transfer of contents data through the memory space can be prevented by recording contents data in separate blocks according to application in this way. The load on the recording/reproducing device can be reduced. 
     [Disc Recording/Reproducing Device] 
     A recording/reproducing device for recording and reproducing the optical disc for which shape, data encoding, and BCA have been described as preferable for the present invention is described by referring to  FIG. 31 .  FIG. 31  is a block diagram of the recording/reproducing device. In  FIG. 31 , indicated by  3100  is a recordable optical disc shown in  FIGS. 2 ,  3 ,  8 , and  9 . A disc motor  3101  rotates the disc  3100 . An optical pickup  3102  irradiates laser light on the disc  3100 , detects reflected light, and obtains a reproduction signal. Also, the  3102  irradiates laser light having a waveform precisely shaped during recording on the disc  3100  and makes a recording. An analog front end  3103  shapes the waveform of the signal detected by the optical pickup  3102 , generates a servo signal, and performs other processing. A demodulation processing circuit  3104  binarizes the wave shaped signal and performs decoding based on the 1-7 modulation described in encoding processing of data. Indicated by  3105  is a DRAM (Dynamic Randum Access Memory) used to temporarily store decoded data, data being corrected, input and output data, unmodulated data, and so on. Indicated by  3106  is an ECC (Error Correction Circuit) that provides error correction of already decoded data temporarily stored in the DRAM  3105  during reproduction processing. During recording processing, the ECC adds error correcting codes to the input data temporarily stored in the DRAM  3105 . Indicated by  3107  is an interface circuit that causes the data temporarily stored in the DRAM  105  to be output from an output terminal  3114 , stores the input data from an input terminal  3113  in the DRAM  3105 , causes the BCA related information stored in the DRAM  3105  to be output from an output terminal  3115 , and implements other interface processing. Note that  3113  and  3115  can be made common. Furthermore,  3113 ,  3114 , and  3115  can be made common by using bidirectionality. A modulator circuit  3108  modulates data read from the DRAM  3105  based on the 1-7 modulation described in the encoding processing of data during recording, and supplies the modulated data to an LDD (Laser Diode Driver)  3109 . During recording, the LDD  3109  supplies a recording waveform appropriate for recording of the modulated data to the optical pickup  3102 . The optical pickup  3102  emits according to the recording waveform and makes a recording. A BCA decoder  3110  performs decoding of the BCA data blocks recorded according to the presence and absence of low reflectivity as described in [BCA] during the reproduction of the BCA. 
     When the power supply is turned on or the optical disc  3100  is inserted, the recording/reproducing device executes setup processing included in recording instructions and reproduction instructions from a host controller. First, laser light is irradiated on the disc  3100 . The reflectivity of the disc or the distance between the cover layer and the recording layer is obtained by making use of light returning from the disc  3100 . The type of the disc is identified roughly. Then, the disc  3100  is rotated counterclockwise using the disc motor  3101  to move the optical pickup  3102  from a radial position of 21.3 mm to 22.0 mm in the BCA. Then, based on the results regarding the type, parameters regarding the laser power and focus servo are initialized. BCA data are reproduced while performing focus servo control. The type of the disc, compatibility, playability, or recordability is determined from the disc type contained in the reproduced BCA data, recording characteristics (such as ROM, recordable, or rewritable), the presence or absence of recordability and playability, type information indicating whether the disc is single-sided or double-sided, surface information indicating whether the surface is A or B, the number of recording layers, the direction in which the data area is recorded and reproduced, and the presence or absence of a disc cartridge. Various kinds of disc management information recorded in the Inner Zones  1002 ,  1014  and Outer Zones  1004 ,  1016  are read out, and preparations are made for recording instructions and reproduction instructions from a host controller. When the optical disc detected by the recording/reproducing device has no cartridge in spite of the fact that disc cartridge information read from the BCA indicates that there is a cartridge, there is the possibility that hands grease, smudges, or the like adheres to the recording surface or the recording surface is scratched and thus the recording quality is not assured sufficiently. Hence, the disc can be used as a disc having only reading compatibility. 
     In a system for managing file management information about file data recorded in the Data Zones  1003  and  1015  of the disc by means of the HDD within the host controller, the host controller attempts to achieve consistency between the disc and the file management information using disc ID (manufacturer identification code) read from the recording/reproducing device, identification number (individual identification number), and surface information. When the recording/reproducing device can read file data from both surfaces without involving ejection or reinsertion of the optical disc, it is easy to generate and manage file management information that takes the single disc as one logical volume, from type information, surface information, and layer information on both surfaces, irrespective of whether the disc is single-sided or double-sided. 
     Then, an optical disc and recording/reproducing device therefor that is a second embodiment of the present application is described based on the first embodiment and by referring to  FIGS. 32 ,  33 , and  36 . 
     Embodiment 2 is an embodiment in a case where surface A has the same recording layer structure as the Blu-ray Disc (Trademark) and surface B has a lead-in area, a data zone, and a lead-out area. Data are recorded to and reproduced from these lead-in area, data zone, and lead-out area in the direction opposite to the surface A, i.e., counterclockwise. The BCA is reproduced in the same direction as when the surface A is read, i.e., counterclockwise. 
       FIG. 32  is a recording/reproducing device for recording and reproducing data on a double-sided disc. The device has optical pickups  3102  and  3102 B for recording and reproduction over both surfaces. The device records and reproduces data on both surfaces of the disc without ejection or reinsertion of the disc. A servo circuit  3111  for spindle, focus, and tracking controls the two optical pickups  3102  and  3102 B while switching them. Input signals from the two optical pickups are switched by an analog front end  3103  at its entrance. The disc motor  3101  can rotate the disc  3100  either counterclockwise or clockwise. In other respects, this recording/reproducing device is the same as the recording/reproducing device of  FIG. 31 . 
       FIG. 33  is a recording/reproducing device having optical pickups  3102  and  3102 B for recording and reading over both surfaces and operating to record and reproduce data at the same time on both surfaces of a double-sided disc without ejection or reinsertion of the disc. All are doubled except for the disc motor  3101 , BCA decoder  3110 , CPU  3112 , DRAM  3105 , ECC  3106 , and IF  3107 . The device is so configured that it can record and reproduce data on both surfaces of the disc  3100  independently. The CPU controls recording and reproduction on the surfaces A and B at the same time. The disc motor  3101  can rotate the disc  3100  either counterclockwise or clockwise. In other respects, this device is the same as the recording/reproducing device of  FIG. 31 . In the present recording/reproducing device, BCA data from the disc  3100  are read out from one side. 
       FIG. 36  illustrates setup processing included in recording instructions and reproduction instructions from a host controller when the optical disc  3100  is inserted into the recording/reproducing device of  FIGS. 32 and 33 . It is here assumed in the present both-sided disc that both surfaces of blu-ray Discs (Trademark) are bonded together except that the spiral direction on surface B is reverse. First, laser light from the optical pickup  3102  is irradiated on the disc  3100 . Laser light from the optical pickup  3102 B is not irradiated. The reflectivity of the recording surface located on the lower side or the distance between the cover layer and the recording layer is obtained by making use of light returning from the disc  3100 , and the disc type is identified roughly. When the present disc  3100  is a Blu-ray Disc (Trademark), the disc  3100  is rotated counterclockwise using the disc motor  3101  to move the optical pickup  3102  from a radial position of 21.3 mm to 22.0 mm in the BCA. Then, parameters regarding the laser power and focus servo for the Blu-ray Disc (Trademark) are initialized. Data from the BCA are reproduced while performing focus servo control. The type of the disc, compatibility, playability, or recordability are determined from the disc type contained in the reproduced BCA data, recording characteristics (such as ROM, recordable, or rewritable), the presence or absence of recordability and/or playability, type information indicating whether the disc is single-sided or double-sided, surface information indicating whether the surface is A or B, the number of recording layers, the direction in which the data area is recorded and reproduced, and the presence or absence of a disc cartridge. When the surface information indicates that the recording surface located on the lower side is surface B, rotation of the disc  3100  is reversed from counterclockwise to clockwise, and various types of disc management information recorded in the Inner Zones  1002 ,  1014  and Outer Zones  1004 ,  1016  are read out. Preparations are made for recording instructions and reproduction instructions from the host controller. 
     When the double-sided optical disc of embodiment 1 exists in addition to the double-sided optical disc of Embodiment 2, in the recording/reproducing device of  FIG. 32 , the direction of the rotation of the disc caused by the disc motor  3101  is controlled using information about the data recording and reproduction direction in the lead-in, data zone, and lead-out area excluding the BCA area of Byte  3 . In particular, BCA data are reproduced. Disc type, compatibility, and playability or recordability are determined from information about the type of the disc contained in the BCA data, the recording characteristics (such as ROM, Recordable, or Rewritable), the presence or absence of recordability and/or playability, type information indicating whether the disc is single-sided or double-sided, surface information indicating whether the surface is A or B, the number of recording layers, the direction in which the data area is recorded and reproduced, and the presence or absence of a disc cartridge. When the direction in which the data area is recorded and reproduced is clockwise, the rotation of the disc  3100  is reversed from counterclockwise to clockwise. Various kinds of disc management information recorded in the Inner Zones  1002 ,  1014  and in the Outer Zones  1004  and  1016  are read out, and preparations are made for recording instructions and reproduction instructions from the host controller. 
     An optical disc and recording/reproducing device therefor that is a third embodiment of the present application is next described based on the first and second embodiments. 
     Embodiment 3 is an embodiment in a case where surface A has the same recording layer structure as the Blu-ray Disc (Trademark) but surface B has lead-in, data zone, and lead-out area of data which are recorded and reproduced in the reverse direction to the surface A, i.e., clockwise, and where the BCA reading direction is reverse to the surface A, i.e., clockwise. 
     When the present optical disc is played by the recording/reproducing device of  FIG. 32  or  FIG. 33 , the direction in which the BCA is read needs to be detected during reading of the BCA data when setup processing is performed. In the present embodiment, the spindle motor  3101  is rotated in the default direction of rotation of the recording/reproducing device (counterclockwise in this example), and laser light from the optical pickup  3102  is irradiated. The BCA is reproduced. As a result, if the BCA cannot be detected or cannot be decoded correctly, it is determined that there are errors due to failure of detection of the modulation pattern of majority bit data, for example, of  FIG. 25 , that there are errors in LDC coding correction of the BCA data based on  FIG. 29 , and that the direction in which the BCA is reproduced is reverse. The laser light from the optical pickup  3102 B is irradiated, and the rotation of the spindle motor  3101  is reversed to clockwise. The BCA data are again reproduced. The BCA data are reproduced. The disc type, compatibility, playability, or recordability are determined from the information contained in the read BCA data, i.e., information about the disc type, recording characteristics (such as ROM, Recordable, or Rewritable), the presence or absence of recordability and/or playability, type information indicating whether the disc is single-sided or double-sided, surface information indicating whether the surface is A or B, the number of recording layers, the direction in which the data area is recorded and reproduced, and the presence or absence of a disc cartridge. Various types of disc management information recorded in the Inner Zones  1002 ,  1014  and in the Outer Zones  1004 ,  1016  are read out. Preparations are made for recording instructions and reproduction instructions from the host controller. 
     An optical disc and recording/reproducing device therefor being a fourth embodiment of the present application is next described by referring to  FIGS. 6 and 7 , based on the first through third embodiments. 
     Embodiment 4 is an embodiment in a case where surface A has the same recording layer structure as the Blu-ray Disc (Trademark) in the same way as in embodiment 3 but surface B has lead-in area, data zone, and lead-out which are recorded and reproduced in the direction reverse to surface A, i.e., clockwise and where the BCA reproduction direction is reverse to surface A, i.e., clockwise. 
       FIGS. 6 and 7  show the shape of the marks of the BCA in the present embodiment. Indicated by  602  is a marker indicative of the direction in which the BCA is reproduced.  601  indicates that the present recording surface is reproduced counterclockwise.  701  indicates that the present recording surface is reproduced clockwise. The present marker is composed of a plurality of BCA marks. Each mark has a width that is double the normal BCA marks shown in  FIG. 26 , and is placed at the head of the array of other BCA data. When the present optical disc is reproduced by the recording/reproducing device of  FIG. 32  or  FIG. 33 , the present marker is used for detection of the direction in which the BCA is reproduced during reading of the BCA data when setup processing is performed. In the present embodiment, the spindle motor  3101  is rotated in the default direction of rotation of the recording/reproducing device (counterclockwise in this example). The laser light from the optical pickup  3102  is irradiated, and the BCA is reproduced. When the marker indicating the direction in which the BCA is reproduced cannot be detected at the head of the array of the other BCA data, it is judged that the BCA reproduction direction is reverse. The laser light from the optical pickup  3102 B is irradiated. Rotation of the spindle motor  3101  is reversed to clockwise. The BCA data are again reproduced. The data in the BCA are reproduced. The disc type, compatibility, playability, or recordability are determined from the information contained in the reproduced BCA data, i.e., disc type, recording characteristics (such as ROM, Recordable, or Rewritable), the presence or absence of recordability and/or playability, type information indicating whether the disc is single-sided or double-sided, surface information indicating whether the surface is A or B, the number of recording layers, the direction in which the data area is recorded and reproduced, and the presence or absence of a disc cartridge. Various types of disc management information recorded in the Inner Zones  1002 ,  1014  and in the Outer Zones  1004 ,  1016  are read out. Preparations are made for recording instructions and reproduction instructions from the host controller. 
     REFERENCE SIGNS LIST 
       3100 : optical disc;  3101 : disc motor;  3102 : optical pickup;  3103 : analog front end;  3104 : demodulation circuit;  3105 : DRAM;  3106 : ECC;  3107 : interface circuit;  3108 : modulator circuit;  3109 : LDD;  3110 : BCA decoder;  311 : servo circuit;  3112 : CPU