JP4279788B2 - Control device, control method, and information access device - Google Patents

Description

  The present invention relates to a control device, a control method, and an information access device.

  2. Description of the Related Art In recent years, with the progress of technology for increasing the capacity of optical discs, next-generation optical discs have been proposed and are expected as optical discs capable of recording high-definition video data distributed by digital broadcasting.

  Due to the characteristics of an optical disc video recorder that records digital broadcasts, there are some that record video data using a dedicated file system for digital broadcast recording instead of using a general-purpose file system. (For example, refer to Patent Document 1).

As a general-purpose file system, ECMA167 is known. Here, ECMA 167 is the same as ISO / IEC 13346 international standard.
(For example, refer nonpatent literature 1).
Japanese Patent Laid-Open No. 2003-168266 (FIG. 15) Standard ECMA-167 3rd Edition-June 1997: ECMA-Standardizing Information and Communication Systems <http: //www.ECMA-Standardizing Information and Communication Systems <http: // www. ecma. ch>

  There is a possibility that data is recorded on the optical disc using a mixture of two different file systems. For example, even if data is recorded on a next-generation optical disc using a dedicated file system for digital broadcast recording, the optical disc may be recorded with a general-purpose file system that is widely spread in the market. Because. Actually, there is a possibility that a next-generation optical disk may be used in two usage methods: an optical disk used in a dedicated file system and an optical disk used in a general-purpose file system. If the two different file systems cannot be recognized correctly, the recording / reproducing device may malfunction.

  For example, when a disk image file of an optical disk used in a dedicated file system is recorded by using a general-purpose file system, what is supposed to be accessed by the general-purpose file system is accessed by the dedicated file system. There is a possibility that data may be destroyed by unintended instructions. More specifically, when the area used in the dedicated file system is an area from LSN 512 to LSN (n-512) (LSN is a logical sector number, n is the last LSN), this area is a general-purpose file system. Since it is within the partition to be used, data is read from the area from LSN 512 to LSN (n-512) of the optical disc recorded with the dedicated file system, and the read data is formatted as a single file with a general-purpose file system. According to the standard, it is allowed to record at the same position on another optical disc. When this disk is inserted into a consumer device that supports only a dedicated file system, the disk is accessed using the dedicated file system.

  It is an object of the present invention to provide a control device, a control method, and an information access device that can avoid such an unintended malfunction.

  A control device according to the present invention is a control device that controls a drive device to access a rewritable information recording medium using a first file system, and the information recording medium is capable of recording data. A first file system space that can be used to record data using the first file system; and a second different from the first file system. A second file system space that can be used to record data using a file system is defined; the first file system space is included in the second file system space; First determination means for determining whether or not the information recording medium is not allowed in the second file system; When it is determined that the information recording medium does not allow the second file system, there is a possibility that valid data in the first file system is recorded in the first file system space. A second determination means for determining that the object is present, thereby achieving the object.

  What is not permitted in the second file system is permitted in the second file system in a predetermined first area located in the second file system space and outside the first file system space. Recording the predetermined data other than the predetermined data, and the first determination unit determines whether the data read from the predetermined first area matches the predetermined data. Thus, it may be determined whether or not the information recording medium is not allowed in the second file system.

  When it is determined that the data read from the predetermined first area matches the predetermined data, the control device extracts data from the predetermined second area located in the first file system space. The information processing apparatus may further include reading means for reading and third determination means for determining whether or not the data read from the predetermined second area matches data permitted in the first file system.

  The control device executes processing according to the first file system when it is determined that the data read from the predetermined second area matches data allowed in the first file system. Means may further be provided.

  When it is determined that the data read from the predetermined first area does not match the predetermined data, the second determination unit determines that valid data in the first file system is the first file system. It may be determined that it is not recorded in the space.

  The predetermined data may be null data.

  The second file system is a file system compliant with ECMA 167, and the predetermined first area includes an area for recording an initial descriptor for volume recognition and an area for recording volume structure information. It may be any of the areas for recording the start volume descriptor pointer shown.

  What is not permitted in the second file system is that a replacement area is not allocated in advance in the data recording area, and the first determination means determines whether or not the size of the replacement area is zero. By determining, it may be determined whether or not the information recording medium is not allowed in the second file system.

  The control device, when it is determined that a replacement area is not pre-allocated in the data recording area, a reading means for reading data from a predetermined second area located in the first file system space; The apparatus may further comprise third determination means for determining whether or not the data read from the predetermined second area matches the data allowed in the first file system.

  The control device executes processing according to the first file system when it is determined that the data read from the predetermined second area matches data allowed in the first file system. Means may further be provided.

  If it is determined that an alternative area is pre-allocated in the data recording area, the second determining means indicates that valid data in the first file system is not recorded in the first file system space. You may judge.

  A control method of the present invention is a control method for controlling a drive device to access a rewritable information recording medium using a first file system, and the information recording medium is capable of recording data. A first file system space that can be used to record data using the first file system; and a second different from the first file system. A second file system space that can be used to record data using a file system is defined, and the first file system space is included in the second file system space, and the control method includes: Determining whether the second file system is not allowed in the information recording medium; and If it is determined that the information recording medium is not allowed in the two file system, there is a possibility that valid data in the first file system may be recorded in the first file system space. Determining, thereby achieving the above objective.

  An information access device according to the present invention includes an information processing device including a drive device that accesses a rewritable information recording medium, and a control device that controls the drive device to access the information recording medium using a first file system. In the access device, the information recording medium has a data recording area capable of recording data, and the data recording area is used for recording data using the first file system. A first file system space that can be used, and a second file system space that can be used to record data using a second file system different from the first file system, wherein the first file is defined A system space is included in the second file system space, and the control device is included in the second file system. A first determination unit that determines whether or not the information recording medium is not allowed to exist in the information recording medium, and a case in which it is determined that the information recording medium is not permitted to exist in the information recording medium. Includes second determination means for determining that there is a possibility that data valid in the first file system is recorded in the first file system space, thereby achieving the above object.

  According to the present invention, when there is a possibility that data is recorded on an optical disc using a mixture of a first file system (for example, a dedicated file system) and a second file system (for example, a general-purpose file system), It is possible to prevent malfunction of the information access device that accesses the optical disc.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1. Optical Disc The optical disc used in the present invention is a rewritable optical disc. The optical disc has a data recording area in which data can be recorded. On the data recording area, in order to record data using a first file system space that can be used to record data using the first file system and a second file system different from the first file system. A second file system space that can be used is defined in advance. Further, the first file system space is included in the second file system space (that is, a part of the second file system space is equal to the first file system space).

  As the first file system, for example, BDFS can be used. BDFS is a dedicated file system for digital broadcast recording. In this case, the first file system space is an area from LSN 512 to LSN (n-512). Here, n is the last LSN. However, BDFS is only an example of the first file system. It is not intended that the first file system be limited to BDFS or any other specific dedicated file system.

  As the second file system, for example, a file system compliant with the ECMA167 standard can be used. This file system is sometimes called UDF (Universal Disc Format). UDF is a registered trademark of Optical Storage Technology Association. This file system is a general-purpose file system that can be widely used without being specialized for a specific application (for example, a computer application, a video application, etc.). In this case, the second file system space is an area from LSN0 to LSNn (that is, a volume space). Here, n is the last LSN. However, UDF is only an example of the second file system. It is not intended that the second file system be limited to UDF or other specific general purpose file systems.

  Note that a rewritable optical disk is a typical example of a rewritable information recording medium. However, it is not essential that the medium used in the present invention is a disk. A medium other than a disk is also possible. Further, it is not essential that the medium used in the present invention is a medium that can optically read and write data. A medium other than a medium that can optically read and write data (for example, a medium that can magnetically read and write data) is also possible.

2. Method for Accessing Optical Disc FIG. 1 shows an example of the procedure of a method for accessing an optical disc. Here, an example will be described in which BDFS, which is an example of a dedicated file system, is used as the first file system, and UDF, which is an example of a general-purpose file system, is used as the second file system.

  In step S101, data is read from the sector of LSN16. The LSN16 sector is located outside the file system space that can be used to record data using BDFS (ie, the first file system space) and can be used to record data using UDF. Located in the file system space (ie, the second file system space). The sector of LSN16 is the start sector of the volume recognition sequence in the ECMA167 standard.

  In step S102, it is determined whether or not the data read from the sector of the LSN 16 is null data. Here, null data is data in which the values of all bits are zero.

  Note that data to be compared with data read from the sector of the LSN 16 is not limited to null data. Instead of null data, arbitrary data other than data allowed in UDF (for example, hexadecimal FF data) can be used. Null data is only an example of data other than data that is not allowed in UDF.

  If the determination result in step S102 is “Yes”, it is determined that there is a possibility that valid data in BDFS is recorded in the first file system space. Thereafter, the process proceeds to step S111, and in steps S111 to S112, it is determined whether or not valid data in BDFS is recorded in the first file system space. If the determination result in step S102 is “No”, it is determined that valid data in BDFS is not recorded in the first file system space. Thereafter, the process proceeds to step S120, where it is determined whether there is a possibility that valid data in the UDF is recorded in the second file system space in step S120.

  In step S111, data is read from the sector of LSN 512. The LSN 512 sector is located in a file system space (ie, the first file system space) that can be used to record data using BDFS. The sector of LSN 512 is a sector indicating a read start position in BDFS.

  In step S112, whether or not the data read from the LSN 512 matches predetermined data allowed in the BDFS (for example, whether or not the BDFS identification information is included in the data read from the LSN 512). Is determined.

  If the determination result in step S112 is “Yes”, it is determined that valid data in BDFS is recorded in the first file system space. Thereafter, the process proceeds to step S113, and the process is executed according to BDFS in steps S113 to S115. If the determination result in step S112 is “No”, it is determined that valid data in BDFS is not recorded in the first file system space. Thereafter, the process ends.

  In step S113, the pointing block in the header table is read, and the loop table number indicated by the largest pointing block of the block counter is acquired.

  In step S114, the loop table corresponding to the loop table number acquired in step S113 is read, and the start sector number of the file management information area is acquired from the update block having the largest block counter value.

  In step S115, management information of a predetermined file is acquired by accessing the file management information area using the start sector number of the file management information area acquired in step S114.

  In step S120, whether or not the data read from the sector of the LSN 16 matches predetermined data allowed in the UDF (for example, the data read from the LSN 16 matches the top data of the UDF volume recognition sequence) Whether or not) is determined.

  If the determination result in step S120 is “Yes”, it is determined that there is a possibility that valid data in the UDF is recorded in the second file system space. Thereafter, the process proceeds to step S121, and it is determined in step S121 whether or not valid data in the UDF is recorded in the second file system space. If the determination result in step S120 is “No”, it is determined that valid data in the UDF is not recorded in the second file system space. Thereafter, the process ends.

  In step S121, the remaining data in the UDF volume recognition sequence is read from the sector following the sector of LSN 16, and the volume identification information is acquired. When the volume identification information is NSR03, it is recognized that valid data in the UDF is recorded in the second file system space.

  In step S122, data is read from the sector of LSN256. As a result, the position information of the volume descriptor string recorded in the start volume descriptor pointer is acquired.

  In step S123, the volume descriptor string is read from the position information acquired in step S122. Next, the partition descriptor and logical volume descriptor recorded in the volume description string are used to determine the partition (partition). Position information and position information of the file set descriptor are acquired. In the logical volume descriptor, domain identification information indicating which specification the ECMA 167 belongs to is recorded in the logical volume descriptor, and this information may be acquired as information regarding the file system specification. .

  In step S124, the file set descriptor is read using the position information acquired in step S123. As a result, the position information of the file entry of the root directory is acquired.

In step S125, the file entry of the root directory is read using the position information acquired in step S124. As a result, the location information of the root directory is acquired from this file entry. By accessing this root directory, a file identification descriptor corresponding to a predetermined file in this directory is searched.
As a result, the position information of the file entry of the predetermined file is acquired.

  In step S126, a file entry of a predetermined file is read using the position information acquired in step S125. As a result, the position information of this file is acquired.

  As described in steps S125 and S126, a desired file can be accessed by sequentially tracing the directory or file. In this flowchart, detailed access procedures for individual files are omitted.

  As described above, the data is recorded outside the file system space (that is, the first file system space) that can be used for recording the data using the first file system, and the data is recorded using the second file system. Data is read from an area located within the file system space (ie, the second file system space) that can be used for the purpose (eg, a sector of LSN16), and the data read from that area is allowed in the second file system. Whether or not there is a possibility that valid data in the first file system is recorded in the first file system space by determining whether or not the data matches predetermined data (for example, null data). Can be determined. Based on the determination result, it can be determined whether the process is executed according to the first file system or the process is executed according to the second file system. Thereby, it is possible to prevent malfunction of a device that accesses the optical disc (for example, a recording / reproducing device that performs recording or reproduction with respect to the optical disc).

  Note that, according to the ECMA167 international standard rules, file system identification information is recorded in the volume structure descriptor format in the volume recognition sequence recorded in the LSN16 sector and subsequent sectors so that the file system type can be identified. It is a rule to do. However, since a dedicated file system such as BDFS has a dedicated specification, it is difficult to assign file system identification information related to ECMA 167. For this reason, when using a dedicated file system, null data is recorded in the sector of the LSN 16. Alternatively, arbitrary data that is not allowed in the ECMA 167 file system (for example, FF data in hexadecimal) may be recorded in the LSN 16 sector instead of the null data.

  Note that volume identification information indicating that a data structure for a general-purpose file system such as UDF is recorded may be recorded in the second sector of the volume recognition column. In step S101, instead of reading data from the LSN16 sector, data is read from the LSN17 sector, and processing is performed according to the dedicated file system based on the data read from the LSN17, or processing is performed according to the general-purpose file system. You may make it determine whether to do.

  If the processes in steps S101 and S102 are interpreted as general-purpose file system processes conforming to ECMA167, the processes in steps S120 to S126 are the same as those in the conventional general-purpose file system. The difference is that a branch to the dedicated file system is provided as part of the processing of the general-purpose file system. In a device that reads data using only the dedicated file system, steps S101 and S102 are added to a series of processing steps S111 to S115 of the dedicated file system.

  In the example illustrated in FIG. 1, when the determination result in step S102 is “No”, the processing in steps S120 to S126 is executed. However, the processing ends without executing these processings. You may make it do. For example, when the device that accesses the optical disc has the capability of processing according to the first file system, but does not have the capability of processing according to the second file system, the processing in steps S120 to S126 is performed. It is effective to end the processing without executing the above. If there is no possibility that valid data in the first file system is recorded in the first file system space, there is a possibility that valid data in the second file system is recorded in the first file system space. This is because prohibiting access to the first file system space is effective to prevent malfunction of the apparatus.

  FIG. 2 shows another example of the procedure of the method for accessing the optical disc. The procedure shown in FIG. 2 aims to reduce the number of accesses to the optical disc by simplifying the processing steps. Here, an example will be described in which BDFS, which is an example of a dedicated file system, is used as the first file system, and UDF, which is an example of a general-purpose file system, is used as the second file system.

  In step S201, data is read from the sector of LSN256. The LSN 256 sector is located outside the file system space that can be used to record data using BDFS (ie, the first file system space) and can be used to record data using UDF. Located in the file system space (ie, the second file system space). The sector of LSN256 is a sector in which a start volume descriptor pointer is recorded in the ECMA167 standard.

  In step S202, it is determined whether the data read from the sector of the LSN 256 is null data. Here, null data is data in which the values of all bits are zero.

  Note that data to be compared with data read from the sector of the LSN 256 is not limited to null data. Instead of null data, arbitrary data other than data allowed in UDF (for example, hexadecimal FF data) can be used. Null data is only an example of data other than data that is not allowed in UDF.

  If the determination result in step S202 is “Yes”, it is determined that there is a possibility that data valid in BDFS is recorded in the first file system space. Thereafter, the process proceeds to step S211, and it is determined in steps S211 to S212 whether or not valid data in BDFS is recorded in the first file system space. If the determination result in step S202 is “No”, it is determined that valid data in BDFS is not recorded in the first file system space. Thereafter, the process proceeds to step S221, where it is determined whether or not valid data in the UDF is recorded in the second file system space in step S221.

  In step S221, whether or not the data read from the sector of the LSN 256 matches predetermined data allowed in the UDF (for example, the data read from the LSN 256 becomes the data of the start volume descriptor pointer of the UDF. Whether or not they match).

  If the determination result in step S221 is “Yes”, it is determined that valid data in the UDF is recorded in the second file system space. Thereafter, the process proceeds to step S222, and the process is executed according to the UDF in steps S222 to S226. If the determination result in step S221 is “No”, it is determined that valid data in the UDF is not recorded in the second file system space. Thereafter, the process ends.

  At the head of the start volume descriptor pointer, descriptor identification information, ECMA 167 version number, checksum and CRC (Cyclic Redundancy Check) information are recorded as descriptor tags. Therefore, based on these pieces of information, it can be determined whether or not the data read from the sector of the LSN 256 matches the data of the start volume descriptor pointer.

  The processing contents of steps S211 to S215 are the same as the processing contents of steps S111 to S115 described in FIG.

  The processing contents of steps S222 to S226 are the same as the processing contents of steps S122 to S126 described with reference to FIG.

  Thus, in step S202, it is determined whether the data read from the sector of the LSN 256 is null data. In step S221, the data read from the LSN 256 becomes the data of the start volume descriptor pointer of the UDF. By determining whether or not they match, it is possible to easily determine whether or not this optical disc is recorded in conformity with ECMA167. This makes it possible to omit the process of accessing the volume recognition sequence recorded in the sector of the LSN 16 and the subsequent sector.

  In step S201 in FIG. 2, data may be read from at least two of the sectors of LSN256, LSNn, and LSN (n-256). Here, n is the last LSN. In this case, in step S202, it is determined whether both of the read at least two data are null data. In step S221, at least one of the read at least two data is started. It may be determined whether the data matches the volume descriptor pointer data. This is because in ECMA 167, the start volume descriptor pointer is to be recorded in at least two of the LSN 256, n-256, and n sectors.

  As in FIG. 1, if the processing of steps S201 and S202 is interpreted as processing of a general-purpose file system compliant with ECMA167, the processing of steps S221 to S226 is the processing of the general-purpose file system. The difference from the general-purpose file system processing is that a part of the general-purpose file system processing is branched to a dedicated file system. In this way, the branch to the dedicated file system may be performed after the processing of the volume identification string. In a device that reads data using only the dedicated file system, steps S201 and S202 are added to a series of processing steps S211 to S215 of the dedicated file system.

  In the example illustrated in FIG. 2, when the determination result of step S202 is “No”, the processing of steps S221 to S226 is executed. However, the processing ends without executing these processings. You may make it do. For example, when the device that accesses the optical disc has the capability of processing according to the first file system but does not have the capability of processing according to the second file system, the processing in steps S221 to S226 is performed. It is effective to end the processing without executing the above. If there is no possibility that valid data in the first file system is recorded in the first file system space, there is a possibility that valid data in the second file system is recorded in the first file system space. This is because prohibiting access to the first file system space is effective to prevent malfunction of the apparatus.

  FIG. 3 shows another example of the procedure of the method for accessing the optical disc. The procedure shown in FIG. 3 is a procedure using a difference in size of an alternative area for the defect management mechanism. Here, an example will be described in which BDFS, which is an example of a dedicated file system, is used as the first file system, and UDF, which is an example of a general-purpose file system, is used as the second file system.

  In step S301, the size of the alternative area set on the optical disc is acquired. An optical disc having a defect management mechanism has a list for defect management in an area that is not normally accessible by the user. The drive device manages the defective sector that has been linearly replaced by recording and reproducing this list.

  In step S302, it is determined whether or not the size of the alternative area acquired in step S302 is zero.

  If the determination result in step S302 is “Yes”, it is determined that there is a possibility that valid data in BDFS is recorded in the first file system space. Thereafter, the process proceeds to step S311, and in steps S311 to S312, it is determined whether or not valid data in the BDFS is recorded in the first file system space. If the determination result in step S302 is “No”, it is determined that valid data in BDFS is not recorded in the first file system space. Thereafter, the process proceeds to step S321, and it is determined in step S321 whether or not there is a possibility that valid data in the UDF is recorded in the second file system space.

  The processing contents of steps S311 to S315 are the same as the processing contents of steps S111 to S115 described in FIG.

  The processing content of step S321 is the same as the processing content of steps S120 and S121 described in FIG. 1, and the processing content of steps S322 to S326 is the same as the processing content of steps S122 to S126, respectively.

  In this way, in step S302, it is determined whether or not the alternative area is pre-allocated on the data recording area of the optical disc by determining whether or not the size of the alternative area set on the optical disc is zero. can do. Alternatively, it is determined whether or not the alternative area is pre-allocated on the data recording area of the optical disc by any method other than the method of determining whether or not the size of the alternative area set on the optical disc is zero. You may do it.

  When the first file system employs a defect management mechanism that does not require a replacement area, and the second file system employs a defect management mechanism that requires a replacement area, the data is recorded on the data recording area of the optical disk. By determining whether or not the alternative area is allocated in advance, it is possible to determine whether the process should be executed according to the first file system or the process according to the second file system.

  In the design of consumer equipment, in order to reduce costs, the optical disk drive device and its control unit are often controlled by a dedicated interface instead of a general-purpose interface, or the CPU and recorder controlling the drive device The CPU that controls the system as a device may be the same. From the design philosophy of such consumer devices, it is not necessary to provide a defect management mechanism in the physical layer of the optical disk, so that a dedicated file system does not have a defect management mechanism (that is, the size of the alternative area is zero). Applying it does not cause performance issues. On the other hand, in a system composed of general-purpose parts such as a personal computer, the drive unit of the optical disk and its control unit are connected by a general-purpose interface. Doing so will degrade performance. For this reason, in a general-purpose file system in a general-purpose system such as a PC, defect management needs to be performed in the drive device. Therefore, the determination step in step S302 is extremely effective as a means for identifying the file system type.

  In addition, by using the steps described with reference to FIGS. 1 and 2 in combination with the steps described with reference to FIG. 3, it is possible to prevent the consumer device from malfunctioning more reliably.

  Here, a concept common to the methods shown in FIGS. 1 to 3 will be described.

  It is determined whether or not the optical disc is not allowed in the second file system (first determination step). This first determination step corresponds to step S102 in FIG. 1, step 202 in FIG. 2, and step 302 in FIG.

  Here, in the example shown in FIGS. 1 and 2, “not allowed in the second file system” means data other than data allowed in the second file system in the LSN16 sector (or LSN256 sector). This is equivalent to recording the data (for example, null data). In the example shown in FIG. 3, “not allowed in the second file system” corresponds to the fact that no alternative area is allocated in advance on the data recording area of the optical disc. However, the mode shown in FIGS. 1 to 3 is an example of “not allowed in the second file system”, and “not allowed in the second file system” is shown in FIGS. It is not intended to be limited to the embodiments shown.

  As a result of the determination in the first determination step, when it is determined that the optical disc is not allowed in the second file system (for example, the determination result in step S102 in FIG. 1 is “Yes”, or in FIG. When the determination result of step 202 is “Yes” or the determination result of step 302 of FIG. 3 is “Yes”, data valid in the first file system may be recorded in the first file system space. It is determined that there is a property (second determination step). In this case, it is determined whether or not valid data in the first file system is actually recorded in the first file system space. As a result, it can be confirmed that data valid in the second file system is not recorded in the first file system space. As a result, it is possible to prevent malfunction of the device accessing the optical disc.

  As a result of the determination in the first determination step, when it is determined that the optical disc is not allowed in the second file system (for example, the determination result in step S102 of FIG. 1 is “No” or FIG. If the determination result of step 202 is “No” or the determination result of step 302 of FIG. 3 is “No”, data valid in the first file system is not recorded in the first file system space. It is determined. In this case, it is assumed that valid data in the second file system may be recorded in the first file system space, and the process is terminated. As a result, when there is a possibility that valid data in the second file system is recorded in the first file system space, access to the first file system space can be prohibited. As a result, it is possible to prevent malfunction of the device accessing the optical disc.

3. Configuration of Apparatus for Accessing Optical Disc FIG. 4 shows an example of the configuration of an information access apparatus 400 for accessing the above-described optical disc.

  The information access device 400 is, for example, a recording / reproducing device that performs a recording operation or a reproducing operation on an optical disc.

  The information access device 400 includes a system control device 410, a drive device 420, and an interface 430 for connecting the system control device 410 and the drive device 420.

  The system control device 410 controls the operation of the drive device 420 by outputting a control signal to the drive device 420. The drive device 420 accesses the optical disc in accordance with a control signal output from the system control device 410.

  The system control device 410 includes at least a control unit 411 and a memory 412. The system control device 410 may be a personal computer, for example. The control unit 411 and the memory 412 can be implemented as an integrated circuit integrated on a single semiconductor chip. Alternatively, the control unit 411 and the memory 420 may be implemented as an integrated circuit integrated on separate semiconductor chips.

  The memory 412 stores a program that implements the procedure of the method shown in FIGS.

  The control unit 411 can be implemented by a processor such as a CPU (Central Processing Unit), for example. The control unit 411 can execute the method shown in FIGS. 1 to 3 by executing a program stored in the memory 412.

  In this way, the system control device 410 functions as a control device having means corresponding to each step of the procedure of the method shown in FIGS.

4). Data structure of the file system Next, the data structure of the file system in which the method of the present invention is applied will be described in detail.

  FIG. 5 shows the layout of the data recording area of the optical disc.

  As shown in FIG. 5A, in the data recording area 500, a lead-in area 501 is arranged on the inner circumference of the optical disc, a lead-out area 502 is arranged on the outer circumference of the single-layer disc, and different in the dual-layer disc. A lead-out region 502 is disposed on the inner periphery of the layer. A physical sector number (PSN) is assigned to each sector from the inner periphery. In the case of a single-layer disc, an alternative area 503 can be set after the lead-in area 501, and an alternative area 504 can be set before the lead-out area 502. In the dual-layer disc, although not shown, an alternative area can also be set on the outer peripheral side. An area 505 sandwiched between the alternative area 503 and the alternative area 504 is a volume space. Each sector in the volume space is given a logical sector number (LSN).

  The size of the alternative area can be changed when performing physical formatting. When the size of the alternative area is set to zero, as shown in FIG. 5B, the alternative areas 503 and 504 are not arranged. Further, as shown in FIG. 5C, only the alternative area 504 may be arranged.

  The replacement area is an area necessary for the drive device 420 to perform defect management using the linear replacement algorithm. In order to perform defect management using the linear replacement algorithm, an alternative area having a predetermined size needs to be allocated in advance on the data recording area 500 of the optical disc. If the alternative area is allocated in advance on the data recording area 500 of the optical disk, the capacity of the optical disk that can be actually used by the user is reduced. However, since the drive device 420 can continue the recording operation even if a defective sector is detected, the system control device 410 can handle the optical disc as a logical information recording medium having no defect. There is. For this reason, defect management using a linear replacement algorithm is suitable for handling an optical disc in a personal computer environment.

  On the other hand, when the size of the alternative area is set to zero, the system control device 410 needs to perform processing such as recording the data in another location when a defective sector is detected during data recording. . However, since there is no alternative area, there is an advantage that the data recording area 500 of the optical disk can be used effectively. For this reason, such a format is suitable for a dedicated system such as a consumer device.

  The size of the alternative area is recorded in the lead-in area 501 or the lead-out area 502. By recognizing the size of the alternative area when the drive device 420 loads the optical disk, the correspondence between the start address of the logical sector number and the physical sector number is recognized. Since the defect management is performed by the drive device 420, the size of the alternative area may be recorded in the defect management list.

  FIG. 6 shows an example of a volume / file structure layout defined by ECMA167.

  An area starting from LSN 16 is an area for a volume recognition sequence. In the volume recognition column, in order to indicate which standard the optical disc has been formatted in accordance with ECMA and ISO international standards, it is a rule to record volume structure identification information. In this example, an extended area head descriptor, an NSR descriptor, and an extended area end descriptor are recorded in the LSN 16 sector, the LSN 17 sector, and the LSN 18 sector, respectively, as the volume recognition sequence.

  Here, the NSR descriptor is a descriptor that includes a character string of NSR03 and indicates that a volume structure conforming to the ECMA167 standard is recorded.

  The start volume descriptor pointer is recorded in the sector of LSN256, the sector of LSNn, and the sector of LSN (n-256). Here, n is the last LSN. This start volume descriptor pointer represents position information of a volume descriptor string in which volume information is recorded.

  According to the ECMA167 standard, the start volume descriptor pointer is recorded in at least two sectors among the sector of LSN256, the sector of LSNn, and the sector of LSN (n-256). Therefore, if data is read from any one of the LSN 256 sector, the LSNn sector, and the LSN (n-256) sector, and the start volume descriptor pointer is found in the read data, the volume of the ECMA 167 Be able to access information.

  An area starting from LSN 32 is an area for a volume descriptor string. In the volume descriptor column, a basic volume descriptor, a partition descriptor, a logical volume descriptor, and a termination descriptor are recorded. The basic volume descriptor is mainly used in the case of a multi-volume, and includes basic information on the volume structure. The partition descriptor includes location information of the partition. The logical volume descriptor includes the address of the file set descriptor as information for accessing the file structure. The end descriptor indicates that valid information recorded in the volume descriptor string ends with this descriptor.

  In this example, the partition is set in an area from LSN 257 to LSN (n-257). Although not shown, a logical block number (LBN) is assigned to each sector of the partition, and information on the file structure recorded in the partition is specified using the LBN.

  A file set descriptor is recorded in a sector of LSN 257 (0 in LBN). The file set descriptor includes location information of the file entry of the root directory.

  A file entry of the root directory is recorded in the sector of LSN 258 (1 in LBN). In this example, since the root directory is small in size, it is recorded in the file entry. The DATA-A file entry recorded in the root directory is recorded in the sector of LSN 259 (2 for LBN), and the DATA-A file is recorded in the sector of LSN 260 (3 for LBN).

  As described above, the ECMA167 standard does not have any provisions regarding defect management. Therefore, the file system conforming to this standard is based on the premise that the drive device 420 performs defect management. Therefore, the volume file structure conforming to ECMA167 is used. When logically formatting a rewritable optical disk, it is necessary to set an alternative area in the rewritable optical disk in advance.

  FIG. 7 shows an example of the data structure layout of a dedicated file system for the purpose of recording digital broadcasts.

  Null data (data that is all zero values) is recorded in the LSN16 sector, the LSN17 sector, and the LSN18 sector. The present invention provides a method for discriminating two data structures by utilizing the difference between the layout of the data structure formatted in ECMA 167 and the data structure of the dedicated file system. In the conventional international standard, the volume structure identification information as a format identifier is recorded in an area starting from LSN 16, but the dedicated file system does not follow this rule. Therefore, in the conventional volume identification method, Differences in logical format cannot be identified. Further, null data is also recorded in the sector of LSN256, the sector of LSN (n-256), and the sector of LSNn.

  An area from LSN 512 to LSN 531 is a start information area. In this example, one header table and four loop tables # 1, # 2, # 3, and # 4 are set in succession in the start information area. The header table consists of four sectors, LSN 512, LSN 513, LSN 514, and LSN 515, and constitutes a pointing block. In order to reduce the number of times the sector is recorded in consideration of the repetitive recording characteristics of the sector, the data recorded in the pointing block is updated and recorded in order while being repeated in the order of LSN 512, LSN 513, LSN 514, and LSN 515.

  In the pointing block, a block counter and a valid loop table number are recorded. The value of the block counter increases by one every time the pointing block is updated and recorded. Therefore, the latest pointing block can be found by finding the pointing block having the maximum block counter value. In this example, the loop table is composed of four sectors, and each sector constitutes an update block.

  Similar to the pointing block, the data recorded in the update block is repeatedly updated and recorded in order from the first sector of the update block. In the example of the loop table # 1, LSN 516, LSN 517, LSN 518, and LSN 519 are repeatedly updated and recorded in the order.

  In the update block, position information of a block counter and an area for recording file management data is recorded. The value of the block counter of the update block is incremented by 1 every time it is updated and recorded in this loop table, and is used to find the latest update block.

  Here, for example, an identification character such as SPECIFIC_FS may be recorded as information indicating the dedicated file system in the pointing block and the update block. When data is read from an area starting from LSN 512, if a character string of SPECIFIC_FS is found in the read data, it is understood that the data has been formatted by the dedicated file system.

  In order to further improve the reliability of the data, start information areas are also provided in the areas from LSN (n-531) to LSN (n-512), and the position of the area where the file management data is recorded Information is recorded in two places.

  File management data and files are recorded between two start information areas. In this example, file management data is recorded in an area starting from LSN 1024, and a DATA-A file is recorded in a sector of LSN a.

  Here, in ECMA167, the file structure data can record the management information of each file in an arbitrary place on a sector basis. However, in the file management data of the dedicated file system, the file name and the file position information are stored. However, because of the table format, the data size is smaller than ECMA167. For this reason, file management information is recorded in a predetermined area.

  The reason why the data structure recorded in the start information area is hierarchically designed is to deal with defects in consideration of the physical rewrite characteristics of the sector. When the number of rewrites of the update block in the loop table increases and the sector becomes physically exhausted and cannot be rewritten, the header table is used to record the information in the new loop table and enable the new loop table. The pointing block in is updated and recorded. If the pointer to the file management data cannot be read, the user data cannot be read. Therefore, the pointer to the file management data is important data. For this reason, an information recording medium that does not support the defect management function in the drive device (an information recording medium for which no alternative area is set) needs the hierarchical data structure as described above in order to improve data reliability. become. When the drive device supports the defect management function, if there is a defect, the hierarchical data structure as described above is necessary to record the predetermined data in the substitute area set with a margin beforehand. There is no. Thus, the two types of data structures differ in the concept of defect management. For this reason, the method of the present invention for determining which file system to use according to the size of the alternative area is effective for the above two types of data structures.

  In order to simplify the description, the example in which the pointing block and the update block are each recorded as one sector has been described. However, when the physical recording unit of data is an ECC block, each is recorded as an ECC block unit. Also good.

  In addition, the number of sectors in the header table and the loop table need not be limited to four, and the number of loop tables need not be limited to four. These numbers may be determined in consideration of physical characteristics regarding repetitive recording of the information recording medium to be used.

  Note that the present invention is not limited to the rewritable information recording medium, and the effects of the present invention can be obtained by applying the present invention to a write-once type or a read-only information recording medium.

  Note that when logical formatting is performed using a dedicated file system, predetermined identification information may be recorded in the volume recognition column so as to be different from the data structure defined by ECAM167. For example, a special descriptor indicating a dedicated file system may be recorded in the LSN 16 sector. In this case, if data is read from the sector of the LSN 16 and this special descriptor is recorded, it is understood that the file is formatted by the dedicated file system.

  Note that the method described in FIG. 1 or 2 and the method described in FIG. 3 may be used in combination. This is because it is possible to identify an optical disk that is not a regular pattern, such as an optical disk formatted with ECMA 167 without setting an alternative area, or an optical disk formatted with a dedicated file system with an alternative area set.

  As described in the problem to be solved by the invention, the area used in the dedicated file system described in FIG. 7 is an area from LSN 512 to LSN (n-512), and this area is described in FIG. As described above, it is an area in a partition used in ECMA 167. For this reason, data is read from the area from LSN 512 to LSN (n-512) of the optical disk formatted by the dedicated file system, and the same position on another optical disk formatted by the general-purpose file system of ECMA167 as one file ( LSN 512 to LSN (n-512)). However, if this disc is inserted into a consumer device that supports only a dedicated file system, the dedicated file system is used for access, which may cause an unintended malfunction. For this reason, in the present invention, it is possible to check whether there is a possibility that the data structure of ECMA 167 is recorded before accessing it using a dedicated file system. Can be avoided.

  In the case where there is a possibility that data may be recorded on an optical disk using a mixture of a first file system (for example, a dedicated file system) and a second file system (for example, a general-purpose file system), the present invention The present invention is useful for providing a control device, a control method, an information access device, and the like that can prevent malfunction of an information access device to be accessed.

Flow chart showing an example of a procedure for accessing an optical disc The flowchart which shows another example of the procedure which accesses an optical disk The flowchart which shows another example of the procedure which accesses an optical disk The figure which shows the constitution of the information access device The figure which shows the layout of the data recording area of an optical disk The figure which shows the layout of the volume file structure prescribed | regulated by ECMA167 The figure which shows the layout of the data structure of the exclusive file system for the purpose of the recording of digital broadcasting

Explanation of symbols

400 Information access device 410 System control device 411 Control unit 412 Memory 420 Drive device 430 Interface 500 Data recording area 501 Lead-in area 502 Lead-out area 503, 504 Alternative area 505 Volume space

Claims (13)

A control device that controls a drive device to access a rewritable information recording medium using a first file system,
The information recording medium has a data recording area in which data can be recorded, and a first file that can be used for recording data using the first file system in the data recording area A system space and a second file system space that can be used to record data using a second file system different from the first file system are defined, and the first file system space is defined by the first file system space. 2 included in the file system space,
The controller is
First determination means for determining whether or not the information recording medium is not allowed in the second file system;
When it is determined that the information recording medium is not allowed in the second file system, there is a possibility that valid data in the first file system is recorded in the first file system space. And a second determination means for determining that there is a control device. What is not permitted in the second file system is permitted in the second file system in a predetermined first area located in the second file system space and outside the first file system space. Is to record predetermined data other than the existing data,
The first determination means determines whether the data read from the predetermined first area is not allowed in the second file system by determining whether or not the data read from the predetermined first area matches the predetermined data. The control apparatus according to claim 1, wherein it is determined whether or not the recording medium exists. A reading means for reading data from a predetermined second area located in the first file system space when it is determined that the data read from the predetermined first area matches the predetermined data;
3. The control according to claim 2, further comprising: a third determination unit configured to determine whether data read from the predetermined second area matches data permitted in the first file system. apparatus.   When it is determined that the data read from the predetermined second area matches the data allowed in the first file system, it further comprises processing means for executing processing according to the first file system. The control device according to claim 3.   When it is determined that the data read from the predetermined first area does not match the predetermined data, the second determination unit determines that valid data in the first file system is the first file system. The control device according to claim 2, wherein the control device determines that it is not recorded in a space.   The control device according to claim 2, wherein the predetermined data is null data.   The second file system is a file system compliant with ECMA 167, and the predetermined first area includes an area for recording a first descriptor for volume recognition and an area for recording volume structure information. The control device according to claim 2, wherein the control device is one of areas for recording a start volume descriptor pointer to be indicated. What is not allowed in the second file system is that a replacement area is not allocated in advance in the data recording area,
The first determination means determines whether or not the information recording medium is not allowed in the second file system by determining whether or not the size of the alternative area is zero. The control device according to claim 1. A read means for reading data from a predetermined second area located in the first file system space when it is determined that a substitute area is not pre-allocated in the data recording area;
The control according to claim 8, further comprising third determination means for determining whether data read from the predetermined second area matches data permitted in the first file system. apparatus.   When it is determined that the data read from the predetermined second area matches the data allowed in the first file system, it further comprises processing means for executing processing according to the first file system. The control device according to claim 9.   If it is determined that an alternative area is pre-allocated in the data recording area, the second determination means indicates that valid data in the first file system is not recorded in the first file system space. The control device according to claim 8, wherein the determination is made. A control method for controlling a drive device to access a rewritable information recording medium using a first file system,
The information recording medium has a data recording area in which data can be recorded, and a first file that can be used for recording data using the first file system in the data recording area A system space and a second file system space that can be used to record data using a second file system different from the first file system are defined, and the first file system space is defined by the first file system space. 2 included in the file system space,
The control method is:
Determining whether the information recording medium is not allowed in the second file system;
When it is determined that the information recording medium is not allowed in the second file system, there is a possibility that valid data in the first file system is recorded in the first file system space. A control method including the step of determining that there is. A drive device for accessing a rewritable information recording medium;
A control device for controlling the drive device to access the information recording medium using a first file system, comprising:
The information recording medium has a data recording area in which data can be recorded, and a first file that can be used for recording data using the first file system in the data recording area A system space and a second file system space that can be used to record data using a second file system different from the first file system are defined, and the first file system space is defined by the first file system space. 2 included in the file system space,
The controller is
First determination means for determining whether or not the information recording medium is not allowed in the second file system;
When it is determined that the information recording medium is not allowed in the second file system, there is a possibility that valid data in the first file system is recorded in the first file system space. An information access device comprising: a second determination unit that determines that there is.

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