JP2006107685A - Optical disk writing system, optical disk reading systems, program of them, and recording medium with this program recorded thereon - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk writing system of an optical disk and an optical disk reading system of an optical disk in which information of the disk can normally read even when a flaw, soil, etc. are stuck to the disk, and to provide a program of them and a recording medium with the program recorded thereon. <P>SOLUTION: An information recording and reproducing apparatus 2 built in and connected to a computer (PC) 1 writes data to the optical disk 3, rewrites and reads it. In writing the data in the optical disk 3, it is formatted by conforming to ISO9660 and a volume descriptor area 4 and a path table areas are written in separated areas. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical disc writing method, an optical disc reading method and a program thereof, and a recording medium on which the program is recorded.

In general, in a writable optical disk, such as a CD-R or CD-RW, writing / rewriting in units of packets is realized by formatting the entire surface of the disk or a specific session with a fixed-length packet. By writing logical format (file system) information (volume information, directory information, file entity, etc.) on a disk or session formatted in a fixed-length packet in this manner, an OS such as Windows (registered trademark) can be used. Can access data on the disk.
As a file system for a compact disc, ISO9660 and UDF (Universal Disk Format) are well known. Among these, the ISO9660 file system (ISO9660 format) has extremely high read compatibility.

  The ISO9660 format is composed of a volume descriptor set, a path table, a directory, and a file. The volume descriptor set and the path table mainly manage directory / file information, and the directory and the file hold information entities. In a normal case, the volume descriptor set, the path table, the directory, and the file are written in a continuous area.

As a recording method of an optical disk that has been subjected to the ISO 9660 format, there is a method that allows one unit such as an arbitrary file / directory specified by the user on the optical disk to be handled as read-only (Patent Document 1). .
As an example of applying ISO9660 format to a disk (or session) formatted with a fixed-length packet, an application “FileCD” manufactured by NewTech InfoSystems (NTI) is known.
JP 2004-110437 A

  On the other hand, in a compact disk, a continuous area on the disk may become unreadable due to a scratch or dust attached to the area where data is written. For example, in a disk that has been subjected to the ISO9660 format described above, if a flaw is attached to an area in which a volume descriptor set and a path table are written, these areas become unreadable. Then, the directory / file management information held in the volume descriptor set and the path table cannot be read due to a flaw. In this case, although the directory and file that are the entity of information can be read normally, the volume descriptor set and the path table that are the information management source cannot be read. Inaccessible.

  In view of the above problems, an object of the present invention is to write a volume descriptor set and a path table, which are areas for managing disk information, in a discontinuous area in an optical disk that has been subjected to the ISO 9660 format. And

In order to achieve the object, the present invention has the following features.
The invention according to claim 1 is an optical disc writing system having means for writing data to an optical disc having a writable area, and when writing an ISO9660 format in the writable area, a data volume descriptor and a path table Are distributed and written in discontinuous areas.

  According to a second aspect of the present invention, in the optical disk writing system according to the first aspect, the optical disk writing method further includes means for designating a position where the path table is written in the writable area.

  According to a third aspect of the present invention, there is provided the optical disc writing method according to the first or second aspect, further comprising selection means for selecting whether or not to distribute the data volume descriptor and the path table in a discontinuous area. It is characterized by having.

  The invention according to claim 4 is an optical disk reading system having means for reading data written on an optical disk having a writable area in the optical disk reading system, and written in the ISO 9660 format in the writable area. When reading data, if the volume descriptor of the data is read and the volume descriptor cannot be read, the data file / directory structure is built from the preset data path table, and the data is read. .

  According to a fifth aspect of the present invention, in the optical disk writing system according to the first to third aspects, the optical disk further has a session in which a fixed-length packet format and an ISO9660 format are applied to a rewritable area, Comparing means for comparing the first volume descriptor information written in advance on the optical disc with the second volume descriptor information written when data is added or deleted when data is added or deleted Furthermore, it is characterized by having.

  In the optical disk writing system according to claim 5, when the first volume descriptor information and the second volume descriptor information compared by the comparison means match in the optical disk writing system according to claim 5, The volume descriptor is not updated, and when the first volume descriptor information and the second volume descriptor information are different, the session volume descriptor is updated to the second volume descriptor. And

  The invention according to claim 7 is a program applicable to an optical disk writing apparatus having means for writing data to an optical disk having a writable area, and the volume of data is written when the ISO9660 format is written to the writable area. The descriptor and the path table are written in a discontinuous area in a distributed manner.

  According to an eighth aspect of the present invention, in the optical disc writing program according to the seventh aspect, a position for writing the path table in the writable area is designated.

  According to a ninth aspect of the present invention, in the optical disc writing program according to the seventh or eighth aspect, the data volume descriptor and the path table are selected to be distributed over discontinuous areas. .

  The invention according to claim 10 is a program applicable to an optical disc reader having means for reading data written on an optical disc having a writable area, and is written in the ISO 9660 format in the writable area. When reading data, if the volume descriptor of the data is read and the volume descriptor cannot be read, the data file / directory structure is built from the preset data path table, and the data is read. .

  According to an eleventh aspect of the present invention, in the optical disc writing program according to any one of the seventh to ninth aspects, the optical disc further has a session in which a fixed-length packet format and an ISO9660 format are applied to the rewritable area. When adding or deleting data, the first volume descriptor information written in advance on the optical disc is compared with the second volume descriptor information written when data is added or deleted. And

  According to a twelfth aspect of the present invention, in the optical disk writing program according to the eleventh aspect, if the compared first volume descriptor information and second volume descriptor information match, the volume descriptor of the session In the case where the first volume descriptor information and the second volume descriptor information are different, the session volume descriptor is updated to the second volume descriptor.

  A thirteenth aspect of the present invention is a recording medium on which the optical disc writing program according to the seventh to twelfth aspects is recorded.

  According to the present invention, a volume descriptor set and a path table can be distributed and written in discontinuous areas on an optical disk that has been subjected to the ISO9660 format. Therefore, the stored data can be read even if a scratch or a dirt is attached to the volume descriptor area of the optical disk.

[First Embodiment]
Next, an embodiment of an optical disc writing system according to the present invention will be described in detail with reference to the drawings. In the present embodiment, a CD-R will be described as an example of an optical disk. FIG. 1 is a diagram showing an outline of the configuration of an embodiment of the present invention. The information recording / reproducing apparatus 2 built in / connected to the computer (PC) 1 writes, rewrites and reads data on the optical disc 3.

  FIG. 2 is a diagram showing a data structure of a CD-R that has been subjected to a normal ISO9660 format. The volume of the CD-R is composed of a system area, a volume descriptor area 4, a path table area 5, a directory area 6 and a file area 7 in order from the top. In general, these areas are written in consecutive areas in the order of volume descriptor including basic volume descriptor → path table → directory → file.

  The 16 sectors from the first sector of the disk or the first sector from the first sector of the last session are reserved for the system as a system area. A volume descriptor area is subsequently written after the 16th sector reserved as a system area.

FIG. 3 is a diagram showing a “tree structure” in ISO9660 format.
The volume descriptor area includes a basic volume descriptor (PVD: Primary Volume Descriptor), a secondary volume descriptor (SVD), a volume partition descriptor, a startup record, and a volume descriptor set terminal. Has been written. This volume descriptor area contains information related to the volume, that is, the name of the volume and creator, link information to the path table area and root directory area (the top directory of the directory area) (area address (position) and area Etc.) is written.

In the path table area, link information (area address and area range) to each directory area including the root directory area is written. In each directory area, sub-directory areas existing under the respective directories and link information (address and length) to file entities are written.
In the ISO9660 file system, a “tree structure” of directory files is realized by such a data structure.

  As described above, in the ISO9660 format, data is normally written in a continuous area in the order of volume descriptor → path table → directory → file. When scratches or the like are attached in the vicinity of the volume descriptor set area of the CD-R written in this way, there is a very high possibility that the scratches will affect not only the volume descriptor but also the path table. This is because the volume descriptor and the path table are generally adjacent to each other. If both the volume descriptor and the path table cannot be read, the link to the root directory is broken, and as a result, the means for accessing the directory and file is broken.

Therefore, in the optical disk writing method according to the present embodiment, a file system structure is constructed in which an area in which a volume descriptor is written and an area in which a path table is written are distributed, and written into a CD-R.
FIG. 4 is a diagram showing a data structure of a CD-R that has been subjected to the ISO9660 format in the present embodiment. In the present embodiment, writing is performed in the order of volume descriptor → directory → file → path table, not in the order of normal volume descriptor → path table → directory → file.

  First, the 16th sector from the start sector (LBA: Logical Block Address) is written as the system area. The volume descriptor area (PVD, SVD, etc.) is first written after the 16th sector. Next, the path table area is written at a position away from the position where the volume descriptor area is written. Because the volume descriptor that manages the directory file information is separated from the path table, the management information of the other directory file even if a flaw is attached near the area of the volume descriptor set Directory / file information can be obtained from the path table holding

  For a CD-R formatted in a fixed length packet, the information of the path table can be directly written in an arbitrary area. Further, when additional writing is performed on a CD-R such as a Track At Once method, the unused area (A) is padded with zero data or the like.

  It is also possible to specify the position where the path table is written. The position where the path table is written may be designated in advance by a user who uses the CD-R or application software on the PC 1.

  FIG. 5 is a diagram illustrating a case where a position for writing a path table on the CD-R is designated in the present embodiment. In FIG. 5, the write position of the designated path table area is LBA = N. When the writing position of the path table area is designated by the application software, it may be saved as a file or the like on a hard disk built in or connected to the PC 1. In this case, LBA = N is set in the “link information to the path table area” included in the volume descriptor area.

  In addition, for a CD-R formatted in a fixed-length packet, the path table information can be directly written in LBA = N. Furthermore, when additional writing is performed on a CD-R such as a track at once method, the unused areas (B) and (C) are padded with zero data or the like.

In the ISO9660 format, data is normally written in a continuous area in the order of volume descriptor → path table → directory → file. Therefore, when reading the directory / file information, the volume descriptor, the path table, the directory, and the file are normally read in this order.
On the other hand, as described above, in the present embodiment, the volume descriptor and the path table can be written at different positions in order to improve the recoverability of the directory / file structure when data cannot be read. However, when reading data, if the volume descriptor and the path table are written at positions separated from each other, the seek distance becomes long, and as a result, it takes time to read the data.

  Therefore, in this embodiment, it is also possible to select whether to write the path table in an area away from the volume descriptor or in an adjacent area as in the past. In this case, the user who uses the CD-R or the application software on the PC 1 can select in advance whether to write in an area away from the volume descriptor or in an adjacent area. In the present embodiment, an operation of writing the path table in an area away from the volume descriptor or in an adjacent area will be described using the flowchart of FIG.

  First, a directory file to which data is written is selected (step S1). Next, information on the selected directory / file is constructed, and path table information is constructed from the directory / file information (step S2). After the path table information is constructed, it is selected whether or not to write the path table adjacent to the volume descriptor (step S3). When the path table is distributed to the volume descriptor (written at a distant position) (step S3 / Yes), the position (N) for writing the path table is designated (step S4). Next, after designating the position (N) for writing the path table, volume descriptor information is constructed (step S5). At this time, the writing position (N) of the path table is set at the same time. Finally, data is written based on the constructed information (step S6). The path table is written at the set write position (N).

  If the path table is written adjacent to the volume descriptor (step S3 / No), then the volume descriptor information is constructed (step S7). At this time, a position adjacent to the volume descriptor is set as the write position of the path table. Finally, data is written based on the constructed information (step S8). The path table is written at a position adjacent to the volume descriptor (immediately after the volume descriptor).

In this embodiment, when the write position of the path table is selected to be written in an area away from the volume descriptor, even if the volume descriptor is damaged, the directory / file information is read from the path table. Obtainable. Therefore, the recoverability of the directory / file structure when data cannot be read is improved.
Further, when the write position of the path table is selected to be written in an area adjacent to the volume descriptor, the data read time is the same as the read time of a general CD-R subjected to the ISO9660 format.
Therefore, the user can select whether to give priority to the possibility of restoration when data cannot be read or to give priority to the access speed to data at the time of normal data reading.

  In addition, in the present embodiment, even when one of the volume descriptor and the path table actually becomes unreadable due to scratches, dirt, an error, or the like, the other can be read. The directory file structure can be restored from the area, and the directory file entity can be accessed.

  When reading a CD-R in which data has already been written, the volume descriptor written in the 16th sector from the start sector of the last session on the disk is first read as defined by the ISO9660 standard. . If this sector can be read correctly, the read information will contain the start position information of the path table area and the start position information of the root directory area. Can be accessed.

  However, if the volume descriptor area cannot be read correctly due to scratches, dirt, errors, etc., the write position information of the path table area specified in advance by the user or application on the PC 1 is acquired when writing the data. Read the path table. Since the path table includes location information of the root directory area, it is possible to access the file / directory structure by reading and following this information. The operation of accessing the directory / file structure when the volume descriptor cannot be read in this embodiment will be described with reference to the flowchart of FIG.

  First, the volume descriptor written in the CD-R is read (step S11). If the volume descriptor cannot be read correctly (step S12 / No), the writing position information in the path table designated in advance by the user or the application on the PC 1 is acquired when data is written to the CD-R (step S12 / No). Step S13). Next, the path table is accessed from the acquired position information of the path table, and the information of the path table is read (step S14). Since the path table includes location information of the root directory, etc., the root directory is read from here (step S15). Thereafter, the directory information is read as appropriate to construct the directory / file structure (step S16).

  On the other hand, when the volume descriptor is read correctly (step S12 / Yes), the write table position information is acquired from the volume descriptor information (step S17), and the path table information is read (step S14). become.

  Note that the writing position information of the path table is acquired from, for example, a value input by the user, or is acquired from a value stored in a hard disk built in and connected to the PC 1 by an application on the PC 1 when writing the path table. There are ways to do it.

[Second Embodiment]
Next, an embodiment of an optical disc writing method for a rewritable optical disc will be described. In the present embodiment, a CD-RW will be described as an example of an optical disk.

As described above, in the CD-RW, writing or rewriting is performed in packet units by formatting the entire surface of the disk or a specific session with fixed-length packets. FIG. 8 is a diagram showing a structure in which an ISO9660 format is applied to a CD-RW formatted with a fixed-length packet.
In FIG. 8, it is assumed that the entire format (one session) is a fixed-length packet of 32 sectors per packet. It is assumed that arbitrary data has already been written by the ISO9660 file system (that is, a volume descriptor already exists in the 16th sector from the first sector).

  The information included in the volume descriptor includes the above-mentioned “volume and creator name, path table area and link information to the root directory area (the top directory of the directory area) (area address (position) and area In addition to “range”, information to be included such as “volume identifier”, “volume creation date and time”, and “volume update date and time” are defined by the standard. FIG. 10 is a diagram showing information included in the basic volume descriptor (PVD). It is desirable that correct data is written in these data as appropriate.

In particular, since rewriting always occurs in an area where the writing position is defined in the standard, such as a volume descriptor, the number of rewritings is very large compared to other areas. However, the information necessary to actually access files and directories is limited.
For example, the “volume update date and time” information described above is an item that should be rewritten every time a directory / file is added / deleted, but the user who uses this CD-RW. If this item is not used depending on the application on the PC 1 or the PC 1, there is no need to rewrite.

  In a rewritable optical disk such as a CD-RW, the life of the optical disk itself decreases as the number of rewrites increases. That is, it is desirable that rewriting is the minimum necessary in a rewritable optical disk. In the rewritable optical disk according to the present embodiment, items to be used and required items are set in advance in the volume descriptor information by the user or an application on the PC 1 so that rewriting of the volume descriptor is minimized. Can do. This extends the life of the optical disc.

The present embodiment will be described with reference to FIG. FIG. 9 is a flowchart showing the rewriting operation of the rewritable optical disc in the present embodiment. In this example, it is assumed that the computer is operating on the PC 1 that can write and read data on the CD-RW.
First, the volume descriptor already written in the CD-RW is read and the data is held in the memory (step S21). Next, a directory file to be newly written to the CD-RW is selected (step S22). Subsequently, information on the directory / file to be written is constructed, and path table information is constructed from the directory / file information (step S23). A new volume descriptor is constructed in the memory from the constructed directory / file information and path table information (step S24). Here, the newly constructed volume descriptor is compared with the volume descriptor already written in the CD-RW (step S25). Items of volume descriptor information to be compared are set in advance by a user or an application on the PC 1. Information relating to items to be compared (for example, offset positions in the volume descriptor) may be saved as a file on the hard disk on the PC 1 or the like. As a result of this comparison, it is determined whether or not there is a difference in the volume descriptor information (step S26). If there is no difference (step S26 / Yes), the new volume descriptor information is not written, but other necessary information (path table information, directory / file information, etc.) is written to the CD-RW ( Step S27). If there is a difference (step S26 / No), all necessary information including the new volume descriptor is written to the CD-RW (step S28).

  Therefore, according to the present embodiment, only the minimum necessary information is rewritten when rewriting the CD-RW. That is, since the rewriting of the volume descriptor that is frequently rewritten can be suppressed to the minimum necessary, the life of the CD-RW is extended.

  In addition, this invention is not limited to said embodiment, A various change is possible in the range which does not deviate from the meaning. For example, in the present embodiment, each CD-R or CD-RW has been described. However, if the optical disc is capable of writing, reading, and rewriting data, for example, a hybrid having a read-only area and a rewritable area. A disk (Hybrid CD-RW) may be used.

It is a figure which shows the outline | summary of a structure of embodiment of this invention. It is a figure which shows the data structure of the optical disk in which the normal ISO9660 format was given. It is a figure which shows the "tree structure" of an ISO9660 file system. It is a figure which shows the data structure of the optical disk in which the ISO9660 format in 1st Embodiment was given. In the first embodiment, it is a diagram showing the data structure of the optical disc when the writing position of the path table in the ISO9660 format is designated. 6 is a flowchart illustrating a case of changing a writing position of a path table in the ISO9660 format in the first embodiment. 4 is a flowchart illustrating a case where data of an optical disk subjected to ISO9660 format is read in the first embodiment. FIG. 10 is a diagram illustrating a data structure of an optical disc subjected to a fixed-length packet format and an ISO9660 format in the second embodiment. 10 is a flowchart illustrating a case where volume descriptors are compared in the second embodiment. It is a figure which shows the information contained in a basic volume descriptor.

Explanation of symbols

1 Computer (PC)
2 Information recording / reproducing device 3 Optical disc 4 Volume descriptor area 5 Path table area 6 Directory area 7 File area

Claims (13)

An optical disc writing system having means for writing data to an optical disc having a writable area,
An optical disk writing system, wherein when writing an ISO9660 format in the writable area, the volume descriptor and the path table of the data are distributed and written in discontinuous areas.   2. The optical disc writing method according to claim 1, further comprising means for designating a position at which the path table is written in the writable area.   3. The optical disc writing system according to claim 1, further comprising selection means for selecting whether or not to distribute the volume descriptor and the path table of the data to discontinuous areas. An optical disc reading method having means for reading data written on an optical disc having a writable area,
When reading the data written in the ISO 9660 format in the writable area, the volume descriptor of the data is read. If the volume descriptor cannot be read, the path table of the data set in advance is read. An optical disk reading system characterized in that a file directory structure of the data is constructed and the data is read. The optical disc further has a session in which a fixed-length packet format and an ISO9660 format are provided in a rewritable area,
When adding or deleting data in the session of the optical disc, first volume descriptor information written in advance on the optical disc and second volume descriptor written along with the addition or deletion of the data 4. The optical disc writing system according to claim 1, further comprising a comparing means for comparing with information. If the first volume descriptor information and the second volume descriptor information compared by the comparison means match, the volume descriptor of the session is not updated,
The volume descriptor of the session is updated to the second volume descriptor when the first volume descriptor information is different from the second volume descriptor information. 5. An optical disc writing method according to 5. A program adaptable to an optical disc writing apparatus having means for writing data to an optical disc having a writable area,
An optical disc writing program, wherein when writing an ISO9660 format in the writable area, the volume descriptor and path table of the data are distributed and written in a discontinuous area.   8. The optical disc writing program according to claim 7, wherein a position for writing the path table in the writable area is designated.   9. The optical disc writing program according to claim 7, wherein whether or not to distribute the volume descriptor and the path table of the data to discontinuous areas is selected. A program applicable to an optical disc reader having means for reading data written on an optical disc having a writable area,
When reading the data written in the ISO 9660 format in the writable area, the volume descriptor of the data is read. If the volume descriptor cannot be read, the path table of the data set in advance is read. An optical disc reading program for building a file directory structure of the data and reading the data. The optical disc further has a session in which a fixed-length packet format and an ISO9660 format are provided in a rewritable area,
When adding or deleting data in the session of the optical disc, first volume descriptor information written in advance on the optical disc and second volume descriptor written along with the addition or deletion of the data 10. The optical disc writing program according to claim 7, wherein information is compared with information. If the compared first volume descriptor information and the second volume descriptor information match, the session volume descriptor is not updated,
The volume descriptor of the session is updated to the second volume descriptor when the first volume descriptor information is different from the second volume descriptor information. 11. An optical disc writing program according to item 11.   13. A recording medium on which the optical disc writing program according to claim 7 is recorded.

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