JP2004171739A - Recording method and recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that, defective blocks are liable to occure in an information recording medium in which the number of rewriting times is restricted, since a rewriting occurs in an area where data is deleted in the conventional recording method. <P>SOLUTION: This recording method includes: a step S3 which searches unassigned areas in an information recording area and holds unassigned area specifying information which specifies at least one unassigned area which is found by this search in a memory; a step S4 which judges whether an unassigned area which satisfies a recording request exists in at least the one unassigned area specified by unassigned area specifying information or not; and a step 5 which assigns the unassigned area as an area for recording data when the judged result of the step 4 is "Yes" and records the data in the assigned area. <P>COPYRIGHT: (C)2004,JPO

Description

  The present invention relates to a recording method and a recording apparatus for recording data on an information recording medium in which the number of times data is rewritten to the same area is limited.

  An optical disk is an information recording medium having a sector structure. In recent years, the density and capacity of optical disks have been increasing. Demands for physical attributes of optical disks are also increasing. In particular, when using an optical disc in which the number of times data is rewritten to the same area is limited, it is necessary to avoid repeatedly recording data in a specific area of the optical disc. As one method for avoiding such repeated recording of data, a sequential recording method is being studied.

  FIG. 14 is a diagram for explaining the principle of the sequential recording method.

  In the example shown in FIG. 14, the information recording area on the optical disc is divided into six areas (A1 to A6) for simplification of the description. It is assumed that one hour of video data can be recorded in each of the six areas (A1 to A6), and the number of times of rewriting (cyclability) of this optical disc is 1000 times. For example, when recording 10 Mbps (Mega Bit / Second) video data on a 27 GB (Giga Byte) optical disk, about 6 hours of video data can be recorded.

  FIG. 14A shows a recording operation of repeatedly recording one hour of video data 1000 times in the area A1. FIG. 14B shows a state in which the area A1 becomes unusable due to rewriting fatigue due to physical characteristics of the optical disc as a result of the recording operation shown in FIG. Since the area A1 becomes unusable, only 5 hours of video data can be recorded on the optical disk on which 6 hours of video data could be recorded.

  FIG. 14C shows a sequential recording operation. In the sequential recording operation, video data is recorded in each area in the order of the area A1 to the area A6, and when the recording of the video data reaches the end of the information recording area (that is, the end of the area A6), the head of the information recording area (ie, the end of the area A6). That is, the process returns to the top of the area A1), and the recording of the video data in each area is continued in the order of the area A1 to the area A6.

  FIG. 14D shows a state in which each of the areas A1 to A6 has been rewritten 167 times as a result of the sequential recording operation shown in FIG. Thus, according to the sequential recording operation, the number of rewrites is averaged over the entire information recording area, so that rewriting fatigue per area (for example, one sector) can be reduced. As a result, even if a recording operation of recording video data for one hour 1000 times is performed, the time during which video data can be recorded on the optical disk does not decrease.

A data processing apparatus records an address indicating a position at which a search for an unallocated area is started on the optical disk, and searches for an unallocated area (empty area) from the inner circumference to the outer circumference of the optical disk from the position indicated by the address. (See, for example, Patent Document 1).
JP-A-4-120634

  However, in applications for recording data having a large data size, such as audio data and video data, a large area cannot be used when rewriting is concentrated, so a recording method that minimizes rewriting concentration is required. Was. Further, in an information recording medium that supports defect management such as a linear replacement method, there is a problem that when an unusable area becomes large, a defect management list overflows and a defect management mechanism of a recording device such as a drive breaks down. In particular, in the conventional apparatus as described above, rewriting is apt to occur in an area from which data has been deleted because data deletion is not taken into consideration, and data is recorded because an ECC block is not taken into account. There is a problem that rewriting occurs in the ECC block including the end position of the written area. In addition, since a dedicated address indicating the position where the search of the unallocated area is started must be recorded on the optical disc, a file system having no such dedicated address (for example, UDF (TM) issued from OSTA) ) And other existing standard file systems).

  The present invention has been made to solve at least one of such problems.

  The recording method according to the present invention is a recording method for recording data on an information recording medium in which the number of times data is rewritten to the same area is limited, the recording method comprising: (a) searching for an unallocated area in the information recording area; And storing, in a memory, unallocated area specifying information that specifies at least one unallocated area found by the search; and (b) the at least one unallocated area specified by the unallocated area specifying information. Determining whether there is an unallocated area that satisfies the recording request in the area; and (c) determining the recording request in the at least one unallocated area specified by the unallocated area specifying information. If there is an unallocated area that satisfies, the unallocated area is allocated as an area for recording data, and the allocated area is allocated. Includes a step of recording data, the above objects can be achieved.

  The recording method includes: (d) if there is no unallocated area satisfying the recording request in the at least one unallocated area specified by the unallocated area specifying information, A return step may be further included.

  The recording method includes: (e) searching for a new file recorded in the information recording area; and (f) generating a pointer indicating a position based on the end position of the area where the new file is recorded. Further, the search for the unallocated area in the information recording area in the step (a) may be performed in a fixed direction from a position following the position indicated by the pointer.

  The data may be recorded on the information recording medium in units of ECC blocks, the ECC blocks may include a plurality of sectors, and a search for an unallocated area in the information recording area may be performed in units of ECC blocks.

  The pointer may indicate an end position of an ECC block including an end position of an area where the new file is recorded.

  The step (e) may include a step of searching a file recorded on the information recording medium for a file having the latest generation time or modification time as the new file.

  The step (e) may include a step of searching, as a new file, a file having the largest ID number assigned to the file among files recorded on the information recording medium.

  The step (e) may include a step of searching a file recorded under a specific directory for a file most recently recorded on the information recording medium as the new file.

  The step (e) may include a step of searching, as the new file, an index file that manages list information of files recorded on the information recording medium.

  (G) updating the index file when erasing data recorded on the information recording medium or formatting the information recording medium; and (h) updating the index file. Recording the file in the area allocated in step (c).

  The recording method further includes: (i) generating a pointer indicating a random position in the information recording area, wherein the search for an unallocated area in the information recording area in the step (a) is indicated by the pointer. May be performed in a certain direction from a position following the above-mentioned position.

  The search for the unallocated area in the information recording area in the step (a) may be performed in a fixed direction from the head of the information recording area.

  The recording apparatus of the present invention is a recording apparatus that records data on an information recording medium in which the number of times data is rewritten to the same area is limited, wherein the recording apparatus performs a search for an unallocated area in the information recording area, Holding means for holding, in a memory, unallocated area specifying information for specifying at least one unallocated area found by the search, and recording in the at least one unallocated area specified by the unallocated area specifying information Determining means for determining whether there is an unallocated area satisfying the request; and an unallocated area satisfying the recording request exists in the at least one unallocated area specified by the unallocated area specifying information. In this case, the unallocated area is allocated as an area for recording data, and data is recorded in the allocated area. And a recording unit, the objects can be achieved.

  The holding unit, when there is no unallocated area that satisfies the recording request in the at least one unallocated area specified by the unallocated area specifying information, an unallocated area in the information recording area. And the unallocated area specifying information for specifying at least one unallocated area found by the search may be stored in the memory.

  The recording method of the present invention is a recording method in which a search for a new unallocated area is not performed until at least one unallocated area found by the search for an unallocated area is used. Thus, it is possible to prevent rewriting of data from being concentrated in a specific area while preventing data from being rewritten in an area from which data has been deleted. In addition, by searching for an unallocated area in units of ECC blocks from the sector following the end position of the ECC block including the end position of the area where data is recorded, the data recorded on the information recording medium recorded using the ECC block can be read. Can be prevented from being rewritten to the ECC block including the end position of the area where is recorded.

  In addition, by searching for a new file and generating a pointer indicating the start position of the search for the unallocated area from information such as the file management information, a dedicated address indicating the start position of the search for the unallocated area is recorded. It is possible to implement a sequential recording method even in an existing standard file system for which no data structure is defined. When data is recorded and deleted many times, a pointer indicating a random position on the information recording medium is generated using a random number or the like, and a search for an unallocated area is performed from a position following the position indicated by the pointer. In the existing standard file system in which the data structure for recording the dedicated address indicating the position to start the search of the unallocated area is not defined, the data recording and deletion are performed in a specific area. It is possible to avoid concentrating on. In particular, when recording data with a large data size such as audio data and video data, it is possible to avoid fatigue of sector rewriting and reduce the burden on the defect management mechanism by the drive of a disk that supports defect management. it can.

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

(Embodiment 1)
FIG. 1 is a diagram for explaining an outline of a recording method according to the present invention. Using this recording method, data can be recorded in an information recording area on an information recording medium (for example, an optical disk).

  In the example shown in FIG. 1, the information recording area is divided into six areas (areas A1 to A6) for simplicity of description, and each of the areas A1 to A6 includes at least one sector. Have been. It is assumed that the sector number increases from the left side to the right side in FIG. 1 and that data is managed in sector units on the information recording medium.

  FIG. 1A shows a state where no data is recorded in the information recording area. In this state, each of the areas A1 to A6 is an unallocated area. The search for the unallocated area is performed in a certain direction (for example, from a sector having a small sector number to a sector having a large sector number) from a predetermined position (for example, the head of the information recording area). As a result, each of the areas A1 to A6 is found as an unallocated area. Unallocated area specifying information (for example, a list of identifiers of the areas A1 to A6) for specifying the area A1 to the area A6 found as the unallocated area is held in a memory (not shown). As this memory, any type of memory provided in a recording device (not shown) for recording data on an information recording medium can be used. The search for the unallocated area is performed using, for example, data having a file structure used in a file system such as UDF (the details will be described later).

  FIG. 1B shows a state in which each of the unallocated areas A1 to A6 is allocated as an area for recording data, and data is recorded in each of the allocated areas in order from a sector having a smaller sector number to a larger sector. Show. In FIG. 1, data is represented by Di (i = 1, 2, 3,...), And the subscript numbers indicate the order in which the data was recorded.

  FIG. 1C shows a state where the data D1 and D2 have been deleted from the state shown in FIG. 1B. In this state, it is assumed that a recording request "record data D7 and D8" is received. In this case, since the unallocated area specified by the unallocated area specifying information held in the memory does not remain, the search for the unallocated area is performed in a certain direction (for example, from the beginning of the information recording area) For example, the processing is performed in a direction from a sector having a small sector number to a sector having a large sector number. As a result, each of the area A1 and the area A2 is found as an unallocated area. Unallocated area specifying information (for example, a list of identifiers of the areas A1 and A2) for specifying the areas A1 and A2 discovered as unallocated areas is held in the memory. Since the data is managed as a file, the data is deleted by deleting the file from the corresponding directory. A deletion operation such as recording null data in an area where data is recorded is not performed.

  FIG. 1D shows a state in which the unallocated areas A1 and A2 are allocated as areas for recording data, and the data D7 and D8 are recorded in the allocated areas A1 and A2, respectively.

  FIG. 1E shows a state in which data D7, D3, and D5 have been deleted from the state shown in FIG. 1D. Such data deletion is performed, for example, based on an instruction from a user.

  FIG. 1F shows a case where the information recording medium is loaded on another recording device. In this case, the search for the unallocated area is performed in a predetermined direction (for example, from the beginning of the area A3 following the area A2 in which the data D8 of the newest file is recorded) (for example, from a sector having a small sector number to a sector). In the direction of the sector with the higher number). As a result, each of the area A3 and the area A5 is found as an unallocated area. Unallocated area specifying information (for example, a list of the identifiers of the areas A3 and A5) for specifying the areas A3 and A5 discovered as the unallocated areas is held in a memory (not shown). As this memory, any type of memory provided in a recording device (not shown) in which the information recording medium is newly loaded can be used.

  FIG. 1G shows a state in which the unallocated area A3 is allocated as an area for recording data, the data D9 is recorded in the allocated area A3, and then the data D4 is deleted.

  FIG. 1H shows a state in which the unallocated area A5 is allocated as an area for recording data, and the data D10 is recorded in the allocated area A5. According to the recording method of the present invention, the data D10 is not recorded in the area A4 from which the data D4 has been deleted. According to the recording method of the present invention, once the unallocated area specifying information is held in the memory, the unallocated area in the unallocated area specifying information is kept until the unallocated area specified by the unallocated area specifying information disappears. This is because the area is used. As a result, if the data is deleted after the search for the unallocated area, the data is recorded in the unallocated area found by the search in preference to the unallocated area caused by the data deletion. become.

  FIG. 1 (i) shows a state where the unallocated areas A3 and A5 found by the search shown in FIG. 1 (f) have already been used, and thus the unallocated areas are insufficient. In this case, the search for the unallocated area is performed in a fixed direction (for example, from a sector having a small sector number to a sector having a large sector number) from a predetermined position (for example, the head of the information recording area). As a result, each of the area A1 and the area A4 is found as an unallocated area. Unallocated area specifying information (for example, a list of identifiers of the areas A1 and A4) for specifying the areas A1 and A4 discovered as unallocated areas is held in the memory.

  FIG. 1 (j) shows a state in which the unallocated area A1 is allocated as an area for recording data, and the data D11 is recorded in the allocated area A1.

  FIG. 2 is a diagram for explaining the difference between the recording method of the present invention and the conventional recording method. 2A to 2C are diagrams for explaining the recording method of the present invention, and FIGS. 2D to 2F are diagrams for explaining the conventional recording method.

  FIG. 2A shows a state where the information recording medium is loaded on the recording device. Data D8, D4, and D6 are recorded in areas A1, A2, and A3, respectively. Since the file of the data D8 is the newest file, a search for an unallocated area is performed from the beginning of the area A2 following the area A1 where this file is recorded. As a result, areas A4, A5, and A6 are found as unallocated areas.

  FIG. 2B shows a state in which the files of the data D4 and D6 have been deleted from the state shown in FIG. 2A.

  In FIG. 2C, unallocated areas A4, A5, and A6 are allocated as areas for recording data, and data D9, D10, and D11 are recorded in the allocated areas A4, A5, and A6, respectively. Indicates the status.

  On the other hand, in the conventional recording method, the state in which the information recording medium is loaded on the recording device (FIG. 2D) is the same as that in FIG. The areas A2 and A3 from which the files of the data D4 and D6 have been deleted are specified as unallocated areas (FIG. 2 (e)). As a result, data D9, D10, and D11 are recorded in areas A2, A3, and A4, respectively ((f) in FIG. 2).

  In the recording method of the present invention, data is recorded while avoiding the area from which data has been deleted, whereas in the conventional recording method, data is also recorded in the area from which data has been deleted.

  According to the recording method of the present invention, a search for a new unallocated area is performed when there is no unallocated area found by the search. If the data is deleted after the search for the unallocated area, the data is recorded in the unallocated area found by the search with higher priority than the unallocated area generated by the data deletion. This makes it possible to record data while avoiding an area from which data has been deleted. As a result, the number of rewrites for the same area can be reduced.

  As described above, the concept of the recording method of the present invention applies the concept of the conventional recording method, but does not search for a new unallocated area until the unallocated area once found by the search is used up. In this respect, the recording method is different from the conventional recording method and is a new recording method.

  The recording method of storing the position of the area from which data has been deleted and not using the area from which data has been deleted until all the data has been recorded in the unallocated area in the information recording area of the information recording medium is adopted. May be adopted. According to this recording method, the same effect as the above-described recording method can be obtained.

  Next, a recording method for recording data in ECC block units including a plurality of sectors will be described. In the case of a DVD optical disk, an ECC (Error Correction Code) is provided to 16 sectors to form an ECC block. Data is recorded in units of this ECC block. As the density and capacity of optical discs increase, the number of sectors recorded at one time as ECC blocks tends to increase.

  Here, considering the ECC block is important from the viewpoint of the number of times of rewriting. This is because, in the case of a DVD disk, when data is recorded in units of sectors and ECC blocks for one ECC block, the number of rewrites becomes 16 and 1, respectively.

  FIG. 3 is a diagram for explaining a recording method when data is recorded in four consecutive ECC blocks (Ei, Ei + 1, Ei + 2, Ei + 3).

  3A and 3B show a state where data is recorded using the recording method of the present invention, and FIGS. 3C and 3D show a state where data is recorded using a conventional recording method. It shows the state where it was done.

  As shown in FIG. 3A, the last part of the data D8 is recorded to the middle of the ECC block Ei and the ECC block Ei + 1. In this case, in the recording method of the present invention, a pointer indicating the end position of the ECC block Ei + 1 (the position of the last sector of the ECC block Ei + 1) including the end position of the area where the data D8 of the new file is recorded is generated. As shown in FIG. 3B, in the recording method of the present invention, a search for an unallocated area is performed from the sector following the position indicated by the pointer. As a result, the data D9 is recorded in an area starting from the head of the ECC block Ei + 2.

  As shown in FIG. 3C, the last part of the data D8 is recorded to the middle of the ECC block Ei and the ECC block Ei + 1. In this case, in the conventional recording method, a pointer indicating the end position of the area where the data D8 of the new file is recorded is generated. As shown in FIG. 3D, in the conventional recording method, an unallocated area is searched from the sector following the position indicated by the pointer. As a result, in order to record the new data D9 in the unallocated area found by the search, the data D8 recorded in the ECC block Ei + 1 is read, and the data at the end of the read data D8 and the beginning of the data D9 are read. A new ECC block is generated from the data of the ECC block and the newly generated ECC block is recorded in the ECC block Ei + 1. Therefore, rewriting of the already recorded ECC block Ei + 1 occurs.

  As described above, according to the recording method of the present invention, the search for the unallocated area is started from the sector following the ECC block including the end position of the area in which the data was most recently recorded (that is, the search for the unallocated area is started by the ECC block). ), It is possible to prevent the rewriting of the ECC block including the end position of the area where the data is recorded. Further, in the recording method of the present invention, rewriting of the ECC block including the head or the end of the continuous area for recording data can be prevented by searching the unallocated area in ECC block units. As a result, it is possible to prevent rewriting from being concentrated on a specific area, and to distribute areas where rewriting occurs.

  FIG. 4 is a flowchart showing the procedure of the recording method of the present invention.

  First, prior to recording data, a new file is searched to generate a pointer indicating a position at which to start searching for an unallocated area (step S1). In this specification, a "new file" refers to a file most recently recorded on an information recording medium.

  Next, a pointer indicating a position based on the end position of the area where the data of the new file is recorded is generated (step S2). For example, in the case of an information recording medium on which data is recorded in ECC block units, a pointer indicating the end position of the ECC block including the end position of the area where data is recorded is generated.

  Next, a search for an unallocated area is performed in a certain direction from a position following the position indicated by the pointer. Here, the certain direction is, for example, a direction from a sector having a small sector number to a sector having a large sector number. Unallocated area specifying information for specifying at least one unallocated area found by the search is held in a memory (not shown) (step S3).

  Next, it is determined whether at least one unallocated area specified by the unallocated area specifying information is insufficient (step S4). If the determination result in step S4 is "Yes", the process proceeds to step S2, and if the determination result in step S4 is "No", the process proceeds to step S5. For example, when a recording request of “record new data Di” is received, an unused unallocated area satisfying the recording request remains in at least one unallocated area specified by the unallocated area specifying information. Is determined. If no unused unallocated area remains (that is, all of the at least one unallocated area specified by the unallocated area specifying information has already been used), the process proceeds to step S2, and the processing proceeds to step S2. If an unallocated area remains, the process proceeds to step S5.

  Next, an unallocated area is allocated as an area for recording new data Di, and new data Di is recorded in the allocated area (step S5).

  After the data recording is completed, if there is an instruction to eject the information recording medium, the process is terminated; otherwise, the process proceeds to step S4 to continue the process (step S6).

  Although this flowchart relates to a recording method, a file may be deleted or read during the recording method.

  The position where the search for the unallocated area is started is not limited to the position following the position indicated by the pointer. The position where the search for the unallocated area is started may be any position in the information recording area. For example, the position where the search for the unallocated area is started may be a fixed position of the information recording area (for example, the head of the information recording area). In this case, since it is not necessary to generate a pointer, steps S1 and S2 can be omitted.

  The direction in which the unallocated area is searched is not limited to the direction from the sector having the smaller sector number to the sector having the larger sector number. The direction in which the unallocated area is searched may be any direction as long as it is a fixed direction. For example, the direction in which an unallocated area is searched may be a direction from a sector having a large sector number to a sector having a small sector number.

  FIG. 5 shows an example of the configuration of the information recording / reproducing apparatus of the present invention.

  The information recording / reproducing apparatus includes a system control unit 501, an optical disk drive 503, an input unit 504 such as a mouse or a remote controller, an encoder 505 for digitally encoding AV data, and converting encoded data into video / audio signals. And a decoder 506 for performing the operations. These components are interconnected via an I / O bus 502.

  The system control unit 501 includes a file management information memory 521 that holds the file management information read from the optical disk, and information related to the unallocated area (for example, at least one unallocated area found by searching the unallocated area). An unallocated area memory 522 for storing unallocated area specifying information for specifying an area, a recording buffer memory 523 for temporarily storing data to be recorded on the optical disc, and a reproduction buffer memory for temporarily storing data read from the optical disc. 524, a file search means 511 for searching for a new file using information held in the file management information memory to generate a pointer as search start position information of an unallocated area, and a pointer generation means 512. Using the information recorded in the unallocated area memory 522 An unallocated area search unit 513 that searches for an unallocated area from a position following the position indicated by the pointer, and a deficiency that determines whether at least one unallocated area specified by the unallocated area specifying information is insufficient. It includes a judging unit 514, a data recording unit 515 for recording data in the recording buffer memory 523 on the optical disk, and a data reproducing unit 516 for reading data from the optical disk to the reproduction buffer memory 524.

  The procedure of the recording method shown in FIG. 4 is executed by, for example, the system control unit 501. For example, step S1 in FIG. 4 is executed by the file search unit 511, step S2 in FIG. 4 is executed by the pointer generation unit 512, and step S3 in FIG. 4 is executed by the unallocated area search unit 513 (not The allocated area specifying information is held in the unallocated area memory 522), step S4 in FIG. 4 is executed by the shortage determination unit 514, and step S5 in FIG. 4 is executed by the data recording unit 515. The system control unit 501 can be realized by, for example, a microprocessor including a control program and an operation memory.

  Video and audio signals are input to the encoder 505 from a tuner 531 such as a TV. The signal converted by the decoder 506 can be reproduced on the TV 532.

  Hereinafter, a method for searching for a new file will be described.

  FIG. 6 shows an example of the structure of a file recorded on the information recording medium. In FIG. 6, an ellipse indicates a directory, and a rectangle indicates a file.

  In the example shown in FIG. 6, five files are recorded under the Video directory. The file having the extension of MPG is a real-time file compressed by the MPEG method. A file with an extension of IFO is a control file in which control information such as reproduction time information of a real-time file is recorded. The control file may also record editing information indicating the playback order of the video and / or audio recorded in the real-time file. The file having the extension IDX is an index file for managing list information of files recorded under the Video directory. The index file has the file name of the file recorded under the Video directory and its attribute information. By reading the index file first, a specific application such as video recording can obtain a list of files to be handled and attribute information thereof.

  In the example shown in FIG. 6, four files are recorded under the Archive directory. The files recorded under the Archive directory are general files. For example, a file whose extension is DOC is a document file.

  The volume structure and the file structure formatted in UDF are based on the ISO / IEC13346 standard.

  FIG. 7 shows the data structure of the file structure shown in FIG. 6 according to the format of the ISO / IEC13346 standard. In FIG. 7, FE indicates a file entry (File Entry), and FID indicates a file identification descriptor (File Identifier Descriptor).

  The volume structure 701 is for recording volume management information for logically handling an information recording medium, and is a space indicating an unallocated area in an information recording area (for example, a partition) set in a volume space. It has the position information of the bitmap 704 and the position information of the file set descriptor that manages the root directory. However, for simplicity of illustration, the file set descriptor is omitted in FIG.

  The space bit map 704 expresses, in bits, whether or not the sector is allocated for recording of predetermined data in units of a sector. The search for the unallocated area is performed by searching the space bitmap 704. When the space bitmap is not recorded, the search for the unallocated area can be performed by searching all the information indicating the recording position of the file recorded on the optical disk.

  In the directory, a file identification descriptor is registered for each file or directory included in the directory. The file identification descriptor includes the file name or directory name and the position information of the corresponding file entry. Attribute information such as the recording position of the data of the file or the directory and the modification time and the generation time are recorded as a file entry.

  The root directory 703 is managed by a file entry 702. Position information of a file entry in the Video directory or the Archive directory is managed by a file identification descriptor in the root directory 703. The position information of the Video directory is managed by a file entry 711, and the position information of the Archive directory is managed by a file entry 721.

  VIDEO. Information indicating the recording position of the file IDX is managed by the file entry 713. The file entry 713 is managed by a file identification descriptor in the video directory 712. Similarly, the file entries 714, 715, 716, 717 are managed by the file identification descriptor in the video directory 712.

  The file entries 723 to 726 of the files registered in the Archive directory are managed by the file identification descriptor in the directory 722.

  As described above, by recording the file entry and the directory while associating them with each other, the structure of the file shown in FIG. 6 can be managed. Note that a file entry is recorded in one sector, and a directory can be recorded in one sector if the number of file identification descriptors registered therebelow is small.

  Searching for a new file recorded on the information recording medium is achieved, for example, by tracing all file entries and directories and finding the newest file entry with the file modification time. As described above, using the file entry and the directory, the file with the latest modification time of the file can be searched for as a new file. As described above, by using the file management information, it is not necessary to record the pointer on the information recording medium, and a sequential recording method is implemented using a standard file system having no place to store the pointer. Becomes possible. As information for determining whether a file is a new file, a file generation time may be used instead of a file modification time. In this case, the file having the latest generation time may be searched as a new file. Alternatively, when a unique ID number (ID information) assigned to a file is incremented each time a file is newly generated, the file having the largest ID number (ID information) assigned to the file is determined. You may make it search as a new file.

  Next, a description will be given of a method of searching for a new file when the number of files recorded on the information recording medium is large and it is difficult to search for file entries of all files.

  In the case of the UDF format, the unique ID of the file is recorded not only in the file entry but also in the file identification descriptor. When searching for a new file, instead of tracing to the file entry of each file, tracing only the directory, searching for the file managed by the file identification descriptor with the largest unique ID, and searching for the pointer from the recording position information of this file Generate In this search method, even if the number of files increases, the search range decreases, and the search time for a new file can be shortened. For example, in the example shown in FIG. 7, instead of tracing all file entries, a new file can be searched by tracing to the Video directory 712 and the Archive directory 722.

  Further, when it takes a long time to search a directory due to an increase in the number of directories, a pointer may be generated by searching only files in a predetermined directory. For example, since an MPEG file is usually large in size, a directory in which the MPEG file is recorded is determined in advance, and a new file can be searched more quickly by searching only the files in this directory. In the example shown in FIG. 7, the Video directory may be determined in advance as a new file search directory.

  In the UDF format, a unique ID mapping data stream for managing the unique IDs of all files in a table format is defined, and this data stream can be traced from a file set descriptor. If this data stream is recorded, the file entry of the file indicated by the largest entry of the unique ID registered in this data stream is checked, and a pointer is generated from the recording position of the file indicated by the file entry. You may make it. According to this method, a pointer can be generated at high speed without tracing a file and a directory.

  Next, a recording method for generating a pointer to indicate a position other than the recording end position of the file and recording data on the information recording medium using the pointer will be described. If the number of times that video data recorded on the information recording medium is deleted at random is large, the pointer for searching for an unallocated area for the sequential recording method is stored in the information recording area rather than on the information recording medium. This is because rewriting to a specific area can be reduced by searching for an unallocated area from a random position.

  More specifically, in the recording method described with reference to FIG. 1, it is assumed that the state of FIG. 1A is an unused state. In this case, in the state of FIG. 1 (j), the number of times of recording data in the areas A1, A2, A3, A4, A5, and A6 is 3, 2, 2, 1, 2, and 1 times, respectively. In the area A1, the data D1 and D7 for which an erasure instruction has been given by the user are recorded, so that the number of recordings is larger than in other areas. As described above, even if sequential recording is performed, if the number of times of recording a file and the number of times of deleting a file increase, the number of times of recording data for each area will be different.

  FIG. 8 is a diagram for explaining a recording method of generating a pointer indicating a position other than the recording end position of the file and recording data on the information recording medium using the pointer.

  FIG. 8A shows a search for an unallocated area performed when the information recording medium in the state of FIG. 1H is loaded on another recording apparatus. In this case, the search for the unallocated area is not performed from the end of the area A5 or from the beginning of the information recording area, but a pointer indicating an arbitrary position in the information recording area is generated. A search for the allocated area is performed. Here, the “arbitrary position” means a position that is randomly determined so as to be different from the previous time every time a pointer is generated.

  In the example shown in FIG. 8A, a pointer indicating the end of the area A3 is generated. In the example shown in FIG. 8B, data D11 is recorded in the searched unallocated area A4. In the state of FIG. 8B, the number of times of recording data in the areas A1, A2, A3, A4, A5, and A6 is 2, 2, 2, 2, 2, and 1, respectively. In this case, there is an effect that the number of times of recording data in the area A1 is reduced and the number of times of recording data can be dispersed throughout the information recording area.

  Note that a pointer used to search for an unallocated area can be generated using a random number based on the current time or the like.

  Note that the timing for generating the pointer used for searching the unallocated area is not limited to the time when the information recording medium is loaded. Such a pointer may be generated at an arbitrary location when a new file is generated.

  Next, a recording method using the index file of the present invention will be described. Here, since the index file is for managing the list information of files handled by a specific application such as a video recorder, the index file is updated when the application records, edits, or deletes a video clip. Is done.

  One type of usage of an information recording medium in a video camera is to record video data obtained by shooting a video with a video camera on an information recording medium, return to an office or home, and record the image data on the information recording medium. After dubbing the video data to another medium, the video data recorded on the information recording medium is deleted, and the information recording medium is reinserted into a video camera for use.

  FIG. 9 shows how the data recording area on the information recording medium changes in such a use mode.

  As shown in FIG. 9A, when the video data and its management data are recorded after the logical format, the video data D1, its control data D2, the video data D3, its control data D4, and the data of the index file are recorded. Each data is recorded on the information recording medium in the order of D5. Here, each data is the data of the file described with reference to FIG. 6, and the video data D1 and D3 are 1001. MPG, 1002. The data of the MPG file and the control data D2 and D4 are 1001. IFO, 1002. This is the data of the IFO file.

  FIG. 9B shows a state in which each file has been deleted after the video data and its control data have been dubbed to another medium. An index file VIDEO.MAN which manages a list of files recorded in the Video directory. The IDX is updated, and the updated index file is recorded in a predetermined area on the information recording medium. The predetermined area is an area found by searching for an unallocated area and is allocated as an area for recording data.

  As described above, when the information recording medium on which the updated index file is recorded is loaded on the video camera, the updated index file is the newest file. Therefore, by searching the updated index file as a new file and generating a pointer indicating a position based on the end position of the area where the new file is recorded, the end position of the area where the updated index file is recorded is obtained. , The search for the unallocated area can be started from the position following. Here, the name of the directory in which the index file is recorded (for example, the directory name “VIDEO”) is predetermined, and the name of the index file (for example, the extension name “IDX”) is also predetermined. The file system can easily find the index file by tracing the directory tree. Also, in applications where video data recorded on the information recording medium is deleted and reused, all data on the information recording medium is deleted after dubbing related data, and the index file is updated and recorded. Sequential recording can be continued while keeping the number of recordings in each area of the information recording area uniform.

  In addition, video data obtained by shooting a video with a video camera is recorded on an information recording medium, and after returning to an office or home, dubbing the video data recorded on the information recording medium to another medium, the information is recorded. Even when the recording medium is reformatted, the updated index file may be recorded in a predetermined area on the information recording medium as shown in FIG. 9B. This makes it possible to record data while avoiding use of the area from which the data has been deleted.

  As described above, the recording method of the present invention that avoids rewriting concentration when recording data having a large data size such as audio data or video data is referred to as a circular recording method.

  Note that a flash memory may be used instead of the optical disk drive 503. For example, a flash memory such as an SD card (R) has a smaller number of times of rewriting than a normal SRAM memory, and the recording method of the present invention can be applied to such a recording medium.

  FIG. 10 shows an internal configuration of a general flash memory card. The flash memory card 550 can be connected to the I / O bus 502 of the system control unit 501 through an interface such as USB and CardBus. The flash memory card 550 includes a controller 551 realized by a CPU such as a microcomputer and a memory unit 552. The memory unit 552 includes a plurality of physical blocks, and data is recorded and reproduced in the memory unit in physical block units.

  FIG. 11 shows the correspondence between the logical space of the flash memory card provided to the system control unit 501 and the physical space composed of physical blocks. In the logical space, a logical block number (Logical Block Number: LBN) is allocated, and in the physical space, a physical block number (Physical Block Number: PBN) is allocated to each physical block. Here, the size of the logical block is the same as the size of the physical block. The correspondence information between the physical blocks and the logical blocks is managed by the controller 551. The size of the logical space is set smaller in advance than the size of the physical space. Considering that the size of the additional block is a margin of the physical space, the controller 551 can allocate a logical block to an optimal block among unused erase blocks. For example, when the system control unit 501 instructs data recording three times for a logical block indicated by LBa, the controller 551 first allocates the logical block LBa to the physical block PBa and records the data. Then, data is recorded by allocating to the physical block PBb, and finally, data is recorded by allocating to the physical block PBc. In this way, three recordings can be performed without recording data in the same block. This can be achieved by setting an additional block having a size larger than the size of the logical block.

  FIG. 12 shows a correspondence relationship between a logical space and a physical space in a flash memory card when recording large data such as video data. For example, the size of the memory unit of the flash memory card is 146 MB × 7, the size of the video data to be recorded and the size of the additional block are 146 MB. For simplicity of explanation, the size of the logical block and the physical block is 146 MB. When data D1 to D6 are sequentially recorded, physical blocks PB1, PB3, PB2, PB4, PB5, and PB6 are associated with logical blocks LB1, LB2, LB3, LB4, LB5, and LB6, respectively. PB7 is an unused state and is a recordable erase block. As described above, when the size of the data to be recorded is substantially the same as the size of the additional block, the number of physical block options to which the controller 551 can assign is reduced.

  FIG. 13 shows a difference between a recording method according to the present invention and a conventional recording method in a flash memory card. FIGS. 13A, 13B, and 13C show the conventional recording method, and FIGS. 13D, 13E, and 13F show the recording method of the present invention.

  FIG. 13A shows a state in which the recording of the data D7 in the logical block LB1 is instructed to the flash memory card in the state shown in FIG. Since the physical block PB7 is in an unused state, the controller 551 assigns the logical block LB1 to the physical block PB7 and records data in this physical block. The physical block PB1 is assigned to the logical block LB1 before data is recorded, and is therefore managed by the controller 551 as an erase block after data is recorded.

  FIG. 13B shows a state in which the recording of the data D8 is further instructed in the logical block LB1. Data is recorded in the unused physical block PB1. The physical block PB1 is allocated to the logical block LB1, and the physical block PB7 is managed by the controller 551 as an erase block.

  FIG. 13C shows a state in which recording of the data D9 is further instructed in the logical block LB1. Data is recorded in the physical block PB7 in the erased state. The physical block PB7 is allocated to the logical block LB1, and the physical block PB1 is managed by the controller 551 as an erase block.

  As described above, if the control system instructs the recording in the same logical block, the controller can allocate the recording area only to the unused physical block, so that the two areas of the physical blocks PB1 and PB7 are alternated. I have to record it.

  Here, in FIG. 13A, it is assumed that the data D1, D2, and D3 are deleted before the recording of the data D7 is instructed. In this case, since it is not known that D1, D2 and D3 have been deleted in the physical space, the correspondence between the physical blocks and the logical blocks managed by the controller 551 does not change. This is because the data recorded in the flash memory is managed by a File Allocation Table (FAT) format file system, and the fact that the data has been erased is recorded in the FAT. In the normal FAT file system, an empty area is searched for from an area having a small logical block number, and new data is recorded in the empty area. For this reason, even if empty areas exist in a plurality of areas in the logical space, as shown in FIGS. 13A to 13C, recording is performed preferentially to an empty area with a small logical block number. You. Therefore, in the illustrated example, two areas (physical blocks PB1 and PB7) are recorded alternately.

  FIG. 13D shows a state in which data D1, D2, and D3 are logically deleted from the flash memory card in the state shown in FIG. 12, and data D7 is recorded in logical block LB1. The correspondence between the logical blocks and the physical blocks is the same as the state shown in FIG.

  FIG. 13E shows a state in which the data D8 is recorded in the logical block LB2. Data is recorded in the unused physical block PB1. The physical block PB1 is allocated to the logical block LB2, and the physical block PB3 is managed by the controller 551 as an erase block.

  FIG. 13F shows a state in which data D9 is further recorded in the logical block LB3. Data is recorded in the erased physical block PB3. The physical block PB3 is allocated to the logical block LB3, and the physical block PB2 is managed by the controller 551 as an erase block.

  As described with reference to FIGS. 13D to 13F, by applying sequential recording, the controller 551 can record data in the physical blocks PB7, PB1, and PB3. It is possible to avoid recording areas alternately, and to sequentially record in different areas.

  As described above, when the size of the data to be recorded is sufficiently smaller than the size of the additional block, the logical block is set to the unused physical block so that the controller in the flash memory card does not use the same physical block. , The number of rewrites does not matter much. However, if the size of the data to be recorded is not large enough or smaller than the size of the additional block, it is difficult for the controller in the flash memory card to sufficiently avoid rewriting concentration. By applying sequential recording, fatigue of a physical block due to rewriting fatigue can be reduced.

  It is apparent that the recording method of the present invention can be applied to a case where a plurality of memory units are included in a flash memory card, or a PC card including a plurality of flash memories.

  Normally, an ECC block in a flash memory is provided for each block or each sector. However, when the ECC block includes a plurality of blocks or a plurality of sectors, an ECC block including an end position of an area where a new file is recorded is provided. By searching the unallocated area from the end of the block, the number of rewriting of the ECC block can be reduced.

  As described above, the present invention has been exemplified using the preferred embodiments of the present invention, but the present invention should not be construed as being limited to these embodiments. It is understood that the scope of the present invention should be construed only by the claims. It is understood that those skilled in the art can implement an equivalent range based on the description of the present invention and common technical knowledge from the description of the specific preferred embodiments of the present invention. Patents, patent applications, and references cited herein are to be incorporated by reference in their entirety, as if the contents themselves were specifically described herein. Understood.

  According to the present invention, a search for a new unallocated area is not performed until all at least one unallocated area found by the search for the unallocated area is used. Thus, it is possible to prevent rewriting of data from being concentrated in a specific area while preventing data from being rewritten in an area from which data has been deleted. According to the present invention, even when a new unallocated area is generated by deleting a file, a search for a new unallocated area is not performed until all previously discovered unallocated areas are used. Thereby, it is possible to prevent data from being rewritten in the area where the file has been deleted. In addition, by searching for an unallocated area in units of ECC blocks from the sector following the end position of the ECC block including the end position of the area where data is recorded, the data recorded on the information recording medium recorded using the ECC block can be read. Rewriting of the ECC block at the end of the recording can be prevented. In addition, by searching the unallocated area from the sector following the end position of the recording position of the new file, sequential recording can be performed even in a file system that does not have a data structure for recording the position where the search for the unallocated area starts. A method can be implemented. Further, by searching for an unallocated area from a random position in the information recording area, it is possible to prevent rewriting from being concentrated on a specific area in an information recording medium in which data is frequently recorded and deleted. .

  Further, the recording method of the present invention can obtain the above-described effects by using an optical disk or a flash memory having a smaller number of rewritable times than a hard disk or the like. Therefore, the present invention is useful as a recording method, a recording apparatus, and the like.

Diagram for explaining the outline of a recording method according to the present invention Diagram for explaining the difference between the recording method of the present invention and the conventional recording method The figure for explaining the recording method at the time of recording data in four consecutive ECC blocks (Ei, Ei + 1, Ei + 2, Ei + 3). Flow chart showing the procedure of the recording method of the present invention FIG. 1 is a diagram showing an example of the configuration of an information recording / reproducing apparatus according to the present invention The figure which shows the example of the structure of the file recorded on the information recording medium. FIG. 6 shows a data structure of the file structure shown in FIG. 6 in accordance with the format of the ISO / IEC13346 standard. FIG. 4 is a diagram for explaining a recording method of generating a pointer indicating a position other than the recording end position of a file and recording data on an information recording medium using the pointer. Diagram for explaining recording method using index file Diagram showing the internal configuration of a typical flash memory card FIG. 4 is a diagram showing a correspondence relationship between a logical space of a flash memory card provided to a system control unit 501 and a physical space composed of physical blocks; Diagram showing correspondence between logical space and physical space in flash memory card when recording large data such as video data FIG. 4 is a diagram showing a difference between a recording method according to the present invention and a conventional recording method in a flash memory card. Diagram for explaining the principle of the conventional recording method

Explanation of reference numerals

A1 to A6 area D1 to D11 data 501 system control unit 511 file search unit 512 pointer generation unit 513 unallocated area search unit 514 shortage determination unit 503 optical disk drive 702, 711, 721, 713, 714, 715, 716, 717, 723 , 724, 725, 726 File entry 703 Root directory 712 Video directory 713 Archive directory 711 Space bitmap

Claims (14)

A recording method for recording data on an information recording medium in which the number of times data is rewritten to the same area is limited,
The recording method,
(A) performing a search for an unallocated area in the information recording area, and retaining, in a memory, unallocated area specifying information that specifies at least one unallocated area found by the search;
(B) determining whether an unallocated area satisfying a recording request exists in the at least one unallocated area specified by the unallocated area specifying information;
(C) when an unallocated area that satisfies the recording request exists in the at least one unallocated area specified by the unallocated area specifying information, an area for recording data in the unallocated area. Recording the data in the allocated area.   (D) further including returning to step (a) when there is no unallocated area satisfying the recording request in the at least one unallocated area specified by the unallocated area specifying information. The recording method according to claim 1, wherein the recording method is performed. (E) searching for a new file recorded in the information recording area;
(F) generating a pointer indicating a position based on the end position of the area where the new file is recorded.
2. The recording method according to claim 1, wherein the search for the unallocated area in the information recording area in the step (a) is performed in a fixed direction from a position following the position indicated by the pointer.   The recording according to claim 3, wherein the data is recorded on the information recording medium in units of ECC blocks, the ECC blocks include a plurality of sectors, and a search for an unallocated area in the information recording area is performed in units of ECC blocks. Method.   The recording method according to claim 3, wherein the pointer indicates an end position of an ECC block including an end position of an area where the new file is recorded.   4. The method according to claim 3, wherein the step (e) includes a step of searching a file recorded on the information recording medium for a file having the latest generation time or modification time as the new file. Recording method.   4. The method according to claim 3, wherein the step (e) includes a step of searching, as a new file, a file having the largest ID number assigned to the file among files recorded on the information recording medium. Recording method.   4. The method according to claim 3, wherein the step (e) includes a step of searching a file recorded under a specific directory for a file most recently recorded on the information recording medium as the new file. Recording method.   The recording method according to claim 3, wherein the step (e) includes a step of searching, as the new file, an index file for managing list information of files recorded on the information recording medium. (G) updating the index file when erasing data recorded on the information recording medium or formatting the information recording medium;
The recording method according to claim 9, further comprising: (h) recording the updated index file in the area allocated in step (c). (I) generating a pointer indicating a random position in the information recording area;
2. The recording method according to claim 1, wherein the search for the unallocated area in the information recording area in the step (a) is performed in a fixed direction from a position following the position indicated by the pointer.   2. The recording method according to claim 1, wherein the search for an unallocated area in the information recording area in the step (a) is performed in a fixed direction from the head of the information recording area. A recording device that records data on an information recording medium in which the number of times data is rewritten to the same area is limited,
The recording device,
Holding means for performing a search for an unallocated area in the information recording area and storing, in a memory, unallocated area specifying information for specifying at least one unallocated area found by the search;
Determining means for determining whether an unallocated area satisfying a recording request exists in the at least one unallocated area specified by the unallocated area specifying information,
When there is an unallocated area satisfying the recording request in the at least one unallocated area specified by the unallocated area specifying information, the unallocated area is allocated as an area for recording data, A recording device for recording data in the allocated area. The holding unit, when there is no unallocated area that satisfies the recording request in the at least one unallocated area specified by the unallocated area specifying information, an unallocated area in the information recording area. 14. The recording apparatus according to claim 13, wherein the search is performed, and unallocated area specifying information for specifying at least one unallocated area found by the search is held in the memory.

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