JPH01236488A - Rewritable type optical disk control system - Google Patents

Abstract

PURPOSE:To prevent the reduction of a reading speed by describing area designating information in a file entry by the peak of an area, the length of the area and a completion position for one continuous area or above. CONSTITUTION:The title system provides an optical disk 1 to store data and the control information of the data on a same medium, an optical disk control means 6 to record, reproduce and erase with a sector unit for the optical disk 1 and a file system 7 to control, in units of a file, the data with control information having a file entry 3 to identify an area to store the file in the optical disk and a non-used area list 4 to show a storable area. The area designating information in the file entry 3 in the control information is described by the peak of the area, the length of the area and the completion position for one continuous area or above. Thus, a simple area control can be executed, the file is also stored at a continuous area and therefore, the reduction of the reading speed is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical disc used for recording data, and particularly to a rewritable optical disc management system used in a data file device for a computer.

BACKGROUND ART Conventionally, rewritable magnetic storage media such as floppy disks and hard disks have been used as external storage media for computers. In recent years, optical disks with large storage capacities of several hundred megabytes or more have begun to be used as external storage media for computers. Furthermore, with the advancement of optical disc technology, the use of not only read-only and write-once optical discs but also rewritable optical discs is being considered.

As current rewritable optical disk technologies, phase change optical disks and magneto-optical disks have been developed. However, these current technologies have several problems. In particular, there are problems such as unestablished override technology, disk reliability, and slow seek times. Override technology is being developed, starting with phase-change optical discs, but it is not yet at a practical stage, and current technology requires waiting one revolution for data erasing before data can be rewritten. Processing is slow due to rewriting.

In addition, the slow seek time compared to magnetic media is a major cause of the need for a management system for optical disks that is different from that for magnetic media.

Furthermore, in terms of reliability, there remains the problem of disk deterioration, such as differences in error rates due to frequent rewriting.

Furthermore, when used as an external storage device for a computer, the rewritable property is used to take advantage of the same management method as for ordinary magnetic media. As a management method for magnetic media, for example, MS-DO3 (Microsoft's operating system) divides the media into physical blocks of a fixed size (blocks of several kilobytes called clusters), and stores area management information for each block. A management table that records the information is used to reuse unused blocks and manage the connections of discontinuous files that span multiple blocks.

Problems to be Solved by the Invention However, if such a magnetic medium management system is used for optical disks, various problems arise.For example,
As files are deleted, unused blocks become scattered within the medium. When adding a new file to a medium that is in use like this, the operating system normally searches for free blocks sequentially starting from the lowest address and records the file, so the file is divided into multiple blocks. They will be scattered within the medium. It is desirable to record continuous data on optical discs with slow seek times, and these discontinuous files require a large head movement to read the file, slowing down the reading process, making it particularly difficult to manage optical discs. It is disadvantageous.

Furthermore, when using an optical disc that cannot be overridden, it is necessary to trace and modify the file contents scattered within the medium, and processing speed is extremely slowed down because it is necessary to wait for the rotation to be erased. .

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides an optical disc that stores data and management information for the data on the same medium, and an optical disc control that performs recording, playback, and erasure on this optical disc in sector units. and a file system that manages data on a file-by-file basis using management information having a file entry for identifying an area where a file is stored in an optical disc and an unused area list indicating a storable area; The area designation information in the file entry in this management information is configured to describe the start of the area and the length or end position of the area for one or more continuous areas.

Effects In the present invention, with the above configuration, it is not necessary to manage the medium in small block units as in the management method of magnetic media.
Simple area management is possible. In addition, since files are stored in a continuous area, the file contents are not divided into small blocks and scattered on the optical disc, which prevents a drop in read speed and realizes an efficient optical disc management system. can.

Example Explanatory diagrams of this embodiment are shown in FIGS. 1 to 11.

In Figure 1, 1 is an optical disc, 2 is management information for data recorded on the optical disc 1, 3 is a file entry indicating the recording area of a file within the optical disc, and 4 is an entry that also records the storable area of the file. Used area list, 5 is a file recording area, 6 is an optical disk control means for recording, reproducing, and erasing on the optical disk 1 in units of sectors, 7 is a file system for managing the optical disk 1, and 8 is an unused area list 4. Reference numeral 9 denotes an area management unit that manages changes in file writing positions and unused areas, and 9 a file management unit that determines file storage positions based on file entries.

Figures 2 and 3 show file entry 3 in management information 2.
and an example of the recording format of the unused area list.

Reference numeral 21 in FIG. 2 is a file ID for identifying a file, and this file A is an example in which it is recorded divided into two continuous areas, areas 1 and 2. 22 designates area 1 within this area by a start address and an end address. Area 2 is similarly specified for 23 as well. Further, it is shown that the following file B is recorded in one continuous area 3. 30 in FIG. 3 is an unused area list, which is recorded for each isolated unused area. 31 records the start address, end address, and size of the unused area. The same applies to 32. An unused area can be specified only by the start address and end address, but by recording the size, it can be compared with the file size, and the unused area for writing the file can be selected quickly.

The management method of this embodiment using such management information will be explained below.

In FIG. 4, a general magnetic medium management system using a general-purpose O8 will be explained as a comparison with this embodiment. 41 in FIG. 4 is an area management table for managing physical blocks, and 42
shows a case where the medium is divided into equal physical blocks (usually several KB to about ten-odd KB), and the usage status of each block is recorded at a corresponding position in the area management table 41. In the magnetic medium management method, this area management table 41
For example, 05 recorded at position 4 in the area management table 41 is a combination of the contents of physical block 4 and the physical block 5. Indicates that the block contents are continuous, and FF indicates that there are no subsequent blocks (the file ends with this block). Another general-purpose O8 management method is to There is also a management method (not shown) in which block numbers are listed and recorded for each file as part of management information such as a file name.

In such a magnetic medium type management system, file contents are normally recorded sequentially starting from empty blocks at low addresses, so the file contents are stored in a plurality of discontinuous blocks.

In large-capacity optical discs, not only does the size of such an area management table become large, but it is also necessary to search this table. Because of this, the seek time is slow and
This is not practical as a management method for optical discs that are likely to store many large-sized files.9 Since the present invention can manage files in units of large contiguous areas, it is possible to realize a simple management method that avoids these problems. .

FIGS. 5 to 11 schematically show the arrangement within the optical disc in this embodiment. 51 in FIG. 5 is a file entry for file A, and the file contents are from address OO to
Similarly, 52 and 53 are file entries for files B and C, respectively.

61 is an unused area list, and addresses 450 to 10
000 indicates an unused area.

Fig. 6a shows a diagram when files A and C are updated, and in this embodiment, the entire file is newly added to an unused area (in Fig. 6a, the file A and C are updated.
A', illustrated as F I LEC').

At this time, due to the recording area of the file, file entry 5
Change 1.52. Also, the area where files A and C were recorded before the update (in Figure 6, addresses OO to
100.180 to 450) can be released and reused, so they are recorded as the unused area list 62.63.

Figure 7 shows the state of the optical disc in Figure 6a, and Figures 8 to 9.
The figure shows an example in which a new file D is recorded on the optical disk in the state shown in FIG. 6. Here, the size of the file D is assumed to be 120.

In this embodiment, as shown in FIG. 7, files are preferentially added to the unused area with the largest size. In particular, when using an optical disc that cannot be overridden, the end of the file is often where the file is recorded for the first time, so there is no need to wait for the file to rotate for deletion (unless the file before the update remains). The same effect can be achieved by deleting unused space when files are updated or when garbage collection is performed.)

In FIG. 7, by recording file D, a file entry 54 is recorded and the unused area list 63 is updated (hatched area in the figure). Indicates a case where an unused area for recording a file cannot be obtained. In this case, check the unused area list and record preferentially in an unused area larger than the file size (in Figure 8, record at addresses 180 to 300). At this time, if the unused area after the file is written (addresses 300 to 450 in Figure 8) becomes smaller than a certain size, it is prioritized over a larger area to avoid fragmentation. There is also a way to write.

FIG. 9 shows an example in which file D is divided into two unused areas and recorded. This recording method is used when there is no unused area larger than the file size.

In this case, the file entry 54 records two area designation sections such as 54a and 54b.

Next, Figures 10 to 11 show examples of integrated management of unused areas from the state shown in Figure 6a. In Figure 10, the area of file B (addresses 100 to 180) is released. In FIG. 10, which shows an example of this case, since there are unused areas before and after, these are integrated and managed as one unused area. In addition, if there is an unused area only in the front, or if there is an unused area only in the back, the same thing can be done. In addition, even if this integrated management is performed, if there is still a small unused area on the optical disc, or if it is specially specified, the unused area will be consolidated by garbage collection.Normally, unused areas are Although it is integrated into one area,
Since this process requires extensive rewriting within the optical disc, a method of integrating only some unused areas as shown in FIG. 11 may also be considered.

In addition, in FIG. 9 of this embodiment, a method was explained in which unused areas are filled in sequentially from the beginning when writing to continuous areas into which a file is divided. In order to avoid file fragmentation, it is also possible to leave the area as an unused area without writing the file, and integrate it with other unused areas at the time of garbage collection. In addition, when using an optical disc that cannot be overridden, it is possible to erase information in the area in advance when the area is released and becomes an unused area or at the time of garbage collection. There is no need to wait for rotation for erasing, and writing can be performed at high speed.

Effects of the Invention As a result of the effects of the present invention, it becomes possible to store files in a continuous area within an optical disk, and simple area management can be achieved, improving the reliability, slow seek time, and rewriting of rewritable optical disks. Accordingly, it is possible to provide an efficient management system for rewritable optical discs that can avoid problems such as waiting for rotation.

[Brief explanation of the drawing]

Fig. 1 is a basic configuration diagram of this embodiment, Fig. 2 is an explanatory diagram of file entries, Fig. 3 is an explanatory diagram of an example of an unused area list, and Fig. 4 is an explanatory diagram of the magnetic medium management method in general-purpose O8. , FIGS. 5 to 11 are explanatory diagrams of area management within the optical disc in this embodiment. DESCRIPTION OF SYMBOLS 1... Optical disc, 2... Management information, 3... File entry, 4... Unused area list, 5... File area, 6... Optical disc control unit, 7... File system , 8... area management section, 9... file management section. Name of agent: Patent attorney Toshio Nakao (1 person) Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 a Figure 7 Figure 9 Figure 10 Figure 6 b'1118

Claims (6)

[Claims] (1) An optical disc that stores data and management information for the data on the same medium, an optical disc control unit that performs recording, playback, and erasure on the optical disc in units of sectors, and manages data in units of files using the management information. a file system, the management information includes a file entry for identifying an area in which a file is stored in an optical disk, and an unused area list indicating a storable area, and the area designation information in the file entry is , a rewritable optical disc management system characterized in that one or more continuous areas are described by the start of the area and the length or end position of the area. (2) The area specification information in the unused area list is described with respect to one or more unused areas by the beginning of the area and the length or end position of the area. The rewritable optical disc management system according to item 1. (3) The file system has an area management unit that selects a write area for a file using an unused area list, and the area management unit preferentially selects an unused area larger than the file size stored by the area management unit. A rewritable optical disc management system according to claim 1 or 2. (4) The file system has an area management unit that selects a write area for a file using an unused area list, and the area management unit selects an unused area where no file has been written or an unused area that has already been erased. 3. The rewritable optical disc management system according to claim 1 or 2, wherein the rewritable optical disc management system selects preferentially from a region. (5) The file system performs garbage collection processing to consolidate unused areas in the optical disk at a certain point using an unused area list, and erases the unused areas during the garbage collection. A rewritable optical disc management system according to claim 1, 2, or 3, characterized in that: (6) The rewritable optical disc management system according to claim 1 or 2, wherein the file system loads and processes file entries or unused area management lists into memory.