JPH0322046A - Control method for file using draw type storage medium - Google Patents

Abstract

PURPOSE:To easily use update and control a file by directly accessing the file from the OS (operating system) side through an address conversion table on a memory where the latest information is always written. CONSTITUTION:When a new file is registered or the file is updated, a pertinent directory is newly generated and is additionally written in another position of a medium. Since the actual address of the directory is changed at this time, contents of the address conversion table on the memory are rewritten with the latest information, and new address correspondence relations are additionally written in an address conversion history table on the medium. The OS accesses the file through the address conversion table on the memory to see the file always controlled in the latest state. Thus, the file is easily accessed and controlled in the general OS level, and the erased file is easily restored.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for managing files organized in a write-once storage medium typified by an optical disk.

Conventional technology Unlike magnetic disks, data cannot be rewritten on write-once optical disks, so if this is used as a file medium, special processing is required to update (add, delete, change) files.

In conventional file systems using write-once optical discs, the management of files and data is left to the search system, and general-purpose operating systems (for example, MS-DO
It does not have an interface at the MS-CDex) level, and handles file additions and changes by adding new search information, and deletes files (logical deletion). The method used was to make file search information virtually invisible.

Problems to be Solved by the Invention In the conventional file management method described above, there is no application interface at the general-purpose OS (operating system) level, so it is not possible to directly access files (including file updates) from the higher-level system. The basic problem is that it cannot be done. 1. Files that have been deleted actually remain on the optical disk, but even if you want to restore and use the deleted file, you may have forgotten the identification number of the deleted file. If so, I couldn't search for it.

This invention was made in view of the above-mentioned problems, and its purpose is to make it easier to access and manage files from the general-purpose OS level, and to easily restore deleted files. The purpose is to provide a file management method.

Means for Solving the Problems Therefore, in the present invention, when organizing files in a write-once storage medium, the latest correspondence between the real address of each file's directory on the medium and the virtual address seen from the operating system (OS) is determined. Information is created as an address conversion table in a readable/writable memory, and all information related to the above relationship is created as an address conversion history table on the medium.

Operation When a new file is registered or a file is updated, a new corresponding directory is created and written to the new location on the medium. At this time, since the real address of the directory changes, the content of the address translation table in the memory is rewritten to the latest one, and the newly generated address correspondence relationship is added to the address translation history table on the medium. By accessing files via the address conversion table in the memory, the OS always sees files that are managed in the latest state. Furthermore, since the address translation history table retains the above-mentioned past correspondence, deleted files can be restored as necessary by searching this table.

Embodiment FIG. 5 shows an outline of a file system in which the present invention is implemented. In this system, CPUl1 main memory 2
, a file processor 4 consisting of an interface 3, etc.
A disk player 5 for reading and writing data on a write-once optical disk as a file medium, and an input/output control device 9 for controlling a keyboard 6, a display 7, a printer 8, etc. are coupled to the disk player 5.

In the example explained below, file A is stored on the write-once optical disc.
Assume that file B has already been registered. FIG. 1 shows the initial state of the file.

File A consists of three members al, a2, a3,
The directory of file A is the entry for each member a1, a2, a3 (a 1) (a 2) (a
3). Each member al, a2 of file A
, a3 are written in a predetermined area of the optical disk, and the file A directory (al) (a2) (
a3) is written to the real address (k+1) of the directory area of the same optical disk.

Similarly, file B consists of two members b1 and b2,
The actual data is written in a predetermined area of the optical disc, and the directory of file B (bl
) (b2) is the real address (k+2
) is written in.

Then, the virtual address (m) is assigned to the directory of file A seen from the OS level, and the directory of file B is also assigned a virtual address (m).
A virtual address (m+1) is assigned to the directory. In this case, the correspondence relationship (m) between virtual addresses and real addresses is stored on the main memory 2 of the file processor 4 →
An address conversion table showing (k+1) and (m+1)→(k+2) is created. An address conversion history table (with the same contents as the address conversion table in the initial state) shown in FIG. 1 is also created on the trenched optical disk.

When adding a new member a4 to file A from the above-mentioned initial state, each piece of management information is processed as shown in FIG. 1
New directory (al) of file A with entry (a4) for added member a4 (a2)
(a3) (a4) is the real address of the optical disk (
k+3), and then the correspondence between the virtual address (m) and the real address (k+3) is added to the address conversion history table on the optical disk. Furthermore, press the button on the address conversion table in memory, and change the old correspondence (m) → (k
+1) is rewritten as a new correspondence (m)→(k+3).

By processing as above, file A is saved at the OS level.
When accessing, (m) → (k+3) is extracted from the address conversion table on the memory, and the latest directory of file A (al) (a2) (a 3) is extracted from the optical disk according to the real address (k+3).
(a4) and select any members a1, a2, a3
, a4 can be accessed.

Next, when member a2 of file A is deleted, processing is performed as shown in FIG. 1. Entry items for deleted member a2 (
Directory of new file A excluding a2) (a
l) Create (a3) (a4), write it to the real address (k+4) on the optical disk, and add the new correspondence (m)→(k+4) to the address conversion history table on the optical disk.

Furthermore, (m
) −+ Rewrite the term (k+3) as (m) → (k+4).

By processing as above, when file A is accessed from the OS side via the address conversion table, the directory (a l) (a 3
) (a 4) will be extracted. Therefore, file A from which member a2 has been deleted will be accessed. However, the actual data of deleted member a2 remains on the optical disk, so if you want to restore it, search the address conversion history table on the optical disk sequentially from the end to the beginning, and then search the virtual address of file A ( m)
The second term (m) → (k+3) written in is extracted, and the directory (al) (a
2) It is possible to extract (a 3) (a 4) and extract (revival) the deleted member a2 according to the entry (a2) therein.

Next, when the contents of member b2 of file B are changed, processing is performed as shown in FIG. 1. New direct 'J (bl) with updated entries for changed member b2
(b2) and assign it to the real address on the optical disk (
k+5) and the new correspondence (m+1) →
(k+5) is added to the address conversion history table on the optical disc. Furthermore, address translation table K in memory
Then, the term (m+1) → (k+2) is changed to (m+1) →
Rewrite it to (k+5).

By processing as described above, when file B is accessed from the OS side via the address conversion table, a new file B including a new member b2 is accessed according to the new directory of the real address (k+5).

Effects of the Invention As explained in detail above, according to the file management method according to the present invention, files are directly accessed from the OS side via the address translation table in memory, which always contains the latest information. You can use the file,
Updates and management become simpler and easier. Furthermore, since the above-mentioned address conversion history table is created in the write-once type medium, by searching it, it is possible to see the file before the update, and it is also possible to easily restore the deleted file.

[Brief explanation of drawings]

1 to 4 are conceptual diagrams showing the transition of file management information according to the method of the present invention, and FIG. 5 is a schematic diagram of a system implementing the method of the present invention.

Claims (1)

[Claims] When organizing files on a write-once storage medium, the latest information on the correspondence between the real address of each file's directory on the medium and the virtual address seen from the operating system is created as an address conversion table in a readable/writable memory. A file management method using a write-once storage medium, characterized in that all the information regarding the correspondence relationship is created as an address conversion history table on the medium.