JPH02132516A - System and method for write enable type optical disk controlling - Google Patents

Abstract

PURPOSE:To realize an updating operation with the reduced overhead by adding an updating means into an operating system to record again entirely a directory file and also to additionally record the history information on a directory file table set in a memory. CONSTITUTION:An operating system 1 includes a directory file table reproduction means 2, a memory 3, and a directory file table updating means 4. The means 2 reproduces a direct file table into the memory 3 based on the history information. At the same time, the means 4 records the updating operation of a directory file table with a small quantity of history information. Thus it is possible to obtain a hierarchical directory control system which can use effectively the recording area of a write enable type optical disk with the reduced overhead of the updating operation.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a management method for an optical disk as an external storage device for a computer.In particular, it provides high-speed file access suitable for storing code data.Efficient updating with low overhead is possible. The present invention relates to a writable optical disc management system and method.

2. Description of the Related Art Optical disks, which have a capacity several tens to hundreds of times larger than conventional magnetic storage media, are beginning to be used as external storage media for computers. Regarding read-only optical discs, in order to share data, data on the media can be shared between various information processing systems and operating systems [e.g.
S-DOS (a trademark of Microsoft Corporation) and UNIX (
Studies were conducted on standard formats and management methods to enable use with general-purpose operating systems such as the OS developed by ATT. ISO98E was discussed and ISO98E
Standardization was carried out as 30 [Reference: I●S●
O9 8f3 0, April 1988 r Volume φ and ● File ● Structure ● Of ● Sea●
D●Romufo●Information Day●Interchange” (ls0911iBO.Apr.l988
rVolume and File Struct
r of CD-ROM for Information
lon InterchangeJ) Co.

However, current writable optical discs use a system-specific file management method, and the information, operation commands, etc. recorded on the optical discs are not compatible. For this reason, proposals for a standard format have begun to be made for write-once optical discs as well.

One of these is a method proposed by DEC Corporation based on 1809880 [hereinafter referred to as DECtl! Draft system, abbreviations, and references: "Working φ Paper●For●Volume●and●FileFistStructchairFistof●Warm●ForContestI.Fomesi2in●Interchange" 7 August 1 9 8 8 (r
Worklng Paper tar Volume
nd File Structure of WORM
for Informat1onInterchan
ge J. 7 August 1988)]. D.E.
In the CtJA proposal system, like the above-mentioned ISO9860, hierarchical directories are managed using a directory file (hereinafter abbreviated as DF) and a bus table (hereinafter abbreviated as PT). The DF is a file that records information about files and subdirectories within a directory, and the PT is a directory file table that collectively records the positions of DFs and their hierarchical relationships. I SO9E380 and DE
In the method proposed by C, the search speed of the DF is increased by loading the PT of and into the memory and performing the search.

Problems to be Solved by the Invention In the DECffl proposed system, when updating a file or subdirectory within a directory, the entire DF in which the information is recorded is newly recorded on an optical disc to update the DF. Since the DF address changes due to the update, the entire PT having the DF address information is further recorded on the optical disc.

Since a PT is usually several kilobytes or more in size, if the entire PT is re-recorded every time a file is updated, the update overhead will be large and the efficiency of using the WORM recording area will deteriorate. This problem is particularly serious when recording a large number of small-sized code information files or when using online processing that involves frequent updates.

In view of the above problems, the present invention provides a writable optical disc management system and method that can update DF with less overhead by recording PT updates in the form of history information indicating the change method. The purpose is to

Means for Solving the Problems In order to solve the above problems, the present invention provides a writable optical disc in which data files, directory files, and a directory file table for collectively managing the directory files are recorded on the same medium; It has an operating system that has a mechanism for managing the location of directory files using this directory file table, a storage device that stores the directory file table, and an optical disk control device that performs recording and playback on this writable optical disk, A directory file table update means for re-recording the entire directory file in the operating system and additionally recording history information of the directory file table in the storage device, and a reproduction means for reproducing the directory file table in the internal management device from the history information. It is configured to have

According to the above configuration, the reproduction means reproduces the directory file table in the storage device from the history information, and the update means records the update of the directory file table using history information with a small amount of information, thereby making it possible to write. It is possible to realize a hierarchical directory management system that can efficiently use the recording area of an optical disc and has little update overhead.

Embodiment FIG. 1 shows a basic diagram of the present invention. Figure 2 shows a conventional example, DECtJ! ! Explanatory diagrams of the proposed system, Figures 3 and 4 are D
This is an example of the management information of the hierarchical directory used in the EC proposed method and the present method, and the updated version thereof.

Further, FIG. 5 is an explanatory diagram of updating a directory file table using history information used in this method, and FIG. 6 is a diagram showing another data arrangement within a writable optical disc.

Although the present invention can be applied to a rewritable optical disc as a writable optical disc, this embodiment will be explained using a write-once optical disc (hereinafter abbreviated as WORM).

In FIG. 1, 1 is an operating system (hereinafter abbreviated as OS), 2 is a directory file table reproducing means in OSI (hereinafter abbreviated as DFT reproducing means), 3 is a storage device, and 4 is a directory file table updating means (hereinafter abbreviated as DFT reproducing means). , abbreviated as DFT updating means), 5 is an optical disk control device,
6 is an example of WORM and its file arrangement.

FIG. 2 shows a block diagram of the DEC proposed method for comparison.

In FIG. 2, 11 is the OS, 21 is a directory file table loading means (hereinafter abbreviated as DFT loading means), 3
is a storage device, 41 is a directory} IJ file table update means (hereinafter abbreviated as DFT update means), 5 is an optical disk control device, and 6 is a WORM and an example of its file arrangement.

The thin solid lines in Figures 1 and 2 indicate WORME! The flow of data processing during exchange, the thick solid line indicates the instruction and flow of data processing during update, and the broken line indicates pointer information within each record. Although a magnetic medium such as a hard disk can also be used as the storage device 3, an internal memory is usually used.

FIGS. 3 and 4 show each record format used in the DEC proposed method and an example of its update. This embodiment also uses this record format as is. Third
Figure (a) is an example of a hierarchical directory structure. Third
The double frame in figure (a) indicates each directory file (hereinafter referred to as D
(abbreviated as F), single frames indicate data files.

FIGS. 3(b) and 3(c) are examples of the directory file table (hereinafter abbreviated as DFT) and DF of directory BBB in the case of the directory structure shown in FIG. 3(a). In FIG. 3(b), 90 is an example of DFT, 81 is the directory identifier length (byte length), 82 is the DF address, 83 is the parent directory number, and 84 is the directory identifier. The arrow line from FIG. 3(b) to FIG. 3(a) indicates pointer information to the DF. A directory number (subscript number on the upper left in the figure) is randomly assigned to each directory from the upper hierarchy, and the parent directory number 83 is recorded using this directory number. DF7 in Figure 3 (C)
0 is an example of DF' of directory BBB, which is composed of file location size ● identifier recording identifier} IJ, and 701 to 705 are self (BBB), file 3, and directory D, respectively.
, E, and F. Figure 4(a)~
(C) shows an example after the directory DD is created under the directories BBB in FIGS. 3(a) to (C), respectively.

First, for convenience of explanation, the updating method of the DEC proposed method will be explained using FIGS. 2 to 4.

In the DEC proposed method, the latest DFT (corresponding to the n-th DFT in FIG. 2) is loaded into the storage device 3 by the DFT loading means 21 when the WORM 8 is replaced. Here, OS1
When an instruction to create a directory DD under the directory BBB is issued to the OS 11, the OS 11 performs update processing as follows.

First, record the DF of the directory DD to be created in the WORM8, and record it in the DF70 of the BBB in FIG. 3(c) as shown in FIG.
Entry of directory DD as in DF7 1 of C) I
J 7 0 6 is added and updated, and this is re-recorded in WORMθ. In addition to these processes, the DFT updating means 41 updates the DFT loaded into the storage device 3 as shown in FIG.
) DFT95 of FIG. 4(b)
Rewrite it in the form of And the whole new DFT95 is WO
Re-record on RM8 [equivalent to the (n+1)th DFT in FIG. 2, and record the (n+1)th position information as well.

Since rewriting of recorded information does not work with WORM6,
In this way, an update method by re-recording is adopted. Note that the position information is terminal information for indicating the position of the latest DFT and volume information at that time.

Although the size of the DFT depends on the number of directories, it is usually assumed to be several kilobytes or more.

Therefore, in the method proposed by DEC, the entire path table is recorded each time a file is updated, resulting in a large overhead, which deteriorates the usage efficiency of WORM8. In particular, when recording many small files such as code information, a large number of directories are created and the DFT tends to become large, and efficiency becomes even worse when used in online processing where frequent updates occur. .

Therefore, in the present invention, a method is adopted in which the DFT is updated by recording it in the form of history information indicating the changes, without re-recording the entire DFT. An example of updating this DFT is shown in the fifth section.
As shown in the figure. Figure 590 shows the DFT before update (Figure 3(b)
)9 is the same as 0), 95 is the updated DFT (Fig. 4 (
b) 9 Same as 5), 99 is an example of history information in this case.

Create a directory DD and convert DFT90 to DFT9
To rewrite to 5, insert the DD DFT record,
It is necessary to change the DF address of BBB to the re-recorded address (the changed part is indicated by a halftone dot). To insert the DFT record of DD, insert the second half 92 from the insertion position D
FT record ■ Move to the forwarding destination ■ by the size, and perform DFT
Just insert record ■. At this time, since the directory number is shifted by 1 due to the creation of the DD, it is necessary to increment the parent directory number after the DD by 1. Furthermore, the DF position of BBB can be changed by recording the DF address change position (■) and the new address. As described above, since the DFT can be updated through relatively simple processing, only the parameters necessary for updating, such as the history information 99, may be recorded in the WORM 6 as history information. Using this history information, it is possible to reproduce the DFT by simulating the update process after a certain point in time, without having to re-record the entire updated DFT.

A comparison of the process shown in FIG. 1 with the DEC proposed method shown in FIG. 2 will be summarized below. In the DFT reproducing means 2, D in FIG.
As an alternative to the FT reading means 21, the history information recorded in the WORM 6 is sequentially read out, its contents are interpreted, and the latest DFT is reproduced in the storage device 3. Furthermore, in the DFT updating means 4 of FIG. 1, the DFT updating means 41 of FIG.
As an alternative means, an update process is performed in which only the history information is recorded without re-recording the entire DFT.

As described above, in the present invention, when updating the DFT, it is only necessary to record history information of at most several tens of bytes, and the WOR
The efficiency of using M6 can be greatly improved.

Although Fig. 1 shows a method of recording history information in reverse address order starting from the end of the recording area of WORM6, it is also possible to define a certain recording area for history information and DF using volume information (as disclosed in the patent). Structure of claim 3). With this method, it is possible to adopt an arrangement that reduces the distance between the DF and the data file, and it is possible to suppress seek time and speed up access to the file.

In addition, when the number of historical information increases, it takes time to reproduce the DFT, so when a certain number of historical information has been accumulated or when a special instruction is given, the DF in the storage device 3 is
There is also a way to save (re-record) T periodically.

An example of data arrangement within WORMe in this case is shown in FIG. The broken line in FIG. 6 is pointer information indicating the beginning position of the history information after saving. In this case, since it is only necessary to reproduce the history information after the save process, the reproduction process time can be shortened.

Effects of the Invention The effects of the present invention provide a hierarchical directory management method for writable optical discs that enables high-speed file access and efficient updating with little overhead.
It can be used as an external storage device for computers, which was previously difficult to do, especially as a storage device suitable for storing code data.
It can contribute to expanding the application fields of optical discs.

[Brief explanation of the drawing]

FIG. 1 is a basic configuration diagram of the present invention, and FIG. 2 is a conventional example D.
ECt! A block diagram of the proposed method, Figures 3 and 4 are hierarchical directories used in the present invention and the DEC proposed method} A diagram showing an example of management information of the IJ structure, and Figure 5 is an update of the directory file table used in the present invention FIG. θ, a diagram showing the method and history information, is a diagram showing another example of data arrangement of WoRM. DESCRIPTION OF SYMBOLS 1... Operating system, 2... DFT reproducing means, 3... Storage device, 4...
Directory file table updating means, 5... optical disc control device, 6... write-once optical disc. Name of agent Patent attorney Shigetaka Kurino and 1 other person No.1 Zuzuka No.1

Claims (1)

[Claims] 1) An optical disc that records a data file, a directory file, and a directory file table that collectively manages the directory files on the same medium, and uses the directory file table to manage the location of the directory file. an operating system having an operating system, a storage device that stores the directory file table, and an optical disk control device that performs recording and playback on the optical disk; A writable optical disc management system comprising: a directory file table update unit for additionally recording history information in a file table; and a playback unit for playing back the directory file table in the storage device from the history information. 2) The writable optical disc according to claim 1, wherein processing is performed to save the directory file table in the storage device as it is at the time when a certain number of history information is created or at a specially designated time. management system. 3) Claim 1 or 2, wherein a certain address range is set as an area used by the operating system to record a data file, a directory file, a directory file table, or historical information.
The described writable optical disc management system. 4) An optical disc that records data files, directory files, and a directory file table for collectively managing the directory files on the same medium is used as an external memory, and includes an optical disc control device that records and plays back on the writable optical disc. , in a computer system having an operating system having a mechanism for managing the location of directory files using the directory file table and an internal memory storing the directory file table, re-recording and storing directory files in the operating system; A writable type device comprising the steps of: updating a directory file table to additionally record history information of a directory file table in the device; and reproducing the directory file table in the storage device from the history information. Optical disc management method.