JPH03183090A - File control system for draw type optical disk - Google Patents

Abstract

PURPOSE:To access a file regardless of a medium by converting a file identification number to a physical block number by a correspondence table when accessing the file. CONSTITUTION:In an input / output control part 3, a DRAW type optical disk control part 31 is provided to control a DRAW type optical disk 4 and a hardware disk control part 32 is provided to control a hardware disk 5. When the DRAW type optical disk 4 is used, an instruction is outputted from a main control part 1 to the input / output control part 3 by applying the use start instruction of the DRAW type optical disk 4 to the main control part 1 and a main memory 2 reads in a correspondence table 41 to make correspondent the file identification number and the physical block on the DRAW type optical disk 4. The correspondence table 41 can be put in the main memory 2 as it is. However, the correspondence table 41 is temporarily stored onto the hardware disk 5 and read into the main memory 2 as needed. According to an operating system to be used, the file on the DRAW type optical disk 4 is used and in such a case, the instruction is applied to the main control part 1.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a file management method for accessing files using file identification numbers in an information processing apparatus having an external storage device, and in particular, the present invention relates to a file management method for accessing files using a file identification number in an information processing device having an external storage device. Regarding management methods.

(Prior Art) Generally, data on an external storage device is managed in units called files. File management methods vary depending on the operating system, but the typical one is UNIX-?
This is a tree-structured file system found in MS-DO8, etc. In this case, each file is identified within the medium by a unique file identification number. Access to the file is
This is done by calculating the physical block number in which the file entity or file information is stored from data that is a combination of the medium identification name and the file identification number.

A more specific explanation will be given using the UNIX operating system as an example. UNIX files are in the medium (
(or within a logical medium) by an arbitrarily assigned file identification number called an l-node number.

Each medium is used by being divided into four areas as shown in FIG.

We will briefly explain each area. The budpultsk 81 contains data for configuring a UNIX system, and the superblock 82 contains information such as the size of the medium and the size of free space.
Store data regarding the entire medium. l list 83
is a part in which one node of each file is stored in order of I-node number.

An l node is an information section of a file that corresponds one to one with a file, and manages attributes such as size and access rights as well as a physical clock number that stores the entity. The data area 84 is a part that stores actual data.

As mentioned above, the sizes of the four areas are determined by the system initial settings, so the block number of one node is (boot block size) + (super block size) + (1 node size * number of east nodes) ), and files can be accessed from l-node data.

Furthermore, since a tree-structured file has a special file called a directory for associating the file name with the l-node number, the user can access the entire entity using only the file name. The series of processes of obtaining the reference node number from the file name and accessing the entity from the i-node queue number via the l-node are UNIX
The system will do this.

Since write-once optical discs cannot be rewritten, each time the file data is modified, the file entity or the block number storing the file information is changed, making it impossible to associate the file identification number with the physical block number. For this reason, it is not possible to directly extend the conventional file management method to write-once optical discs (A).

Therefore, when using a write-once optical disc in a system that manages files using 7-aisle identification numbers, data on the write-once optical disc is handled differently from data on rewritable media such as hard disks. .

In many cases, there is no concept of a file for data on a write-once optical disc, and access to data is simply an Ilo.
It is carried out as therefore.

The user (or program) must execute processing while being aware of which medium the requested data is on, and in the case of data on a write-once optical disk, it is necessary to know in which block physically the data is located. Processing must be carried out with this in mind.

Also, a method is known in which search information indicating which block each piece of data is located in is always managed on a hard disk, but in this case, it cannot be used in any system other than a system that is attached with a hard disk that stores the search information.

(Problem to be Solved by the Invention) In the file management method on the write-once optical disk according to the conventional technology described above, the user needs to be aware of which medium the requested data is on when executing the process. The drawback is that processing must be performed while being aware of which block the data on the optical disk is located.

On the other hand, in a method that constantly manages search information on the hard disk, such as which block each data is placed in,
It has the disadvantage that it cannot be used except in systems that come with a hard disk to store search information.

An object of the present invention is to provide a write-once optical disc with a correspondence table between file identification numbers and physical block numbers, and to read the correspondence table into the main memory or hard disk when the write-once optical disc starts to be used. When accessing a file, the file is accessed via the correspondence table, and when the use of the write-once optical disc is finished, the changed correspondence table is written onto the write-once optical disc. This eliminates the above disadvantages. To provide a file management system on a write-once optical disk configured so that files on the hard disk can be viewed as equivalent to files on a hard disk.

(Means for Solving the Problems) A file management method on a write-once optical disk according to the present invention stores data in an external storage device constituted by a write-once optical disk on a file-by-file basis, and identifies the medium in which the file is stored. The file is identified by the combination of name and unique file identification number within the medium.

In the above structure, the present invention is provided with a correspondence table between file identification numbers and physical block numbers on the write-once optical disc, and comprises a reading means, an access means, and a writing means. It is configured so that files on the computer can be viewed as equivalent to files on the hard disk.

The reading means is for reading the correspondence table into the main memory or the hard disk when starting to use the write-once optical disc.

The access means is for accessing files on the write-once optical disc via the correspondence table.

The writing means is for writing the changed correspondence table onto the write-once optical disc at the end of use of the write-once optical disc.

(Example) Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a file management method on a write-once optical disc according to the present invention.

In Figure 1, 1 (main control section), 2 main memory,
3 is an input/output control unit; 31 is a write-once optical disc control unit; 3
2 is a hard disk control unit; 4 is a write-once optical disk; 4
1 is a correspondence table, 6 is a hard disk, and 6 is an arithmetic processing unit.

In FIG. 1, the parts that manage files include a main control unit 1 for controlling the entire system, a main memory 2, an input/output control unit 3 for controlling input/output, and an external storage device. It is composed of a shaped optical disk 4, a hard disk 5, and an arithmetic processing section 6 for performing calculations.

The input/output control section 3 includes a write once optical disk control section 31 for controlling the write once optical disk 4, and a hard disk 5.
It is equipped with a hard disk control section 32 and e for controlling. The write-once optical disc 4 also has a correspondence table 41 that associates file identification numbers with physical blocks.
is stored.

When using the write-once optical disc 4, by giving a command to the main control unit 1 to start using the write-once optical disc 4, the input/output i!
A command is issued to the IllI controller 3, and the correspondence table 41 on the write-once optical disc 4 is read into the main memory 2. The correspondence table 41 can be placed in the main memory 2 as is, but in this embodiment, the correspondence table 41 is temporarily stored on the hard disk B and read into the main memory 2 when necessary. ing. Depending on the operating system used, registration processing may be necessary in order to use the files on the write-once optical disc 4, in which case commands are given to the main control unit 1 as necessary.

When a file on the write-once optical disc 4 is used after the start-of-use process is performed, the file identification number is converted into a physical block number using the correspondence table 41 and then accessed. When writing to the write once optical disc 4, the data in the correspondence table 41 is also changed at the same time.

Here, this rewriting is performed for the first time when the correspondence table 41 is written on the main memory 2 or the hard disk drive write-once optical disk 4 when a use end command is given, and if there is no change, writing is not performed. do not have. At the same time as writing, the correspondence table 41 on the main memory 2 and the hard disk S is erased. The changed correspondence table 41 is written at a predetermined position, for example, at the last position of the usable area of the write-once optical disc 4, and with a predetermined size. Therefore, this write once optical disc 4 will be used next. For diagnosis, 1. - Read the correspondence table 41 again from that location.

File management on the write-once optical disk 4 is possible using any file system that identifies files using file identification numbers using the method described above. For example, when processing files on optical disk 4,
Give a concrete explanation.

FIG. 2 is an explanatory diagram showing an example of the format of the correspondence table 41. The volume name 71 is a volume identification name uniquely assigned to each write-once optical disk, the node number 72 is the l-node number assigned to the next file to be created, and the free block number 73 is an unused disk on the write-once optical disk 4. The first number of each block is managed, and the number of the block in which the l node of the file with the nth block number 71n6tl node number n is stored is managed.

For example, the second block number 14-2 indicates a block in which five nodes with an l-node number of 2 files are stored, and the block in which the file is stored can be determined from the l-node data.

In order to use the files on the write-once optical disk 4 in a UNIX file system, it is necessary to read the correspondence table 41 and perform a link (mounting process) to the file system at the beginning of use. If the above processing is performed at the beginning of use, it is necessary to refer to the correspondence table 41 at the time of access, but other than the above, files on the write-once optical disc 4 can be handled in the same way as files on a hard disk. Moreover, if the write-once optical disc control unit 31 performs all the processing for referring to the data in the correspondence table 41, the user (or program) does not need to be aware that the file is on the write-once optical disc 4.

Below, processing such as open processing, creation, read/write processing, and closing of files on the write-once optical disc 4 using the correspondence table 41 will be explained.

First, open processing will be explained. Main control part 1
requests the write-once optical disk control unit 31 to open a file using the l-node number as a parameter, the write-once optical disk control unit 31 determines in which block the node corresponding to the given l-node number is stored. The correspondence table 41 is checked and one node is read into the main memory 2. Load! The relationship between the created lnode and the process is done in the same way as for files on a hard disk. Furthermore, the user (or program) performs file open processing using the file name as a parameter, but the process of deriving the medium and l-node number from the file name is also performed in the same way as a UNIX system uses a hard disk. All software-dependent processing is absorbed by the input/output controller 3.

Next, the creation process will be explained.

The newly created file has the free number 7.
Given the l-node number managed by 2, free-1
The value of node number 72 is incremented by one. One node corresponding to this l-node number is taken from the block indicated by free block number f3, and the value of free block number 73 is incremented by the number of blocks used in the l-node. The process of registering in the file system, that is, the process of writing the file name and l-node number in the directory, is executed in the same way as the process of creating a file on the hard disk.

Next, read/write processing will be explained.

The reading process is the same as for a hard disk. In other words, it is a process of checking which block on the write-once optical disk 4 contains the data to be read from the l-node data on the main memory 2, and then reading the data. In the write process, the area for writing data is secured by the required number of blocks from the block indicated by the block number 73, and the value of the free block number 73 is incremented by that amount. Along with this, the data of the l node is also rewritten.

Finally, close processing will be explained.

The closing process is the same as in the case of a hard disk, and one node that stores the latest information regarding the file, such as modification time and used block number, is written to the write-once optical disk 4.

(Effects of the Invention) As explained above, the present invention reads the correspondence table between the file identification number and the physical block number stored on the write-once optical disk at the beginning of use, and uses the above correspondence table when accessing the file. Converting a file identification number to a physical block number has the effect of absorbing the non-rewritable nature of write-once optical discs. If such hardware-dependent processing is executed in the input/output processing unit, files on the write-once optical disk and files on the hard disk will appear equivalent to the user or program, and files can be accessed without being aware of the medium. There is an effect. This method is effective when using an optical disk as an external storage device, which has characteristics that hard disks do not have, such as large capacity, interchangeability, and portability.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a file V management method on a write-once optical disc according to the present invention. FIG. 2 is an explanatory diagram showing an example of the format of the correspondence table shown in FIG. 1. Figure M3 is an explanatory diagram showing the format of the hard disk for the τ)NIX file system. 1... Main control unit 2... Main memory 3... Input/output control unit 4... Write-once optical disc 5... e-hard disk 6... Arithmetic processing unit 31... - Write-once optical disc control Part 32...Hard disk control 11 41...Correspondence table 71...Volume name 72...Node number 73.74-1, 74-2. F4-8.74-n・-・
-・Block number 81...Put block 82 ・ 83 @ 84 ・・Super block list...Data area

Claims (1)

[Claims] A write-once type in which data is stored in an external storage device using a write-once optical disk in file units, and the file is identified by a combination of the identification name of the medium in which the file is stored and a unique file identification number within the medium. In the file management method on an optical disk, a correspondence table between the file identification number and a physical block number is provided on the write-once optical disk, and the correspondence table is stored in the main memory or on the hard disk when the write-once optical disk starts to be used. a reading means for reading, an access means for accessing the file on the write-once optical disc via the correspondence table; and an access means for accessing the file on the write-once optical disc via the correspondence table; A file management system on a write-once optical disc, comprising a writing means for writing on the write-once optical disc, and configured to make files on the write-once optical disc appear equivalent to files on a hard disk.