JPH07105067A - File control system - Google Patents

Abstract

PURPOSE:To shorten the write time of a magnetic disk and to speed up the access of the same file by partially copying CD-ROM file data in a magnetic disk device. CONSTITUTION:When a use opens the CD-ROM file 101, the file having the same area is generated in the magnetic disk device 104. When a first read request is given, the data block of a read area is read from the CD-ROM file 101 and it is copied in the same data block position for the file of the magnetic disk. When the CD-ROM file 101 is closed, the file of the magnetic disk device 104 is closed. In the case of reading data from the next CD-ROM file 101, it is read from the file of the magnetic disk device 104. Thus, data is read without being conscious of which file is a read destination and second and succeeding reading can be speeded up.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a file control method, and more particularly to a file control method for simulating a read-only CD-ROM file into a readable / writable file.

[0002]

2. Description of the Related Art Nikkei Byte 1992 / May issue, pp19
8 # 228, Uniforum 1991 Conference Proceedings, Dallas, Texas (Uniforum 1991
Conference Proceedings, Da-llas Texas), pp107
Recently, as disclosed in # 114, CD-ROM
Optical discs such as are attracting attention as recording media for supplying a large amount of programs and data. However, CD-RO
The M has a drawback that the read speed is as slow as 150 k / sec, and thus is difficult to accept in a multi-user environment.

Therefore, as a control for a CD-ROM or the like, there is a system in which a magnetic disk device and a CD-ROM device are combined to improve the access speed of the CD-ROM device. In this system, the magnetic disk device is a CD-
Since it is treated as a cache of the ROM device, when the data is on the magnetic disk, it can be read out immediately.
However, when writing data to the magnetic disk unit, the CD-
It takes a lot of time because the method of writing all the file data of the ROM is adopted. In addition, writing to the disk is wasted for files that are not referenced.
It is generally known that the CD-ROM file is read-only and cannot be rewritten.

[0004]

In the above system, the CD-
Since all the directory / file information and file data are written from the ROM device to the magnetic disk device, it takes a very long time and there is a problem that the disk is wasted. Also, no consideration is given to writing.

An object of the present invention is to reduce the time required to write a file to a magnetic disk device, reduce the required disk capacity, and to access the same area again,
Since the data can be read from the magnetic disk, it is intended to speed up the reading process.

[0006]

In order to achieve the above object, the file control method according to the present invention comprises a plurality of CD-ROM devices for storing files, a means for reading data from each CD-ROM device, and the CD. -A buffer memory which is a storage area for temporarily storing the data read from the ROM device, a magnetic disk device for copying the read data, and a CD on the magnetic disk device-
Means for constructing a ROM file structure, said buffer
A CD on the magnetic disk unit for each data unit in the memory
-ROM file access means and a CD-ROM file on the magnetic disk device where the data is written is a CD
A management table that manages which position of the file corresponding to the ROM file and indicates whether the data is only on the CD-ROM or whether there is copy data on the magnetic disk device, and reading of the data from the management table Is a file of a magnetic disk device or a file of a CD-ROM device.
By partially copying the ROM file data, the write time to the magnetic disk is reduced and the access to the same file to a large capacity, low speed access device is accelerated.

Further, when data is written on the magnetic disk by means of managing the file position corresponding to the CD-ROM file and judging access to the CD-ROM and access to the magnetic disk, this data is recorded. By corresponding to the position on the CD-ROM file, pseudo rewriting is possible.

[0008]

In the present invention, when the user first opens the CD-ROM file, the CD-R is loaded on the magnetic disk device.
A file having the same area as the OM file is created.
Next, when the user makes a first read request, the data block in the area to be read is read from the CD-ROM file and is copied to the same data block position in the magnetic disk file. User is CD-RO
When the M file is closed, the file on the magnetic disk device is also closed. Next, when the user reads the CD-ROM file by the same operation, it reads from the file of the magnetic disk device. In this way, it is possible for the user not to be aware of whether the read destination is from the CD-ROM file or the file on the magnetic disk, and to speed up the second and subsequent reading.

When the user performs a writing operation on the CD-ROM file, the contents of the corresponding file on the magnetic disk are rewritten and the management information is also rewritten so that the data already exists on the magnetic disk. , It is possible to rewrite the CD-ROM file in a pseudo manner.

[0010]

1 is a block diagram of a CD-ROM file system according to the present invention.

Reference numeral 101 is a CD-ROM file stored in the ISO9660 logical format, which is a CD-RO.
The M storage medium and its drive unit. 102 is a CD-
A controller that controls the operation of the ROM 101. 1
Reference numeral 04 is a magnetic disk device for storing virtual files and directories for storing the data read from the CD-ROM 101 and bitmap information indicating the block positions of the data and its drive device. 103 is a CPU for controlling the entire system, 105 is a program memory for storing a control program for operating the CPU 103, 10
6 is a buffer memory for temporarily storing the data read from the CD-ROM file 101, 107 is a memory for temporarily storing bitmap information, 1
08 is a memory for temporarily storing the path table,
A work memory 109 stores variables and tables used by the CPU 103.

FIG. 3 is a diagram schematically showing the structure of the storage area on the CD-ROM file 101. CD-RO
The data address in the M file 101 is represented by a logical block and is uniquely identified by a logical block number. The controller 102 uses this logical block number to specify the input address. The storage area is the volume attribute,
Volume descriptor 30 that stores the logical block position of the root directory and the logical block position of the path table
1, path table 3 that describes the hierarchical structure of the directory
02, and a directory descriptor 303 and a file descriptor 304. The path table 302 has a directory name length 305, extended attribute record length 306, directory position 307, and parent directory number 30.
8 and a directory name 309.

FIG. 4 shows the storage area of the virtual file 402. The virtual file 402 is a CD-RO
It has the same area as the M file 401, and the data blocks correspond one-to-one with the data blocks of the CD-ROM file 401. It also contains the CD-ROM file name and bitmap information. Bitmap 404 is
The size represented by 1 bit is 16 kbytes, and the bit position indicates the position of the data block in the virtual file 402. Hereinafter, one block is a 16-Kbyte data block. In the bitmap 404, a bit value of 1 indicates that the data block exists in the virtual file 402, and a bit value of 0 indicates that the data block does not exist in the virtual file 402. As a result, it is determined whether to read from the CD-ROM file or the virtual file.

FIG. 2 is a flow chart showing the reading operation of the CD-ROM file system according to the present invention. Figure 2
(A) shows an operation when the user reads a CD-ROM file. First the user is a CD-R
Open the OM file. Next, read the desired data block from the CD-ROM file, and finally read the CD.
-Close the ROM file. In contrast to the user operation of (a), (b) shows a processing flow of file control of the first read processing. In the initial state of (b), the magnetic disk device 104 has no directory hierarchy, virtual file, and bitmap information.

In 204 of FIG. 2B, the path table 302 is issued when the user makes a directory creation request.
To create a directory hierarchy of the CD-ROM in the magnetic disk device 104.

The directory creation process will be described with reference to FIG. In step 501, the path table 302 of FIG.
Is stored in the memory 108 by the controller 102.
The path table 302 is stored in ascending order from the root directory according to the level of hierarchy. Step 502
Then, the leading directory entry of the path table 302 stored in the memory 108 is extracted. In step 503, the directory name of the extracted directory entry is stored in the memory 109.

In step 504, the parent directory entry is extracted from the parent directory number of the same directory entry. In step 505, the directory name of the parent directory entry acquired in step 504 is inserted before the directory name stored in step 503. The above steps 504 to 505 are performed to step 506.
It is repeated until the parent directory number becomes 1, that is, the root directory.

By this processing, the full path name of the directory is stored in the memory 109. In step 507,
The directory represented by the full path name is the magnetic disk unit.
Create to 104. The processing of the above steps 502 to 506 is executed according to the judgment of step 508.
The entire directory hierarchy structure of the path table can be created by repeating up to the last record of.

After the user has completed the above operations, FIG.
The file is opened as in step 201 of (a).
In response to this operation, in the process 205 of FIG. 2B, the virtual file 402 shown in FIG. 4 is created in the magnetic disk device 104.

In the state of the virtual file 402 after the process 206 of FIG. 2B, the bitmap is all 0 and the data block size is 0. Next, the user performs the process 2 of FIG.
Do 02. On the other hand, in the first read of (b), the operation of FIG. 6 is executed.

In step 601, the C designated by the user
The virtual file corresponding to the D-ROM file is opened, and the bitmap information is stored in the memory 107.
In steps 602 and 603, the head data block position and the end data block position of the read designated by the user are calculated. Next, processing 6 for checking the state of the bitmap from the position of the first data block to the position of the end data block
04 to 607 will be described.

In the first step 604, the bit state of the read head block position, that is, 1 or 0 is stored in the memory. It is determined whether or not the bit of the next data block changes with respect to the value of this memory. When the value of the bit changes, the changed data block position is stored in the memory. Then, the bit state is stored in the memory.
This is repeated until the read end block. As a result of this processing, the status information table shown in FIG. 7 is created in the work memory.

The status information table includes a record 701 indicating the bit state of the read start block, and records 702 to 704 indicating the block position where the bit has changed.
It is composed of a record 705 indicating the end. If the record 701 is 1 and the end record 705 is stored next, it means that all the data blocks to be read exist in the virtual file. On the other hand, when the record 701 is 0, it means that the record does not exist in the virtual file. Further, in the case of missing teeth, if the number of missing teeth is too large, the effect of reading processing from a virtual file is lost. Therefore, a condition is set for the ratio of the number of missing teeth and the bit state 1, and if this condition is not satisfied, all are read from the CD-ROM file.
However, writing is not performed for the data block existing in the virtual file.

Since the bit map of the data block position from the start of reading to the end is all 0, 0 is entered in the record 701 of the status information table, and the next record
705 is coming. Therefore, steps 609 to 616 of FIG.
Then, the reading process is executed with reference to the status information table. In step 611, it is determined whether the data block to be read is in the virtual file or not based on the contents of the records 701 to 704 indicating the block positions where the bit change has occurred. If it is on the virtual file, the data block to be read is read from the virtual file into the buffer memory. If it is not on the virtual file, the data block to be read from the CD-ROM file is read into the buffer memory.

Referring to the status information table, the bit state of the read target block is 0. Therefore, steps 612 and 614 are executed. In step 612, the read target block is buffered from the CD-ROM.
Read into memory. In step 614, the data on the buffer memory is copied to an appropriate data block position in the created virtual file. Then, the bit at the data block position of the bitmap stored in the memory is set to 1. The above operation is repeated up to the data block position at the end of reading. When reading is completed, the memory bitmap is written to the virtual file. As a result, the data block including the read area requested by the user is read on the virtual file, and the corresponding bitmap is updated.

In step 203 of FIG. 2A, the user closes the file. On the other hand, in step (b), the process 208
Is executed and the virtual file is closed.

Next, the reading process (c) from the second time on the same data block by the user operation of FIG. 2A will be described. The user opens the same file. In response to this processing, in the second file control method step 209, the virtual file created at the time of the first reading is opened. Next, when the user makes a read request for the same data block, the processing of FIG. 6 is executed as in (b).

Step 601, CD specified by user
Open the virtual file corresponding to the ROM file,
The bitmap information is stored in the memory 107. First
Similar to the second reading, the block positions at the start and end of the read are calculated, and the process of checking the status of the bitmap is performed. As a result of this processing, the status information table has a record 70
1 is entered in 1 and then the end record 705 comes. This is because the bitmap has changed to all 1's in the first read process. Referring to this table, step 613 is executed. Step 61
In 3, data is read from the virtual file. The virtual file is closed when the user closes the file. This prevents you from reading from a CD-ROM with a slow access speed,
It is possible to read from a virtual file stored on the magnetic disk device. Therefore, the reading speed after the second reading can be increased.

Next, the write operation will be described with reference to FIG. When a write request is issued by the user, it is checked in step 801 whether directory information is stored on the disc. If it is not stored, the directory information is created by the process shown in FIG. 5 in step 806, and the process proceeds to step 802. If already created, the process proceeds to step 802. In step 802, it is checked whether the file designated by the user exists on the CD-ROM. If it does not exist, it is newly created in steps 807 and 808, the directory information and the entry for the file are registered in the virtual file, and the process proceeds to step 804. If the file exists, the file entry on the virtual file is acquired in step 803, and the process proceeds to step 804. Step 8
In 04, the data is written on the virtual file, and then, in step 805, the bitmap information is updated based on the written data, and the process ends.

According to the above embodiment, the read operation and the pseudo write operation are possible.

In this embodiment, the CD-ROM device is 1
Although the case of a stand has been described, it is possible to handle a directory hierarchy composed of a plurality of CD-ROM files by physically connecting a plurality of devices. Therefore, another CD-ROM file structure composed of a plurality of CD-ROMs can be constructed on the magnetic disk device.

[0032]

According to the present invention, since the file data is read from the CD-ROM device and the file is partially copied to the magnetic disk device, the waiting time for writing all the file data can be eliminated. Also, since only the accessed part is always present on the magnetic disk device, there is no unreferenced data and the waste of the disk can be eliminated. When reading data, when the data is already on the magnetic disk device, It is possible to read in a short time.

When the copied data on the CD-ROM file is on the magnetic disk, the function of reading the data from the magnetic disk is used to rewrite the data on the magnetic disk, so that the CD-ROM is simulated. The same effect as rewriting the file is obtained, and the master CD-R
You can easily edit the OM to build another CD-ROM structure.

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall configuration of a CD-ROM file system.

FIG. 2 is an operation flowchart of a CD-ROM file system.

FIG. 3 is an explanatory diagram of a CD-ROM file.

FIG. 4 is an explanatory diagram of a virtual file.

FIG. 5 is a flowchart of control operation of the CD-ROM file system.

FIG. 6 is a flowchart of the control operation of the CD-ROM file system.

FIG. 7 is an explanatory diagram of a table that stores the status of retrieved bitmap information.

FIG. 8 is a flowchart of a control operation of the CD-ROM file system.

[Explanation of symbols]

101 ... CD-ROM device, 102 ... Controller, 1
03 ... CPU, 104 ... Magnetic disk device, 105 ... Buffer memory, 106, 107, 108, 109 ... Work memory.

Claims (2)

[Claims] 1. In a read-only large-capacity, low-speed access file system such as a CD-ROM, a plurality of CD-ROM devices for storing files and the respective CDs are provided.
-Means for reading data from a ROM device and the CD-
A buffer memory which is a storage area for temporarily storing the data read from the ROM device, a magnetic disk device for copying the read data, and means for constructing a CD-ROM file on the magnetic disk device, Means for accessing a CD-ROM file on the magnetic disk device for each data unit in the buffer memory, and the CD-R on the magnetic disk device in which data is written.
A management table that manages which position of the file corresponding to the CD-ROM is stored in the OM file, and indicates whether the data exists only on the CD-ROM or whether there is copy data on the magnetic disk device; The management table comprises means for determining whether the read destination of data is a file on the magnetic disk device or a file on the CD-ROM device. For reading operation, the CD-ROM is stored on the magnetic disk device. By partially copying the above file data, the write time to the magnetic disk device is shortened and a large capacity, the same file is accessed to a low speed access device at a high speed. Data is written on the magnetic disk unit, and the data for the written data position has already been written on the magnetic disk. To be present on the device, by rewriting the management information, file control method, characterized in that the read only the CD-ROM file can simulates a read-write file. 2. The means for constructing the CD-ROM file on the magnetic disk device according to claim 1,
Another CD-R composed of the plurality of CD-ROM files is created on the magnetic disk device by creating a directory hierarchical structure composed of the plurality of CD-ROM files.
A file control method for constructing and editing OM files.