JPH0764832A - Multi-extent file system - Google Patents

Abstract

PURPOSE:To realize the mass storage file (multi-extent file), whose capacity exceeds a maximum capacity supported by an operating system, in the user level. CONSTITUTION:File names and capacities (numbers of records) of plural data files 5, 6, and 7 reserved on an external storage device are stored in an area information file 4 as a summary with the same virtual file name. A main program 2 of an application program 1 instructs a subprogram 3 to read/write data from/in the virtual file as a multi-extent file with the virtual file name and a virtual record number as the argument. When the main program 2 instructs to read/write record, the subprogram 3 uses the virtual file name and the virtual record number to retrieve the area information file 4 and specifies pertinent data file and record number to read/write the record.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-extent file system, and more particularly to a multi-extent file system for realizing a large-capacity file (multi-extent file) exceeding the maximum capacity of one file supported by an operating system at a user level.

[0002]

2. Description of the Related Art In the conventional multi-extent file method, when an overflow occurs during writing of a file, the area of the file is automatically expanded by a predetermined capacity by the function of the operating system ("NEC Office processor system 3050
OP software manual ", NEC Corporation, published in December 1987). In the case of this multi-extent file function, the position of the newly secured area is automatically determined by the free area of the magnetic disk device at that time.

Further, since the conventional multi-extent file system is realized by the function of the operating system, it cannot be realized by the computer without the multi-extent file function in the operating system.

[0004]

In the above-mentioned conventional multi-extent file system, an extended area is automatically secured in the free area of the magnetic disk device by the function of the operating system when the file overflows. However, there is a problem that a large-capacity file exceeding the maximum capacity of one file supported by the operating system cannot be realized.

There is also a problem in that the user cannot secure an extended area at a place where he wants to secure the area before the file overflows.

Further, in a computer whose operating system does not have the multi-extent file function,
Naturally, there was a problem that the above functions could not be realized.

In view of the above points, an object of the present invention is to provide a multi-extent file system capable of realizing a large-capacity file (multi-extent file) exceeding the maximum capacity of one file supported by the operating system at the user level. To provide.

[0008]

According to the multi-extent file system of the present invention, a plurality of files secured on an external storage device and in which data is actually stored, and file names and capacities of the plurality of files are stored as a list. Area information storage means, a main program means for instructing the reading and writing of records by regarding the plurality of files as a virtual file having one continuous area and having a capacity equal to the total of the plurality of files, and the main program. And a subprogram means for referring to the area information storage means and specifying one of the plurality of files and the record to read and write the record when the means issues an instruction to read or write the record.

[0009]

The present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the structure of a multi-extent file system according to an embodiment of the present invention. The multi-extent file method of the present embodiment has an application program 1 including a main program 2 and a sub-program 3, an area information file 4,
It is composed of data files 5, 6 and 7.

Referring to FIG. 2, the area information registered in the area information file 4 includes a virtual file name, a device number for each of the data files 5, 6 and 7, a file name and a capacity (the number of records).

Referring to FIG. 3, the subprogram 3 is
It is a program that realizes the virtual file 12 (see FIG. 4), and includes a virtual file processing unit 9 and an area information management unit 10.
And a real file processing unit 11.

The virtual file processing unit 9 uses the virtual file 1
Handles 2 records, and exchanges records with the main program 2.

The area information management unit 10 refers to the area information file 4 and manages which record of which data file 5, 6 and 7 each record of the virtual file 12 is actually stored in. Actual data file 5,
Input / output processing for 6 and 7 is performed by the actual file processing unit 11
Instruct.

The actual file processing unit 11 performs input / output processing for the actual data files 5, 6 and 7 according to an instruction from the area information management unit 10.

Referring to FIG. 4, the virtual file 12 is
Determined by the contents of the area information file 4, the data files 5, 6 and 7 registered in the area information file 4 are connected together in the order in which they are registered, and the capacity of each data file 5, 6 and 7 is increased. It is a virtual multi-extent file that is the total capacity of.

Referring to FIG. 5, the virtual file processing unit 9
The process (1) comprises a virtual file name and virtual record number receiving step 91.

Referring to FIG. 6, the process of the area information management unit 10 is performed by focusing on the first line 101, subtracting the capacity from the virtual record number 102, remaining virtual record number correctness determining step 103, and next line focusing step. 104
And an actual file name identification step 105 and an actual record number identification step 106.

Referring to FIG. 7, the real file processing unit 11
Processing is performed in the real file record access step 111.
Consists of.

Next, the operation of the multi-extent file system of the present embodiment thus constructed will be described.

First, the data files 5, 6 and 7 are secured (allocated) on the magnetic disk device (not shown) as normal files, and their area information is registered in the area information file 4. In this example, as shown in FIG. 2, as a virtual file having a virtual file name FILE, a file name FILEA on the magnetic disk device having the device number 1
And FILEB data files 5 and 6 are secured with a capacity of 200 and 300 records respectively,
File name FILE on the magnetic disk device of device number 2
It is assumed that the C data file 7 is secured with a capacity of 100 records.

When the multi-extent file is used in the application program 1, the main program 2 does not actually perform input / output processing for the data files 5, 6 and 7, but uses the virtual file name FILE and the virtual record number as arguments. Call subprogram 3.

The subprogram 3 is the main program 2
When called by referring to the area information file 4, the virtual record number of the virtual file 12 having the virtual file name FILE and the actual record numbers of the actual data files 5, 6 and 7 are associated as shown in FIG. Then, the input / output processing for the actual data files 5, 6 and 7 is performed.

Specifically, the virtual file processing section 9 receives the virtual file name FILE and the virtual record number from the main program 2 (step 91).

Next, the area information management unit 10 first pays attention to the first line of the same virtual file name FILE of the area information file 4 (step 101), and subtracts the capacity from the virtual record number (step 102). Then, it is determined whether the remaining virtual record numbers are positive (step 103),
If it is positive, the next line of the same virtual file name FILE is focused (step 104), and the control is returned to step 102. If the remaining operation record number is not positive in step 103, the file name of the previous line is set as the actual file name (step 105), and the capacity of the previous line is added to the number of virtual records to obtain the actual record number ( Step 106).

Next, the real file processing unit 11 reads / writes the record of the real record number of the data file 5, 6 or 7 having the real file name (step 111).

For example, when the main program 2 is instructed to read the 500th record of the virtual file 12, the subprogram 3 causes the virtual file processing section 9 to display the virtual file name FILE and the virtual record number 500.
Of the virtual record number of the virtual file 12 by referring to the area information file 4 by the area information management unit 10.
The record of 00 is the record number 30 of the data file 6
Recognizing that the record is 0, the real file processing unit 1
1 reads the 300th record of the data file 6 and passes it to the main program 2.

When the main program 2 is instructed to read the 501st record of the virtual file 12, the subprogram 3 causes the virtual file processing unit 9 to display the virtual file name FILE and the virtual record number 501.
And the record number 501 of the virtual file 12 by referring to the area information file 4 by the area information management unit 10.
Is recognized as the record of the record number 1 of the data file 7, the actual file processing unit 11 reads the first record of the data file 7, and passes it to the main program 2.

By the way, the user can expand or reduce the capacity of the virtual file 12 at any time. That is, the user can expand the capacity of the virtual file 12 by securing a file on the magnetic disk device at any time and registering the area information in the area information file 4 with the same virtual file name FILE. . Further, the capacity of the virtual file 12 can be reduced by deleting or changing the contents of the area information file 4.

Further, the user can use a plurality of virtual files by registering a plurality of virtual file names in the area information file 4.

Further, if the virtual device number can be registered in the area information file 4, the user can use different virtual files by using the same virtual file name under different virtual device numbers.

Each of the measures taken in this embodiment can be realized at the user level (application level) by the standard functions related to the files of the operating system.

[0033]

As described above, the present invention secures the area in which data is actually stored as a normal file,
The file names and capacities of the secured multiple files are stored as a list, and the secured multiple files are regarded as a virtual file that has one continuous area and the capacity is the total of the multiple files. By being able to read and write, there is an effect that a large-capacity file (multi-extent file) exceeding the maximum capacity of one file supported by the operating system can be realized at the user level.

Further, there is an effect that the user can set and use the extension area at a place where the user wants to secure the area before the file overflows.

Further, even if the operating system does not have a multi-extent file function,
The effect is that a multi-extent file can be used.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a multi-extent file system according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of contents of an area information file in FIG.

FIG. 3 is a block diagram showing a functional configuration of a subprogram in FIG.

FIG. 4 is a diagram showing a correspondence between virtual files and data files in FIG.

5 is a flowchart showing the processing of a virtual file processing unit in FIG.

FIG. 6 is a flowchart showing a process of an area information management unit in FIG.

FIG. 7 is a flowchart showing processing of an actual file processing section in FIG.

[Explanation of symbols]

 1 Application Program 2 Main Program 3 Sub Program 4 Area Information File 5, 6, 7 Data File 9 Virtual File Processing Section 10 Area Information Management Section 11 Real File Processing Section 12 Virtual File

Claims (6)

[Claims] 1. A plurality of files secured on an external storage device and in which data is actually stored, area information storage means for storing the file names and capacities of the plurality of files as a list, and the plurality of files. Is a virtual file having one continuous area and having a capacity equal to the total of the plurality of files, and main program means for instructing the reading and writing of records, and the area when the reading and writing of records is instructed by the main program means. A multi-extent file system comprising: a sub-program means for referring to the information storage means and reading and writing by specifying one of the plurality of files and its record. 2. The multi-extent file system according to claim 1, wherein the area information storage means can store a device number together with a file name and a capacity and define a virtual file that extends over a plurality of external storage devices. 3. The multi-extent file system according to claim 1, wherein the area information storage means stores a virtual file name together with a file name and a capacity and can define a plurality of virtual files. 4. The area information storage means includes a file name,
The multi-extent file system according to claim 3, wherein a virtual device number is stored together with the capacity and the virtual file name, and a plurality of virtual files having the same virtual file name can be defined. 5. The multi-extent file system according to claim 1, wherein the external storage device is a magnetic disk device. 6. The virtual program processing unit, wherein the sub-program means transfers records to and from the main program means, and the number of which file each record of the virtual file actually refers to by referring to the area information file means. Area information management unit that manages whether or not the data is stored in the record and that instructs input / output processing for the plurality of files, and an actual file processing unit that performs input / output processing for the plurality of files according to an instruction from the area information management unit. The multi-extent file system according to claim 1, comprising: