JPH0362240A - Picture data file control system - Google Patents

Abstract

PURPOSE:To secure the data on pages obtained before occurrence of a fault by providing a page allocation table in order to control a picture data file for each page. CONSTITUTION:The head FAT address is stored in a page allocation table (PAT) store area 4 to the data on each page of a file. A FAT store area 1, a directory store area 2, and the area 4 are set into a main storage (memory) and an auxiliary storage (disk). The contents of these areas 1 - 4 are updated as necessary. Thus an access is possible to a data file via the designation of pages carried out by the PAT when the data file consisting of each page is written into the auxiliary storage. As a result, the data on pages obtained before occurrence of a fault can be secured at restoration of the fault by disusing the data on the pages obtained at occurrence of the fault if a fault occurs during a data file access.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a file management method in an auxiliary storage device such as a computer or a communication control device. Micro 5oft
This is a summary of the file management method based on the Disk Open-rating System.

In this case, the disk is divided into three areas: FAT (file allocation table) storage area (1), directory storage area (2), and data file area (3). There is a physical one-to-one correspondence with the logical blocks (3k) to (3z) of the file area. One file has one directory in the directory storage area (2).
FAT (lk) corresponding to logical blocks (3k) to (3z) in which file contents are written
~(lz) is linked, and its first FAT address is stored in the directory as the cluster number of (Za+).

Next, the operation will be explained. When writing a new file, first a free directory is searched for in the directory storage area (2) to obtain a free directory. Next, F.A.
By searching T (1), free logical blocks (3k) to (3z) in the data file area (3) are obtained. Then, the content of the file is written in the empty logical block, and the corresponding FAT address is registered as the cluster number of the directory. If the file contents cannot be written in one logical block, the FAT storage area (1) is further searched, an empty logical block is found, the file contents are written, and the FAT storage area corresponding to the logical block written in the previous FAT is written. Link the address of.

In the case of reading, search the specified file name from the directory storage area (2), and search from the cluster number (1).
Logical blocks (3k) to (3z) corresponding to FAT in
Read one of the. If the next FAT is linked to FAT (1) corresponding to the read logical block, the logical block (3) corresponding to the linked FAT is linked.
k) Read the contents of (3z). Reading is performed in this manner. Delete is done in the directory storage area (
2) Search for the directory with the specified file name,
The FAT is detected from the cluster number, and erasing codes are sequentially inserted into the linked FATs, and erasing codes are also inserted into the directory.

(Problem to be Solved by the Invention) Since the conventional file management system is configured as described above, when managing a data file composed of page units such as image data, the concept of page does not exist. , if a specific page cannot be specified and a failure occurs while writing data to the auxiliary storage device, the file itself becomes abnormal and the page salt that was normally written before the failure occurs. There were problems such as the data also becoming abnormal.

This invention was made in order to solve the above-mentioned problems, and it provides an image data file management method that can guarantee the data before the failure occurs without making the file abnormal when a failure occurs. The purpose is to obtain.

[i! Means to solve the problem]

The image data file management method according to the present invention uses a directory for managing files and a file allocation table for managing link information of the file structure, and also manages the structure of each page in units of pages. A page allocation table is provided as additional information for this purpose, and stores the start address of the FAT in page units.

[Effect]

The image data file management method in this invention allows data file access by specifying a page using a page allocation table when writing and managing a data file composed of pages in an auxiliary storage device. By discarding the data of the page at the time of failure when a failure occurs during failure, it is possible to guarantee the data of the page before the failure occurs at the time of failure recovery.

(Example) An example of the present invention will be described below with reference to the drawings. In FIG. 1, (1) is a FAT (file allocation table) storage area, and (2) shows the structure of a directory for managing files. (3) is an area for data files in the disk, which is composed of a plurality of logical blocks, and each logical block is physically associated with a FAT address on a one-to-one basis. (4) is FAT
(Page Allocation Tape) This is a storage area in which the first FAT address of page-based data of a file is stored.

In addition, the FAT storage area (1), directory storage area (2), and FAT storage area (4) are installed on the main memory (memory) and inside the auxiliary storage device (disk), and the contents are updated as necessary. .

Next, the operation will be explained. When creating a new file, first search the directory area on the memory, obtain an empty directory, set a file name to this C file, and place the directory in use.

Next, an empty logical block (a) is acquired and the first page data is written in the corresponding disk area.

FA corresponding to logical block (a) used at this time
The address of T is set as the cluster number in the previously acquired directory on the memory. Furthermore, FFF indicating the last cluster is set in the corresponding FAT storage area on the memory, and FFF indicating the last page is similarly set in the PAT storage area. If one page worth of data cannot be written in one logical block, another empty logical block (b) is acquired and data is continuously written to the corresponding disk area. The above-mentioned FFF is set in the FAT storage area on the memory corresponding to the logical block (b) used at this time, and the FAT corresponding to the logical block (b) is set in the area corresponding to the previous logical block (a). Set the address. After that, when all the data for one page is written to the disk area in the same way, the directory created on the memory is copied to the directory storage area of the disk, and the FAT storage area and FA
The T storage area is also copied to the disk area. If the data of the next page continues, acquire an empty logical block (C) in the same way as the first page, write the first data to the corresponding disk area, and write the FAT on the memory corresponding to the logical block (C). The aforementioned FFF is set in the storage area, and the FAT address corresponding to the logical block (C) is set in the area corresponding to the previous logical block (b). Furthermore, FFF is set in the FAT storage area on the memory corresponding to the logical block (C), and the FAT address corresponding to the logical block (C) is set in the area corresponding to the previous logical block (a). Thereafter, the contents of the FAT storage area on the memory are similarly updated every time data in the page is written to the disk area. When all the data in the page is written to the disk area, the FAT storage area updated on the memory and the FAT storage area are copied to the disk area. When the above processing is completed for the data of the last page, the file is closed and the creation of the new file is finished.

Next, the case of reading a file will be explained. First, the directory storage area is searched, the corresponding directory is read out, and the cluster number is extracted. Next, the link status of the page of the file is examined from the FAT 8 storage area on the memory corresponding to the cluster number, and the FAT address corresponding to the logical block in which the first data of the page to be read is stored is extracted. Thereafter, corresponding logical blocks are sequentially read from the disk area according to the link information of the FAT storage area. If a page is not specified, the logical blocks corresponding to the beginning of the file are sequentially read from the disk area according to the link information in the FAT storage area.

(Effects of the Invention) As described above, according to the present invention, a page allocation table is added to manage image data files on a page-by-page basis, so it is possible to specify a specific page when operating a file. Furthermore, by controlling the timing of copying the contents in memory to the disk, it is possible to guarantee the data up to the page before the occurrence of a failure.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a file management system according to an embodiment of the present invention, and FIG. 2 is a diagram showing a file management system based on MS-005. In FIG. C, (1) is a FAT storage area, (2) is a directory storage area, (3) is a data file storage area, and (4) is a FAT storage area. In addition, the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] In a file management method using an auxiliary storage device, there are directories for managing image data files, and file allocation for managing link information of file configurations.
An image data file management method characterized by providing a table and a page allocation table as additional information for managing the file structure on a page-by-page basis.