JPS63137338A - File control system - Google Patents

Abstract

PURPOSE:To automatically restore a file even if misinterruption of a power supply, system down or the like is generated by providing each block in a file with a block header having bits indicating the opened count of the file. CONSTITUTION:The opened count of a file and the end block number EB at the preceding opening time are written in a file lable FL and the individual opened count OC of each block is written in the block header of the block. When the end processing of a file is uncompleted due to the generation of the misinterruption of the power supply, system down or the like, each block header is collated with the file label FL at the time of rising the system newly, the validity of the end block number at the time of opening a file in the preceding output mode is decided and the end block number is automatically updated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention (Field of Industrial Application) The present invention relates to a file management method suitable for managing access to a file having a plurality of blocks.

(Prior art) Conventionally, when a file set in the memory area of a magnetic disk device, etc. is being used, if a power failure or system failure occurs, the file may remain uncompleted. It may become.

Generally, each file has at least an open counter indicating the number of times it was opened in output mode and a file label indicating the number of the last block when opened in output mode the previous time, and data input, data modification, etc. are completed. Sometimes the open counter and the number of the last block are updated, and this process is called file end process.

When the system is started up, if a user starts data entry or other tasks using a file that has not been previously terminated, the data that has already been input to that file may be destroyed. be.

For this reason, files that have not been terminated must be terminated later. This task is called file recovery, but it is extremely difficult for general users.

In other words, this work requires file information such as the type, attributes, and record format of the file that was in use at the time of the accidental power cut or system failure, but this information is completely unnecessary for general work. This is because the information is irrelevant.

Traditionally, most of the file recovery work has been carried out by service engineers who go to the site, which poses the problem of having to interrupt system operations during that time.

(Problems to be Solved by the Invention) The present invention has been made in view of the above circumstances, and is a method for automatically recovering files that have not been terminated due to an erroneous power shutoff or system down. The purpose is to provide a file management method that can perform the following tasks without interrupting system operation.

[Structure of the Invention] (Means for Solving the Problem) In managing access to a file having a plurality of blocks, the present invention provides information for each file at least about the number of times the file has been opened and the number of the last block at the time of the previous open. In addition to providing a file label indicating a number, each block is provided with a block header indicating at least the number of times each block has been opened, and when opening a new file, the number of opens in the block header of each block and the number of opens in the file label are provided. When the final block number of the file label is inappropriate in comparison with the number of opens, the final block number is updated to the correct final block number.

(Function) In the file management method of the present invention, the file label indicates the number of times the file has been opened and the number of the last block at the time of the previous opening, and the block header of each block in the file indicates the individual blocks of that block. The number of times the file has been opened is shown, and if the end of the file is not processed due to an erroneous power cut, system failure, etc., each block header and file label will be saved when starting up a new system. In contrast, the validity of the final block number at the time of opening in the previous output mode is determined and the final block number is automatically updated.

(Example) Hereinafter, details of an example of the present invention will be described based on the drawings.

In this embodiment, each file set in the memory area of the magnetic disk has a plurality of fixed-length blocks.

As shown in FIG. 1, each block is composed of a block header BH and a data area DE, and the block header BH includes bits indicating an open counter OC, an effective size within the block BS, and file identification information FD. . Note that the block header BH is automatically secured as part of the data block when securing the file area.

The open counter OC indicates the number of times the block has been opened in output mode, the block effective size BS indicates the actual data length in the data area DE within the block, and the file identification information FD indicates what file the block belongs to. Indicates whether the person belongs to the group. Note that BL in FIG. 1 indicates the entire length of the block.

Also, the open counter OC, which indicates the number of opens in output mode, is the file label P added to the file.
It is also provided in L.

FIG. 2 is a diagram showing the configuration of a file and a file label FL added to it in this embodiment.

This file consists of 8 blocks,
A file label PL is provided at the beginning of the file.

As shown in Figure 1, each block is provided with bits that indicate the open counter OC and the effective size BS within the block, and the file label FL contains the open counter OC and the last block in the previous output mode. A bit indicating the final block number EB is provided.

In the example of FIG. 2, since the open counter OC on the file label PL is "4", the open counter 0Cr4. It can be seen that the block with is the valid block that was opened last time.

That is, in the example of FIG. 2, blocks up to number "5" are valid blocks, and blocks after number "6" are actually invalid blocks.

On the other hand, the final block number E in the file label PL
Since B is "2", it is actually an invalid block "
6" is contradictory.

Therefore, it can be determined that the previous update process for the file label PL was not performed on this file due to an erroneous power cutoff or system failure. In this case, the correct final block number is corrected to "5".

FIG. 3 is a flowchart showing the detection and recovery process of a file for which termination processing has not been performed due to erroneous power interruption Fli or system down, that is, the file label PL has become abnormal, as described above.

First, it is determined whether the final block number of the file label FL indicates the correct final block. (Step A) In the example of FIG. 2, the final block number on the file label PL is "2", so the number "
Check block 3. At this time, number "3"
Since the open counter OC of this block is "4", it is a valid block, and the value of the final block number EB of the file label PL is determined to be abnormal.

Next, the process moves to reading the next block (step B), and it is checked how many valid blocks whose latest open counter QC is "4" continue.

That is, it determines whether the read block is the block that was opened last time, and then checks the file identification and other information FD of the block to determine its validity (
Step C).

This process is repeated until the correct final block is detected, and at the stage when the correct final block is detected, the process of updating the final block number EB of the file label PL is performed (step D).

Note that the process of updating the file label PL also includes a process of reflecting detailed data of the block on the file label FL using a valid address within the block.

Thus, according to the method of this embodiment, even if a file appears that has not been terminated due to an erroneous power shutoff or system down, the termination process is automatically performed the next time the system is started up, and the file is maintainability is dramatically improved.

The present invention can be widely applied to file management in fixed magnetic disk devices, floppy disk devices, and the like.

[Effects of the Invention] As explained above, in the file management method of the present invention, each block in a file is provided with a block header that includes a bit indicating the number of times the file has been opened. However, files that have not been terminated can be automatically recovered, and there is no need to interrupt system operation.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of blocks in a file in one embodiment of the present invention, FIG. 2 is a diagram showing the configuration of files and file labels in the same embodiment, and FIG. 3 is a diagram showing the configuration of an abnormal file in the same embodiment. 6BH...Block header BL...Block length OC...Open counter BS...Block effective size FD・・・・・・
・File identification information DE...Data area PL...File label EB...Final block pick-up Figure 1 Figure 3

Claims (1)

[Claims] (1) In managing access to a file having multiple blocks, each file is provided with a file label indicating at least the number of times the file has been opened and the number of the last block at the time of the last open, and each block is A block header indicating the number of times each block is opened is provided, and when the file is newly opened, the number of opens in the block header of each block is compared with the number of opens in the file label, and the last block of the file label is A file management method characterized in that when a block number is inappropriate, it is updated to the correct final block number.