JPH04205360A - Filing system - Google Patents

Abstract

PURPOSE:To prevent system information from being destroyed due to the disconnection of a power source by erasing update information stored in a persistent storage means after updating the system information. CONSTITUTION:An update processing means 6 receives the address of information to be updated and the update information of an updating method, etc., from an update instruction means 5, and stores the update information in a battery-backed up update information storage means 7 prior to the execution of update processing, and after that, executes the update processing of the system information. When the update processing is interrupted by the disconnection of the power source, the update information can be held with the update information storage means safely even after the power source is disconnected. In the case, it is possible not only to decide whether or not the update processing is interrupted, but to continue the update processing after restart up of a system. Thereby, the system information can be prevented from being destroyed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a file system for managing files such as image information stored in a storage device, and more particularly to updating system information in the file system.

[Background of the Invention] In a file system that manages files such as image information stored in a storage device, it is important to update system information for managing files in accordance with the status of the storage device. .

Such system information includes a file allocation table (hereinafter abbreviated as rFATJ) and a directory (DIR).

FAT manages the arrangement of file data on the storage device in memory block units, and DIR manages the arrangement of file data on the storage device in memory block units, and DIR manages the arrangement of file data on the storage device,
It consists of management information such as file name, file size, creation/update date, etc., and a start pointer indicating the address of the first block where file data is stored.

As mentioned above, system information that shows the relationship between data stored in the storage device and the status of the entire file system is
For example, if a file system is destroyed due to a power outage, the overall operation of the file system will become abnormal, and the symptoms will gradually worsen and eventually become a fatal problem.

FIG. 5 is an explanatory diagram showing updating of system information when creating a directory.

For directory generation, create a new directory area and free block, for example 100OH (H indicates hexadecimal number)
get. As shown in the figure, the contents of the directory (a) are in an unused state, with FAT corresponding to free block 1000H.
The content of is 0000H indicating free space (FAT
(C) condition).

Next, the contents of the FAT corresponding to block 100OH are changed to FFFFH indicating the end of the file (FAT (d) state), and file data is stored in empty block 1000H. If the file data cannot be stored in block 1000H, the contents of the FAT corresponding to block 100OH are changed to 1o01H, which indicates the next free block (FAT (e) status), and the file is stored in block 100OH.
Indicates that OH continues to 100IH.

FFFF the contents of FAT corresponding to block 100IH
H (state of FAT())) and stores the overflow file data in block 100LH. block 10
If it cannot be stored in 0LH, block 100IH
Change the contents of the FAT corresponding to FFFFH to 1003H, which indicates that it continues to the next free block 1003H (
In addition, change the FAT contents corresponding to PRO 100BH to FFFFH (FAT status Ig), and transfer the overflow file data to PRO 100BH.
Stored at 00:3H. When all the file data is stored, the update of the contents of the FAT is completed, and the correspondence between the memory block arrangement W(su) and the FAT(chi) on the storage device becomes as shown in the figure.

The contents of the directory (N) now include management information such as the file name and creation date and time, and the head pointer 100OH indicating the address of the head memory block.

The above is the operation when directory generation is performed normally. For example, if directory generation processing is interrupted due to a power outage between FAT (e) and (e), then FAT
remains in the state (e).

Since the content of FAT (E) is 100IH, the data stored in block 100OH is block 100LH.
It follows. On the other hand, since the contents of the FAT corresponding to block 100LH are 0000H, block 100IH is an empty block.

If an inconsistency occurs in the FAT contents due to a power outage, if block 1001H is allocated as a block for another file during subsequent directory creation, a problem will occur in which the data stored in block 100IH will belong to two files. .

[Problem to be solved by the invention] System information is not destroyed during normal operation, but as mentioned above, an abnormality may occur in system information due to a power failure due to a power outage or erroneous operation while updating system information. .

Conventional countermeasures against this problem are as follows.

(1) Destruction of system information is detected by error detection means such as a checksum.

(2) The hardware is refined so that even after power is turned off, power continues to be applied for the time required to update system information without contradiction.

Here, the disadvantage of method (1) is that although it is possible to detect abnormalities in system information, it is difficult to restore them normally, and as a result, part or all of the file system must be reinitialized, so the stored This means that valuable data will be lost.

In addition, the disadvantage of method (2) is that although no abnormality occurs in the system information, if the data is stored in a low-speed device such as a magnetic storage device, the time required for updating is several orders of magnitude.
This can extend to 0.00 milliseconds, making the hardware expensive.

Therefore, in order to solve the above-mentioned problems, the present invention proposes a file system that uses inexpensive hardware and does not cause abnormality in system information due to power interruption.

1. Means for Solving the Problems In order to solve the above problems, the present invention provides a permanent storage means for storing updated information regarding system information.

an update processing means for updating system information based on update information stored in a durable storage means, and for continuing updating system information after restarting if the update is interrupted due to a power outage; and updating system information. 6. In this invention, apart from the memory area in which system information is stored, the battery is A backed-up update information storage means 7 is provided, and when updating system information, the update information supplied from the update instruction means 5 to the update processing means 6 is stored in the update information storage means 7, and then the update information is sent to the update processing means 6.
The update process is performed by The update information stored in the update information storage means 7 is erased by the eraser 8 after execution of the update process. Therefore, even if the update process is interrupted due to a power failure during the update process, the update information is stored as is in the update information storage means 7 after restart, so the interrupted update process can be continued as necessary, and the power is turned off. System information will not be destroyed due to disconnection.

Example] Next, an embodiment of the file system according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a functional block diagram showing a file system according to the present invention.

In the figure, reference numeral 5 denotes update instruction means for instructing update of system information associated with file creation and deletion in the storage device 20.

The update processing means 6 receives update information such as the address and update method of the information to be updated from the update instruction means 5, and stores the update information in the battery-backed update information storage means 7 before executing the update process. After that, execute the system information update process.

If the update ends normally, this update process is performed in the same way as the example shown in FIG. 5 described above.

On the other hand, if the update is interrupted due to a power cut, unlike the conventional example shown in FIG. Not only can it be determined whether or not the update process has been updated, but it is also possible to continue the interrupted update process after restarting the system if necessary.
Destruction of system information can be prevented.

Reference numeral 8 denotes erasing means for erasing the update information stored in the update information storage means 7 after the update process is completed.

FIG. 2 is a diagram showing how update information is stored in the battery-backed update information storage means 7 as a system information update table 30, and FIG. 3 shows system information update processing using this system information update table 30, That is, this is a flowchart showing the operation of the file system shown in FIG. 1.

First, it is determined whether the system information update table 30 is in use (Step 5TI), and if it is vacant, the right to use the system information update table 30 is obtained (Step 5T).
2) Start the system information update process.

In step ST3, the head pointer of the directory to be updated is stored in the system information update table 30 as the update directory address 32, and the management information of the updated directory is stored as the updated directory contents 33.
It is stored in the system information update table 30 as

In step ST4, the system information update table 3
For example, "directory generation in progress" is set to 0 as the directory update status 31. The directory update status 31 set here includes information indicating whether the directory is currently being updated, and information indicating an update method such as creation, deletion, or rewriting of the directory.

In step ST5, the address 35 of the FAT to be updated is stored in the system information update table 30, and the updated FAT contents 36 are stored in the system information update table 30.
Store in.

In step ST6, system information update table 3
0 as the FAT update status 34, for example, set ``FAT rewriting J.'' The FAT update status 3 set here
4 is composed of information indicating whether or not the FAT is currently being updated, and information indicating an update method such as generation, deletion, or rewriting of the FAT.

After storing the update information 31 to 36 in the system information update table 30 as described above, for example, the FAT stored in the storage device 20 is rewritten in the same manner as before (step ST7). After the FAT rewriting is completed, the FAT update status 34 of the system information update table 30 is cleared (step ST8).

Next, the directory to be updated is rewritten in the same manner as before (step 5T9), and then the directory update status 31 of the system information update table 30 is cleared (step 5TIO).

After executing the above update process, the system information update table 30
(step 5T11) to prepare for the next system information update. Here, step 5TII of releasing the right to use the system information update table 30 substantially corresponds to the function of the erasing means 8 shown in FIG.

Note that the system information update table 30 configured as described above can be used even when there is a plurality of storage devices 2o.

FIG. 4 is a block diagram showing the facsimile machine 1 incorporating the file system shown in FIG.

In the figure, 10 is a CPU that controls the entire facsimile machine, and 11 is a battery backup RAM corresponding to the update information storage means 7 of the first section, which may be configured as part of the RAM 1B.

12 is a ROM for storing system information update processing and control programs, etc.; 13 is a working area for system control updates; This is a RAM that stores data.

Reference numeral 18 denotes a recording unit that receives image information etc. received by the modem NCU 16 via the interface 17 and converts it into images etc.

20 is a storage device for storing image information etc. as a file; 1;
9 is an interface, 21 is an operation/display unit equipped with a keyboard and a display panel, and 22 is the interface.

In the facsimile machine having the above configuration, the CPU 10, battery backup RAM II, 80M12, RAM
13. The storage device 220 constitutes the file system shown in FIG.

Furthermore, as mentioned above, when searching for a free block when writing file data to a memory block, etc., use F.
All you have to do is search for the code (OOOH) that indicates an empty block in AT.In order to speed up this empty block search,
The FAT is divided into multiple unit FATs, and the presence or absence of free blocks in the memory blocks managed by each unit FAT is expressed as 1-bit data.
An empty block search table may be provided for collectively managing T in bitmap format.

Furthermore, in the above explanation, the number of head pointers constituting the directory is one, but for example, image information and its attributes (
By having multiple head pointers corresponding to different data density, encoding method, etc., it is possible to handle multiple types of data in one file, simplifying and speeding up file searches. Good too.

[Effects of the Invention] In the file system according to the present invention configured as described above, the battery-backed update information storage means can be used regardless of power supply interruptions.

Since the updated information when system information is updated is retained, even if the system information update process is interrupted due to a power outage, it can be continued after recovery, and the system information will not be destroyed. This allows you to inexpensively and effectively prevent system information from being destroyed, and also prevent the loss of having to destroy valuable file data.

Furthermore, if a free block search table is provided that collectively manages the file allocation table (FAT) in a bitmap format, file processing can be speeded up.

Furthermore, if you take multiple start address blanks that make up a directory (well, since multiple types of data can be handled in one file, it is possible to speed up file searches.

[Brief explanation of the drawing]

FIG. 1 is a functional block diagram showing a file system according to the present invention, FIG. 2 is a diagram showing a system information update table, and FIG. 3 is a flow chart 1 showing the operation of the file system according to the present invention. FIG. 4 is a configuration diagram showing a facsimile device to which the file system according to the present invention is applied;
The fifth section is a diagram showing a conventional system information update process. 5 Update instruction means 6 Update processing means 7 Update information storage means 8 Erasing means 1O-CPIJ 11 Battery backup RAM 12-ROM 3-RAM 20 Storage device +'----- 30 System information update table Figure 2 System information Flowchart of update process Figure 3

Claims (1)

[Claims] (1) A durable storage means for storing updated information regarding the system information; and the system information is updated based on the updated information stored in the durable storage means, and if the update is interrupted due to a power cut, the system information is restarted. A file system comprising: update processing means for continuing updating system information after startup; and erasing means for erasing updated information stored in the persistent storage means after updating the system information.