JPS6356891A - Data writing method - Google Patents

Abstract

PURPOSE:To protect written data even if a fault such as a power failure takes place on the way of data writing by writing a file name and tentative directory information representing a location of a file area storing the file in the directory area prior to writing of data on the file area. CONSTITUTION:Prior to the writing of a file on a floppy disk 11, a file name and tentative directory information representing the location of the file area 22 storing the file are written on the directory area 20 of the floppy disk 11. Then the file is written on the file area 22 of the floppy disk 11 and after the end of writing, the directory information generated by writing the file is stored in the directory area 20 as the true directory information. Thus, even if a trouble takes place on the way of data writing on an external storage device, reading and editing of the data written so far area applied.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method of writing data to an external storage device.
In particular, the present invention relates to a method of writing data to a floppy disk or the like in which a directory area and a file area are formed.

<Prior art> Normally, the storage area of a disk-type recording medium is divided into a directory area and a file area, and data is stored in the file area for each file, and directory information such as file storage location and file name corresponds to each file. The data is stored in the directory area where the data is stored.

When writing a file, the computer first searches the directory area for an unused directory that corresponds to an unused portion of the file area, and then confirms the starting and ending positions of the unused file area from the information written to this unused directory. After that, data is written from the beginning of the unused file area, and after the data writing is completed, directory information such as the file name, the starting storage position of the file, and the file size is written in the unused directory.

When reading a file from an external storage device, a directory is searched based on the file name, and the desired file is selected from the file area by referring to the directory information stored in the directory and read.

<Problem to be solved by the invention> However, if an accident such as a power outage, inadvertent turning off of the power switch, or pulling out of the disk occurs while data is being written to the external storage device, the data still remains on the disk. Since directory information has not been created, file names, file locations, etc. are unknown. Therefore, after the power is turned on again, the file that was being created when the power was turned off becomes unavailable, resulting in the same state as if the file had not been created.

Therefore, there was a problem in that the file had to be recreated from the beginning.

The present invention has been made in view of the problems of the prior art, and even if an unexpected accident such as a power outage occurs while data is being written to an external storage device, the data written up to that point can be preserved. It is an object of the present invention to provide a highly reliable method of writing data to an external storage device that can perform reading, duplication, etc.

1 is a block diagram showing a computer system according to the present invention, in which 10 is a floppy disk device; 11 is a floppy disk device;
12 is a floppy disk, 12 is a processor, 13 is a program memory, 14 is a keyboard, 16 is a display device, and 18 is a memory (RAM).

Function> Before writing a file to the floppy disk 11, the directory area 20 of the floppy disk 11 is
A file area 22 for storing the file name and the file.
Write temporary directory information indicating the location of .

Thereafter, the file is written in the file area 22 of the floppy disk 11, and after the writing is completed, the directory information generated by writing the file is stored in the BR-1-RE area 20 as true directory information.

<Embodiment> An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a block diagram of a computer system to which the method of writing data to an external storage device according to the present invention is applied.

In the figure, a processor 12 that executes predetermined processing and data input and output, a program memory 13 that stores programs for various processes, and an RA that stores processing results, etc.
M18, a display device 1116, a keyboard 14 for data input, and a floppy disk 1 for storing files.
A floppy disk device 10 for reading and writing data is connected to the floppy disk 1 via a bus.

The storage area of the floppy disk 11 is divided into a directory area 20 and a file area 22 as shown in FIG. 2 (C1), and the directory area 20 is further divided into a predetermined number of directories! It is divided into...

Each directory 20A, 20B...corresponds to each file 31, 32,... created in the file area 22, for example, the created file 3
1, the storage area (start and end positions) of file 31 is the BOE address (start storage position) and E
It is stored as the OE address (final storage location), and the address next to the final address for storing the file 31 is stored in the directory 20A as the EOD address (final data storage location). Further, the file name of the file 31 is also stored in the directory 20A.

File name, BOE address (first storage position), EOD
The address (final data storage location) and EOE address (final storage location) form directory information, and directory information including various other identification information is the directory 20.
It is stored in A.

When reading or editing data in the file 31, it is sufficient to search for the corresponding directory 20A based on the file name and read out each directory information.

Directory information for the file 32 is similarly written in the directory 20B.

The part next to the file 32 in the file area 22 is an unused file area 22A up to the end of the file area 22, but an unused directory 20C corresponding to this unused file area 22A has a predetermined unused directory. Information is stored.

That is, the BOE address (first storage position) and the EOD address (last data storage position N) are the same, and both indicate the last address + 1 address of the storage area that stores file 32, and the EOE address (last storage position) indicates the last address of the file area 22A.

Next, the overall operation of the above embodiment will be explained.

Now, when trying to generate and store a new file 33 (see FIG. 2(c)) in the unused file area 22A in FIG. 2, the operator starts file generation (for example, starts data input) using the keyboard 14. instruct.

As a result, the processor 12 uses the floppy disk 11
Search for an unused directory area with the same BOE address (first storage location) and EOD address (last data storage location) from the directory area of (Step 1)
00).

Next, using the BOE address and EOE address of this unused directory 20C, the unused file area 22A (second
The file shown in FIG. (a) is confirmed and reserved for the file 33 to be created from now on (step 102).

Next, enter the file name and file 33 from the keyboard 14.
When the size of the area to be taken as is input, processor 1
Step 2 creates and outputs temporary directory information.

That is, the processor 12 uses the floppy disk device 1.
0 unused directories! EOD written on J20C
Generates file location information with the address (final data location) set to EOE address (final storage location) + 1, and the BOE address (starting storage location) and EOE address (last storage location) written in an unused directory unchanged. Then, temporary directory information including the file location information, file name, etc. is generated and output, and written to the directory area of the floppy disk 11 (step 104,
Figure 2 (see bl).

Thereafter, when data is input from the keyboard 14, the processor 12 sends the data to the floppy disk device 10 while performing predetermined processing, and directs the data to the floppy disk device 10.
The data is sequentially transferred to the floppy disk 11 from the BOE address (starting storage position) indicated by the temporary directory information.
(step 106). Note that at this time, the processor counts the number of data N.

Then, when the data input using the keyboard 14 is completed and a termination command is given, the processor 12 leaves the file name and the BOE address (starting storage position) written in the unused directory 20G as is, and the EOD address (final data storage position). location) is the BOE address (N+1)
The EOE address (final storage location) is the address obtained by adding (N) to the BOE address.The true directory information containing the information is sent to the floppy disk drive 10, and the contents of the directory 20C of the floppy disk 11 are sent to the floppy disk device 10. Rewrite (step 108, see FIG. 2 (C1)).

Finally, unused file area 22A in directory 20D
The unused directory information regarding ' is written and the processing is ended (step 110).

As a result, even if a problem such as a power outage occurs while writing the file 33 to the floppy disk 11,
Since directory information as an enlarged file 33' (FIG. 2(b)), which is larger than the file 33 being written, has already been written in the directory area 20C,
From the file name of file 33', the corresponding directory 20
C, and referring to the information written as directory 20C1, select file 33' from file area 22.
The location of the data can be specified, and the written data can be edited or read.

In contrast, conventionally there is no step 104 in FIG.
If a problem such as a power outage or an accident occurs during file creation, the location of the file cannot be specified, and it must be assumed that no data has been written.

<Effects of the Invention> As explained above, according to the present invention, even if a trouble occurs while writing data to an external storage device, the data written so far can be read or edited. , it is possible to eliminate the need for troublesome work such as re-creating files.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a computer system to which the present invention can be applied, FIG. 2 is an explanatory diagram showing the memory arrangement of the floppy disk in FIG. 1, and FIG. 3 is a flowchart of the processing of the present invention. 10...Floppy disk device, 11...Floppy disk, 12...Processor, 13...Program memory, 14...Keyboard Patent applicant FANUC Co., Ltd. agent Patent attorney ± 5I Fujichiki Fl Figure 2A 20-- fsL 22--7v il 4 @za = 22A--(live energy M7v il now negative force Fig. 2 (b) 33' Fig. 2 (C)

Claims (1)

[Claims] In a data writing method in which a directory area and a file area are formed in a disk-type external storage medium and data is stored in the file area for each file, prior to writing data to the file area, the data is written in the directory area. Write temporary directory information indicating the file name and the location of the file area that stores the file, then write data to the file area, and then write the real directory information generated by writing the file to the directory area. Features: How to write data to an external storage device.