JPH0713833A - Sequential file processing system - Google Patents

Abstract

PURPOSE:To reduce the workload at the time of restoration and shorten the operation time if a sequential file is outputted by mistake. CONSTITUTION:The sequential file processing system consists of an output open processing 30 having data output direction information for managing the forward and backward access directions of a file, primary data start and end position information at the time of the forward access, secondary data start and end position information at the time of the backward access, and a data position setting means 32 which determines which data position information is used, a data access processing 20 having a forward access means 21 which inputs and outputs the sequential file at the time of the forward access, a backward access means 22 which inputs and outputs the sequential file at the time of the backward access, and an end decision means 23 which decides whether the access means 21 and 22 reach the end of the input data or the end position of a data output area, and a data restoring processing 40 having a restoration state decision means 41 which decides a restoration state and a file state changing means 42 which changes the data output direction information 55.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sequential file processing method, and more particularly to a sequential file processing method for recording data in a randomly accessible storage device in a physical order.

[0002]

2. Description of the Related Art A conventional sequential file processing method is, as shown in the configuration diagram of FIG. 2, a data access process 200 and an output open process 3 executed by a program 100.
00, file information 400 and file data section 50
0, the data access processing 200 has a sequential access means 210 and an end determination means 220, and the output open processing 300 has a data end position setting means 310.
have.

Further, the file information 400 after the output processing
End position information of data (hereinafter referred to as End Of D
(data: EOD) 410, and the data portion 500 of the file has an output data area 510 and a data record 520.

In the figure, the chain line arrow connecting the blocks in the block diagram indicates the direction of reference information flow.

In the conventional sequential file processing method, the file data is stored at the start position of the file data section 500 (hereinafter referred to as "Beginning Of File: B").
(Abbreviated as OF) to EOD4 in the file information 400
The valid data is up to the position indicated by 10. That is, the data is always valid from the beginning of the data section.

Then, in the output open processing 300, in order to output the data from the start position (BOF) of the file data part 500, the data end position setting means 310 sets the EOD 410 to the head position of the file data part 500.

Next, the data access processing 200 sequentially outputs the data passed by the instruction of the program 100 by the sequential access means 210 from the position of the EOD 410. The end determination unit 220 determines whether the forward access unit 210 has reached the end of the input data, or has reached the end position of the data output possible area.
Then, the output data area 510 after the output processing is monitored by the data end position determination means 310, and the EOD 41
It matches the physical end position of 0.

[0008]

In the conventional sequential file processing method described above, when data output processing is erroneously performed, the data is always output from the head of the file data section, and therefore new data output processing is performed. There is a drawback that the previous data is overwritten and erased.

Further, if the file information before the data output process is erased, there is a drawback that the amount of work for restoration increases and the restoration time becomes long.

[0010]

According to the present invention, in a sequential file, a forward access direction indicating an output direction for writing from the physical start position of the file to the end position and the physical end position of the file to the start position direction. A data output direction setting means for managing a reverse access direction indicating an output direction to be written to and a data output direction information setting means for indicating the start position of the data of the file when the data is sequentially accessed as the start position and end position of the data. The data start position information and the primary data end position information indicating the end position of the data are used, or the secondary data start position information indicating the start position of the data of the file and the end position of the data 2 indicating the data start position at the time of reverse access. An output open process comprising data position setting means for determining whether to use the next data end position information; When the data output direction information by the force open process indicates the forward access direction, the forward access means for inputting and outputting the forward organized file from the physical start position of the file to the physical end position of the file, and the data output direction information are Reverse access means for inputting and outputting a sequentially organized file from the physical end position of the file toward the physical start position of the file when indicating the reverse access direction, and whether the data input by the normal access means and the reverse access means is completed. Data access processing comprising an end determination means for determining whether or not the end position of the data outputable area is reached; file information after the data output processing to the file and data in the same file next. The recovery information for the file before output processing from the file information after the output processing of Data consisting of a recovery status determination means for determining the status, a file status change means for changing the data output direction information to the previous output data direction information, and a previous data recovery means for recovering the data end position before the output processing And a recovery process.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. The sequential file processing method of the present invention is, as shown in the configuration diagram of FIG. 1, a data access process 20, an output open process 30, a data recovery process 40, a file information 50 and a file data section 6 executed by a program 10.
It consists of zero.

The file information 50 is the primary data start position information (hereinafter, Beginn) at the time of the previous data output process.
ig Of Data 1: abbreviated as BOD1) 51,
Primary data end position information (hereinafter,
End Of Data1: abbreviated as EOD1) 52,
Secondary data start position information (hereinafter, B
(eginnig Of Data 2: abbreviated as BOD2) 53, secondary data end position information (hereinafter referred to as End Of Data 2: EOD2) 54 at the time of data output processing, and a data output direction used to set the data output direction. Information (hereinafter, abbreviated as DIOD) 55.

Further, the file data section 60 is provided with a physical start position of the file (hereinafter referred to as "Beginning Of").
A file area 61 before output processing and a data record 62 before output processing are provided as forward access direction information 71 from File (BOF) 70 to a physical end position of the file (hereinafter referred to as End Of File: EOF). (Omitted)
The reverse access direction information 81 from 80 includes a data area 64 after output processing and a data record 63 after output processing.

Next, the output open processing 30 is performed by DIOD.
Data output direction setting means 31 for setting (55), and B
OD1 (51), EOD1 (52), BOD2 (5
3) and data position setting means 32 for setting EOD2 (54).

The data access processing 20 is a sequential access means 2 for inputting and outputting a sequential organization file from the physical start position 70 of the file to the physical end position 80 of the file.
1 and the reverse access means 22 for inputting and outputting the sequential organization file from the physical end position 80 of the file to the physical start position 70 of the file, and the forward access means 21 and the reverse access means 22 end the input data. This is executed by the end determination means 23 which determines whether or not it has reached the end position of the data output possible area.

The data restoration processing 40 is a restoration state judgment means 41 for judging the restoration state before the output processing from the file information of the current output data and the file information of the previous output data, and the file processing for changing to the previous data output direction information. This is executed by the state changing means 42 and the pre-data position restoring means 43 for restoring the data start position before the output processing and the data end position before the output processing.

The solid arrows connecting the blocks in the configuration diagram show the flow of instructions for processing, and the chain arrows show the flow of information to be referred to.

Next, the operation of this embodiment will be described.

First, when the program 10 is executed, in the output open processing 30, the data output direction setting means 31
Thus, the DIOD (55) is set as the output process in the forward access direction (here, the data writing direction information before the data output process is the reverse access direction information 81). Then, the data position setting means 32
Thus, BOD1 (51) and EOD1 (52) are set in the BOF 70 which is the physical start position of the file data section 60.

In the data access processing 20, the forward access means 21 set by the data output direction setting means 32 in response to the request of the program 10 causes the data area 6 before the output processing.
The data record 62 of 1 is output. As a result, the data area 61 before the output processing is created.

Here, when the program 10 is executed again, in the output open processing 30, first, the data output direction setting means 31 sets it as output processing in the reverse access direction. That is, DIOD, which is the previous output process
Since (55) is set in the forward access direction information 71, it is set in the reverse access direction information 81 here, and BO
D2 (53) becomes the file start position information, and EOD
2 (54) becomes the end position information of the file. And
BOD2 (53) and EO by the data position setting means 32
D2 (54) is set in the EOF 80 which is the physical end position of the file data section 60.

In the data access processing 20, the reverse access means 22 set by the data output direction setting means 31 at the request of the program 10 outputs the data record 63 to the data area 64 after the output processing.

At the time of data output, it is determined whether the reverse access means 22 has reached the end position of the output data area, that is, whether the access position has reached BOD1 (51). When the end position of the output data area has been reached, the reverse access means 22 is notified that the data cannot be output.

Here, when the data output by the program 10 is erroneous and therefore the data before output is restored, first, when a signal for data restoration is output from the host device, In the data restoration process 40, the salvageable data when the restoration judgment processing unit 41 restores the EOD2 (54) which is the file information after the output of the file information 50 and the EOD1 (52) which is the file information before the output. Display the status of. Then, if EOD1 (52) <EOD2 (54), it is determined that the complete recovery of data is possible.

Next, the file status changing means 42 D
The IOD 55 is set to the direction information opposite to the set direction (here, the DIOD 55 is set from the reverse access direction information 81 to the forward access direction information 71).

That is, when inputting and outputting to this file thereafter, BOD1 (51) is referred to as the data start position of the file information 50, and EOD1 (52) is referred to as the data end position information. It has been restored. If EOD1 (52)> EOD2 (54), the previous data position recovery means 43 causes EOD1.
(52) is set to EOD2 (54), which means that the file has been restored.

[0028]

As described above, according to the present invention, when the data output processing is erroneously performed, the output data is output from the direction opposite to the data output position before the output processing. The probability that data will be erased is reduced. That is, there is an effect that the probability that the data before output can be recovered is increased.

Since the data start position, data end position and data output direction before the output processing are held,
When recovering the data before the output processing, the file information before the output processing can be easily created, and the amount of work at the time of recovery and the recovery time can be shortened.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment for realizing the present invention.

FIG. 2 is a configuration diagram showing a conventional example.

[Explanation of symbols]

 10,100 Program 20,200 Data access processing 21,210 Forward access means 22 Reverse access means 23,220 End determination means 30,300 Output open processing 31 Data output direction setting means 32 Data position setting means 40 Data recovery processing 41 Recovery status Judgment means 42 File status change means 43 Previous data position restoration means 50,400 File information 51 Primary data start position information (BOD1) 52 Primary data end position information (EOD1) 53 Secondary data start position information (BOD1) 54 2 Next data end position information (EOD2) 55 Data output direction information (DIOD) 60,500 File data section 61 Data area before output processing 62,63,520 Data record 64,510 Data area after output processing 70 Physical of file start Location (BOF) 71 physical end position of the forward access direction information 80 file (EOF) 81 reverse access direction information 310 data end position setting means 410 data end position information (EOD)

Claims (1)

[Claims] 1. In a sequential file, a forward access direction indicating an output direction for writing from the physical start position of the file to the end position, and a reverse access direction indicating an output direction for writing from the physical end position of the file to the start position. Data output direction setting means for managing the direction, and primary data start position information indicating the start position of the data of the file and the end of the data at the time of forward access as the start position and end position of the data by the data output direction information setting means. The primary data end position information indicating the position is used, or the secondary data end position information indicating the start position of the data of the file and the secondary data end position information indicating the end position of the file are used in the case of reverse access. An output open process comprising a data position setting means for determining whether or not the data by the output open process. When the data output direction information indicates the forward access direction, the forward access means for inputting and outputting the forward organized file from the physical start position of the file to the physical end position direction of the file, and the data output direction information indicate the reverse access direction. At the time of showing, the reverse access means for inputting and outputting the sequential organization file from the physical end position of the file toward the physical start position of the file, and whether or not the data input by the forward access means and the reverse access means is completed, or A data access process comprising an end determination means for determining whether or not the end position of the data outputable area is reached; and the file information after the data output process to the file and the data output process to the same file next. The recovery status judgment that determines the recovery status for recovering the file before output processing from the later file information A data state changing means for changing the data output direction information to the previous output data direction information, and a previous data restoring means for restoring the data end position before the output processing. A sequential file processing method characterized by.