JP2005038176A - Computer system and file management method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform file restoration based on rollback or roll forward by using only the information inside the file. <P>SOLUTION: The file 4 is provided with a rollback journal area 42, a roll forward journal area 43, and data backup area 44 in addition to a data area 41. A file management part 6 copies the contents of the data area 41 to the data backup area 44 when establishment of a quiescent point is required from a program 5, and in data updating by the program 5, a journal before the update and that after the update are stored in the rollback journal area 42 and the roll forward journal area 43. Therefore, even if the file 4 is moved to another computer, restoration processing by the rollback and the roll forward can be carried out only by the information inside the file 4 in the computer in the file transfer destination. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a computer system and a file management method, and more particularly to a computer system and a file management method for recovering a file using a journal.

In a computer system, when a data file is updated according to the processing result of input data, if the input data has an error, the data file is updated to an incorrect content. For this reason, when it is determined that the data input in the past is incorrect, it is necessary to restore the contents of the data file to the state before the update. Further, when a data file on the recording medium is broken due to a hardware failure or the like, it is necessary to restore the data file to the state before the failure.

FIG. 9 is an explanatory diagram of a conventional method for restoring the contents of the data file to the state before the update when the data file is updated based on erroneous input data. First, when the data a in the data file DF is updated to a ′, the content of a before update is recorded in the journal file BJF before update as a journal before update (step S100), and then the data a in the data file DF is recorded. Is updated to a ′ (step S101). Similarly, when the data b in the data file DF is updated to b ′, the contents of b before the update are recorded in the journal file BJF before update as a journal before update (step S102), and then the data in the data file DF is recorded. b is updated to b '(step S103). When the data file DF is restored to the state before the update because the update of the data a and b is based on erroneous input data, the pre-update journal (b, a recorded in the pre-update journal file BJF) ) Is used to restore the data file DF to the state before the update (step S104). The process of restoring the data file DF using the pre-update journal in this way is called rollback.

FIG. 10 is an explanatory diagram of a conventional method for restoring a data file to a state before the failure when the data file on the recording medium is broken due to a hardware failure or the like. First, the contents of the data file DF are saved in the save file SF (step S110). The time point at which this evacuation process is performed is called a stationary point. Next, when the data a in the data file DF is updated to a '(step S111), the updated data a' is recorded in the updated journal file FJF as an updated journal (step S112). Similarly, when the data b in the data file DF is updated to b '(step S113), the content of the updated data b' is recorded in the updated journal file FJF as an updated journal (step S114). If the contents of the data file DF are destroyed, first, the contents saved in the save file SF are copied to the data file DF (step S115), and then after the update recorded in the post-update journal file FJF. Using the journal (a′b ′), the data file DF is restored to the latest state before the failure (step S116). The process of restoring the data file DF to the latest state using the post-update journal is called roll forward.

In the conventional computer system, the data file DF, the pre-update journal file BJF, the post-update journal file FJF, and the save file SF are managed as separate files (see, for example, Patent Documents 1 and 2). .
Japanese Patent Laid-Open No. 5-20236 JP-A-10-133927

As described above, in the conventional computer system, the pre-update journal file BJF, the post-update journal file FJF, and the save file SF are managed as files different from the data file DF. When the file DF is transferred to another computer, it is not sufficient to transfer the data file DF to enable file recovery using a journal in the transfer destination computer, the journal file BJF before update, after update The journal file FJF and the save file SF need to be migrated together in some way. However, since each of these files is managed as one file, it is necessary to accurately specify the before-update journal file BJF, the after-update journal file FJF, and the save file SF corresponding to the data file DF. Is big. In addition, it is easy to make a mistake to migrate only the data file DF or only a part of the journal file, resulting in a problem that the file recovery using the journal cannot be performed at all on the data file DF migration destination computer. It was.

The present invention has been proposed in view of such circumstances, and its purpose is to create a file by providing an area for recording journals in the same file in addition to a data area for recording actual data. The file recovery by rollback can be performed only by the information in the file even if it is moved to other than the computer.

Another object of the present invention is to enable roll-forward file recovery using only information in a file even when the file is moved to a place other than the created computer.

Still another object of the present invention is to enable file recovery by rollback and rollforward only with information in the file even when the file is moved to a place other than the computer where it was created.

A first computer system according to the present invention is a computer system including an external storage device that stores a file, a program that performs business processing using the file, and a processing device that includes a file management unit that manages the file. The file includes a data area for storing data output from the program and a rollback journal area for storing a pre-update journal, and the file management unit stores the data output from the program. Data output means for outputting to the data area, journal output means for recording a pre-update journal in the rollback journal area when the data area is updated by the program, and when the data area is updated by the program, the journal Call the output means After the new previous journal is output to the rollback journal area, access management means for performing a process of calling the data output means to output the actual data to the data area, and before the update recorded in the rollback journal area Data recovery means for performing rollback processing for recovering the contents of the data area using a journal.

A second computer system of the present invention is a computer system comprising an external storage device that stores a file, a program that performs business processing using the file, and a processing device that has a file management unit that manages the file. The file includes a data area that stores data output from the program, a roll-forward journal area that stores an updated journal, and a data backup area that stores the contents of the data area, The file management unit includes data output means for outputting data output from the program to the data area, and journal output means for recording an updated journal in the roll-forward journal area when the data area is updated by the program. , The program When the data area is updated, access is performed to call the journal output means and output the updated journal to the roll forward journal area, and then call the data output means to output actual data to the data area. Management means, data saving means for copying the contents of the data area to the data backup area at the time of a quiesce point establishment request from the program, and contents of the data area at the time of establishment of a quiesce point recorded in the data backup area And a data recovery means for performing a roll forward process for recovering the contents of the data area using the post-update journal recorded in the roll forward journal area.

A third computer system of the present invention is a computer system comprising an external storage device for storing a file, a program for performing business processing using the file, and a processing device having a file management unit for managing the file. The file stores a data area for storing data output from the program, a rollback journal area for storing a pre-update journal, a roll-forward journal area for storing a post-update journal, and the contents of the data area. The file management unit includes a data output means for outputting data output from the program to the data area, and a journal before update when the data area is updated by the program. The rollback journal Journal output means for recording in the area and recording the updated journal in the roll forward journal area; and when the data area is updated by the program, the journal output means is called to roll back the pre-update journal and post-update journal. After output to the journal area and the roll forward journal area, access management means for performing processing for calling the data output means and outputting actual data to the data area, and at the time of a quiesce point establishment request from the program, the data Data saving means for copying the contents of the area to the data backup area, rollback processing for restoring the contents of the data area using the pre-update journal recorded in the rollback journal area, and recording in the data backup area Data recovery means for performing roll forward processing for recovering the contents of the data area using the updated journal recorded in the roll forward journal area and the contents of the data area when the quiesce point is established .

According to the first file management method of the present invention, a) a rollback provided in the file when a data update request for the file is received from a program that performs business processing using the file stored in the external storage device. Recording actual data in the data area of the file after recording the pre-update journal in the journal area; b) restoring the contents of the data area using the pre-update journal recorded in the rollback journal area Performing a rollback process.

According to the second file management method of the present invention, a) data provided in the file when there is a request for establishment of a quiesce point for the file from a program that performs business processing using the file stored in the external storage device A step of copying the contents of the area to a data backup area provided in the file; b) when there is a data update request for the data area from the program, an updated journal is stored in the roll forward journal area provided in the file. Recording and outputting actual data to the data area; c) contents of the data area at the time of establishment of a quiesce point recorded in the data backup area and an updated journal recorded in the roll forward journal area To restore the contents of the data area Performing a word processing includes.

According to the third file management method of the present invention, a) data provided in the file when there is a request for establishment of a quiesce point for the file from a program that performs business processing using the file stored in the external storage device A step of copying the contents of the area to a data backup area provided in the file; b) when a data update request for the data area is received from the program, a pre-update journal is stored in the rollback journal area provided in the file. Recording and recording the updated journal in the roll forward journal area provided in the file, and then outputting the actual data to the data area of the file; c) the pre-update journal recorded in the rollback journal area Restore the contents of the data area using D) performing the rollback process, d) using the contents of the data area when the quiesce point recorded in the data backup area is established and the updated journal recorded in the rollforward journal area to Performing a roll forward process to recover.

In the first computer system and file management method of the present invention, a data area for storing data output from a program and a rollback journal area for storing a pre-update journal are provided in one file. When the data area is updated by the program, the pre-update journal is recorded in the rollback journal area. Therefore, when a file is transferred to another computer, not only the actual data but also the pre-update journal is automatically transferred, and the pre-update journal recorded in the rollback journal area on the file transfer destination computer. It is possible to roll back to restore the contents of the data area using.

In the second computer system and file management method of the present invention, in one file, a data area for storing data output from the program, a roll-forward journal area for storing the updated journal, and a data area A data backup area is provided to store the contents of the data area.When a quiesce point is requested from the program, the contents of the data area are copied to the data backup area. Recorded in the roll forward journal area. Therefore, when the file is transferred to another computer, not only the actual data but also the contents of the data area at the time of establishment of the quiesce point and the updated journal are automatically transferred. It is possible to perform roll forward in which the contents of the data area are restored using the contents of the data area stored in the backup area at the time of establishment of the quiesce point and the updated journal recorded in the roll forward journal area.

In the third computer system and the file management method of the present invention, in one file, a data area for storing data output from the program, a rollback journal area for storing a pre-update journal, and a post-update A roll-forward journal area for storing journals and a data backup area for saving the contents of the data area are provided. When a program establishes a quiesce point, the contents of the data area are copied to the data backup area. When the data area is updated, the pre-update journal is recorded in the rollback journal area and the post-update journal is recorded in the rollforward journal area. Therefore, when a file is transferred to another computer, not only the actual data but also the journal before update, the contents of the data area at the time of establishment of the quiesce point and the journal after update are automatically transferred. In the computer, it is possible to perform rollback to restore the contents of the data area using the pre-update journal recorded in the rollback journal area, and the contents and roll of the data area at the time of establishment of the quiesce point stored in the data backup area Roll-forward that restores the contents of the data area using the updated journal recorded in the forward journal area becomes possible.

As described above, according to the present invention, an area for recording a journal is also present in the same file in addition to a data area for recording actual data. Therefore, even when the file is moved to other than the computer on which the file is created, rollback and roll File recovery by forward can be performed only with the information in the file.

Referring to FIG. 1, an example of a computer system to which the present invention is applied includes a processing device 1 including a CPU and a main memory, an external storage device such as a magnetic disk device 2, and a signal line 3 connecting the two. Consists of. The magnetic disk device 2 is provided with a file 4. The processing device 1 refers to and updates the file 4 to execute a predetermined business process, and the program 5 is interposed between the program 5 and the file 4. The file management unit 6 is provided.

The file 4 includes a data area 41, a rollback journal area 42, a roll forward journal area 43, a data backup area 44, and a journal management information area 45. As the file 4, for example, a direct organization file can be used, but a file of another organization method may be used. Moreover, each area | region 41-45 is implement | achieved by allocating a part of record group which comprises the file 4, for example.

The data area 41 is an area for storing actual data output from the program 5, and corresponds to the data file DF in FIG.

The rollback journal area 42 is an area for storing a pre-update journal, and corresponds to the pre-update journal file BJF in FIG.

The roll forward journal area 43 is an area for storing an updated journal, and corresponds to the updated journal file FJF in FIG.

The data backup area 44 is an area for copying the contents of the data area 41 in order to establish a quiesce point (timing for data recovery), and corresponds to the save file SF in FIG.

The journal management information area 45 is an area for storing journal management information output to the rollback journal area 42 and the roll forward journal area 43. As management information, the position where the next pre-update journal is to be output in the rollback journal area 42, the position where the post-update journal is to be output next in the roll forward journal area 43, and the journal output after establishment of the quiesce point are specified. There is information to do. The management information may be stored in the areas 42, 43, 44 in a distributed manner, and the area 45 may be omitted.

As described above, the file 4 is obtained by realizing the conventional data file DF, the pre-update journal file BJF, the post-update journal file FJF, and the save file SF as one file.

The file management unit 6 includes an access management unit 61, a journal output unit 62, a data output unit 63, a data save unit 64, and a data recovery unit 65.

The data output means 63 performs processing for outputting data output from the program 5 to the file 4 to the data area 41.

When the program 5 updates the data area 41 of the file 4, the journal output unit 62 records the pre-update journal in the rollback journal area 42 and records the post-update journal in the roll forward journal area 43. When recording the pre-update journal and post-update journal in each of the areas 42 and 43, the journal management information area 45 is referred to obtain information on the position to be recorded next, and the journal management information is updated after recording. deep.

When the file 4 is updated by the program 5, the access management means 61 first calls the journal output means 62 to output the pre-update journal and post-update journal to the rollback journal area 42 and roll-forward journal area 43, and then outputs the data. The means 63 is called to perform processing for outputting actual data to the data area 41. Further, the access management means 61 performs a process of reading the data in the data area 41 and returning it to the program 5 when a reference request from the program 5 to the file 4 is made.

The data saving unit 64 copies the contents of the data area 41 to the data backup area 44 when the program 5 requests the establishment of the quiesce point of the file 4, and rolls forward the journal before the quiesce point establishment and the journal after the quiesce point establishment. In order to be able to distinguish on the journal area 43, for example, a process of recording the position information of the journal immediately before the establishment of the quiesce point in the journal management information area 45 is performed.

The data recovery means 65 performs processing for recovering the data area 41 of the file 4 to a specific state. Specifically, in the recovery process by rollback, a process of recovering the contents of the data area 41 to the state before update using the journal before update in the rollback journal area 42 is performed. In the recovery process by roll forward, the data saved in the data backup area 44 is restored to the data area 41 and stored in the roll forward journal area 43 based on the quiesce point information managed in the journal management information area 45. The data area is restored to the latest state before the failure using the updated journal.

The access management means 61, journal output means 62, data output means 63, data save means 64, and data recovery means 65 described above can be realized by a CPU and a file management program that constitute the processing apparatus 1. The file management program is provided by being recorded on a computer-readable recording medium such as a semiconductor memory or a magnetic disk. The file management program recorded on the recording medium is read by the CPU that constitutes the processing apparatus 1, and the operation of the CPU is controlled so that the access management means 61, the journal output means 62, and the data output means 63 on the CPU. The data saving unit 64 and the data recovery unit 65 are realized, and each procedure of the file management method according to the present invention is executed by the CPU.

Next, a file management operation in the computer system according to the present embodiment will be described.

FIG. 2 is a flowchart showing a processing flow of the file management unit 6 when a request for establishing a quiesce point for the file 4 is issued from the program 5. When the data saving unit 64 of the file management unit 6 receives a request for establishing a quiesce point for the file 4 from the program 5 (step S1), the contents of the data area 41 of the file 4 are copied to the data backup area 44 (step S2). Information for identifying the journal recorded last in the roll forward journal area 43 at the time of establishment of the quiesce point is recorded in the journal management information area 45 as information relating to the quiesce point (step S3).

For example, as shown in FIG. 3, when a static point establishment request is issued at time T0 when three data of data a, data b, and data c are recorded in the data area 41, data is stored in the data backup area 44. A copy of ac is generated.

FIG. 4 is a flowchart showing a processing flow of the file management unit 6 when a data update request for the file 4 is output from the program 5. When the access management unit 61 of the file management unit 6 receives a data update request for the file 4 from the program 5 (step S11), the access management unit 61 calls the journal output unit 62, and the journal output unit 62 converts the pre-update journal into the rollback journal area. (Step S12). The updated journal is output to the roll forward journal area 43 (step S13). When the journal output process of the journal output means 62 to the journal areas 42 and 43 is completed, the access management means 61 calls the data output means 63 and outputs data to the data area 41 by the data output means 63 ( Step S14).

For example, as shown in FIG. 3, when a request for updating the data a to the data a ′ is issued from the program 5 at the time T1 after the time T0 that is a quiescent point, the file management unit 6 updates the data a. In addition to outputting to the rollback journal area 42 as the previous journal, the data a ′ is output to the roll forward journal area 43 as the updated journal, and the data a in the data area 41 is rewritten to the data a ′. Similarly, when a request for updating data b to data b ′ is issued from the program 5 at a later time T2, the file management unit 6 outputs the data b as a pre-update journal to the rollback journal area 42, and Data b ′ is output as an updated journal to the roll forward journal area 43, and data b in the data area 41 is rewritten to data b ′.

FIG. 5 shows a state in which the file 4 in such a state is transferred to another computer for data transfer. In FIG. 5, reference numeral 1 'denotes another migration destination processing apparatus, and 2' denotes a magnetic disk device connected to the migration destination processing apparatus 1 '. The file 4 stored in the magnetic disk device 2 'has been transferred from the magnetic disk device 2 of FIG. The file 4 includes a rollback journal area 42, a roll forward journal area 43, a data backup area 44, and a journal management information area 45 in addition to the data area 41 for recording actual data. In the migration destination processing apparatus 1 ′, file recovery by rollback and rollforward becomes possible.

FIG. 6 shows the flow of file restoration processing by rollback in the migration destination processing apparatus 1 ′. When receiving a rollback request for the file 4 from an operator or the like, the data recovery means 65 of the file management unit 6 reads one pre-update journal from the rollback journal area 42 of the file 4 (step S21). Reading is performed in the reverse order of the output order to the rollback journal area 42. Next, the contents of the read pre-update journal are written back to the data area 41 (step S23). In the present embodiment, this process is repeated for all the pre-update journals recorded in the rollback journal area 42, and when there is no pre-update journal read from the rollback journal area 42 (YES in step S22), the process is performed. Finish. As another embodiment, the processing may be finished when the pre-update journal designated by the operator among the pre-update journals recorded in the roll-back journal area 42 is rolled back. .

For example, as shown in FIG. 3, when the a and b pre-update journals are recorded in the rollback journal area 42, the data b 'in the data area 41 is written to the data b using the pre-update journal b. Next, the data a ′ is written back to the data a using the pre-update journal a, and the contents of the data area 41 are restored to the pre-update state (data a, b, c).

FIG. 7 shows a flow of processing when the transfer destination processing apparatus 1 ′ needs to perform file restoration by roll forward before establishing a new quiesce point. As a situation where such a file recovery by roll forward is necessary, there is a case where reading / writing to the data area 41 becomes impossible due to a failure of the magnetic head of the magnetic disk device 2 '. In this case, in the present embodiment, if an area other than the data area 41 can be read and written normally, file recovery by rollback is possible.

First, a portion other than the data area 41 of the file 4 is copied to another normal magnetic disk device, and the same file as the copy source file 4 except for the data area 41 is generated on another normal magnetic disk device. (Step S31). Subsequent processing is executed using this copy destination file 4.

First, when the data recovery means 65 of the file management unit 6 receives a roll-forward request for the file 4 from an operator or the like, it confirms that there is still point information in the journal management information area 45 of the file 4, and the data backup area The contents of 44 are copied to the data area 41 (step S32). Next, one updated journal after the establishment of the quiesce point is read from the roll forward journal area 43 of the file 4 (step S33). Reading is performed in the order of output to the roll forward journal area 43. Next, the data area 41 is updated with the read updated journal (step S35). This process is repeated for all the updated journals recorded in the roll forward journal area 43 since the quiesce point is established, and when there are no updated journals to be read from the roll forward journal area 43 (YES in step S34), the process is performed. Finish.

For example, as shown in FIG. 3, when the data a, b, c are saved in the data backup area 44 and the updated journals a ′, b ′ are recorded in the roll forward journal area 43, The contents of the data backup area 44 are copied to the data area 41, and the contents of the data area 41 are restored to the stationary point state (data a, b, c). Next, the data a in the data area 41 is updated to the data a ′ using the post-update journal a ′, and then the data b is written back to the data b ′ using the pre-update journal b ′. The contents are restored to the state before the failure (data a ′, b ′, c).

In the above embodiment, it is configured to support both rollback and rollforward, but may be configured to support only one of them. A block diagram of an embodiment that supports only rollback is shown in FIG. Compared with FIG. 1, the roll forward journal area 43 and the data backup area 44 in the file 4 do not exist, and the data saving means 64 in the file management unit 6 is omitted.

It is a block diagram of an embodiment of the invention. It is a flowchart which shows the flow of a process of the file management part when the still point establishment request | requirement with respect to a file is issued from the program in embodiment of this invention. It is operation | movement explanatory drawing of embodiment of this invention. It is a flowchart which shows the flow of a process of the file management part when the data update request with respect to a file is output from the program in embodiment of this invention. It is a block diagram which shows the state which transferred the file to another computer for data transfer in embodiment of this invention. It is a flowchart which shows the flow of the file recovery process by rollback in the processing apparatus of a transfer destination in embodiment of this invention. It is a flowchart which shows the flow of the file recovery process by the roll forward in the processing apparatus of a transfer destination in embodiment of this invention. It is a block diagram of another embodiment of the present invention. It is explanatory drawing of the conventional file recovery process by rollback. It is explanatory drawing of the conventional file restoration process by roll forward.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1 '... Processing apparatus 2, 2' ... Magnetic disk unit 3 ... Signal line 4 ... File 5 ... Program 6 ... File management part 41 ... Data area 42 ... Roll-back journal area 43 ... Roll forward journal area 44 ... Data backup Area 45 ... Journal management information area 61 ... Access management means 62 ... Journal output means 63 ... Data output means 64 ... Data save means 65 ... Data recovery means

Claims (9)

In a computer system comprising an external storage device for storing a file, a program for performing business processing using the file, and a processing device having a file management unit for managing the file,
The file includes a data area for storing data output from the program, and a rollback journal area for storing a pre-update journal,
The file management unit includes data output means for outputting data output from the program to the data area, and journal output means for recording a pre-update journal in the rollback journal area when the data area is updated by the program. When the data area is updated by the program, the journal output means is called to output the pre-update journal to the rollback journal area, and then the data output means is called to output actual data to the data area. A computer system comprising: access management means for performing processing; and data recovery means for performing rollback processing for recovering the contents of the data area using a pre-update journal recorded in the rollback journal area. In a computer system comprising an external storage device for storing a file, a program for performing business processing using the file, and a processing device having a file management unit for managing the file,
The file includes a data area that stores data output from the program, a roll-forward journal area that stores an updated journal, and a data backup area that stores the contents of the data area.
The file management unit includes data output means for outputting data output from the program to the data area, and journal output means for recording an updated journal in the roll-forward journal area when the data area is updated by the program. When the data area is updated by the program, the journal output means is called to output the updated journal to the roll forward journal area, and then the data output means is called to output actual data to the data area. An access management means for processing; a data saving means for copying the contents of the data area to the data backup area at the time of a quiesce point establishment request from the program; and the quiesce point at the time of establishment of a quiesce point recorded in the data backup area The contents of the data area Computer system; and a data recovery unit for performing rollforward process to recover the contents of the data area using the recorded updated journal Le forward journal area. In a computer system comprising an external storage device for storing a file, a program for performing business processing using the file, and a processing device having a file management unit for managing the file,
The file stores a data area for storing data output from the program, a rollback journal area for storing a pre-update journal, a roll-forward journal area for storing a post-update journal, and the contents of the data area. And data backup area,
The file management unit records data output from the program to the data area, and records the pre-update journal in the rollback journal area when the data area is updated by the program. Journal output means for recording a journal in the roll forward journal area, and when the data area is updated by the program, the journal output means is called to make the journal before update and the journal after update the roll back journal area and the roll forward journal. After output to the area, an access management means that performs processing to call the data output means and output actual data to the data area, and at the time of a quiesce point establishment request from the program, the contents of the data area are backed up. Data saving means for copying to the area, rollback processing for restoring the contents of the data area using the pre-update journal recorded in the rollback journal area, and the quiesce point at the time of establishment of the quiesce point recorded in the data backup area A computer system comprising: data recovery means for performing roll forward processing for recovering the contents of the data area by using the contents of the data area and the updated journal recorded in the roll forward journal area. a) When there is a data update request for the file from a program that performs business processing using the file stored in the external storage device, after recording the pre-update journal in the rollback journal area provided in the file, Outputting actual data to the data area of the file;
b) performing a rollback process for recovering the contents of the data area using the pre-update journal recorded in the rollback journal area;
A file management method comprising: a) When there is a quiesce point establishment request for the file from a program that performs business processing using the file stored in the external storage device, the contents of the data area provided in the file are the data provided in the file. Copying to the backup area,
b) a step of recording the updated journal in the roll forward journal area provided in the file and outputting the actual data to the data area when there is a data update request for the data area from the program;
c) A step of performing roll forward processing for restoring the contents of the data area using the contents of the data area at the time of establishment of the quiesce point recorded in the data backup area and the updated journal recorded in the roll forward journal area ,
A file management method comprising: a) When there is a quiesce point establishment request for the file from a program that performs business processing using the file stored in the external storage device, the contents of the data area provided in the file are the data provided in the file. Copying to the backup area,
b) When there is a data update request for the data area from the program, the pre-update journal is recorded in the rollback journal area provided in the file, and the post-update journal is recorded in the roll forward journal area provided in the file. Outputting the actual data to the data area of the file after recording;
c) performing a rollback process for recovering the contents of the data area using the pre-update journal recorded in the rollback journal area;
d) performing a roll-forward process for restoring the contents of the data area using the contents of the data area at the time of establishment of the quiesce point recorded in the data backup area and the updated journal recorded in the roll-forward journal area ,
A file management method comprising:   A program for causing a computer to execute steps a and b according to claim 4.   A program for causing a computer to execute steps a, b, and c according to claim 5.   The program for making a computer perform step a, b, c, d described in Claim 6.

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