JPH06236301A - Method for writing data in file - Google Patents

Abstract

PURPOSE:To provide the method which can write the output data of a difference file in secondary storage device without any abnormal ending. CONSTITUTION:When date in an unaltered part of an original file are written, the size of the unaltered part is counted. Then it is decided whether or not the size of the unaltered part can be mapped in a virtual memory at a time. When it is decided that the size of the unaltered part can be mapped in the virtual memory 14 at a time, the unaltered part is mapped in the virtual memory 14 as it is and then the unaltered data are written. When it is decided that the size of the unaltered part can not be mapped in the virtual memory 14 at a time, the size of the unaltered part is divided by (n). Then files of the unaltered parts divided by (n) are mapped in the virtual memory 14 sequentially and then the unaltered data are written.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of writing data to a file using virtual memory.

[0002]

2. Description of the Related Art FIG. 3 is a diagram for explaining a conventional method of writing data to a file. In FIG. 3, the original file 31 includes a plurality of pages 311,
31n, and is stored in a secondary storage device (not shown). Also, the original file 31 can be
Additions, changes, or deletions are made. in this way,
Pages 311 to 3 in the original file 31
Processing such as addition, change, or deletion is performed on 1n. For example, the hatched portions of pages 311 ', 313', and 314 'shown in FIG. 3 indicate that they have been changed.

Generally, when data is written in a file, for example, when data is added, changed, or deleted, an application that manages data between an original file and a difference file has a difference file corresponding to the changed area. Change data is written after expanding 331 and mapping it to a virtual memory (not shown).
Next, the unmodified page 31 of the modified file 32
.., 31n are counted, and the difference file 332 is expanded by the number of pages. Then, when saving the changed file, the expanded difference file 332 is mapped to the virtual memory, and the data of the unmodified portion of the original file is written.

Further, for example, Japanese Patent Laid-Open No. 2-235134.
In the external storage device management method in the publication, a correspondence table between the user identifier determined in the system and the address to the result notification area, which is an area used to notify the requester when the output data writing ends abnormally Is equipped with.
When the data writing to the external storage device fails, the writing end processing result notifying means uses the correspondence table to correspond to the usage identifier of the requester, which is one of the request information managed by the request receiving means. The result notification area is searched, and the requester is notified of the failure. In addition, JP-A-4
The difference management processing method of the load module library with generation described in Japanese Patent No. 52826 can reduce the used capacity of the storage medium by performing difference management of the load module library with generation that can be immediately executed.

[0005]

However, when the size of the unmodified portion of the original file is significantly larger than the size of the remaining virtual memory, it may not be possible to map it to the virtual memory 34. In such a case, since data cannot be written in the difference file, the difference file must be deleted.
For example, in the external storage device management method disclosed in Japanese Patent Laid-Open No. 2-235134, when there is a request for output data that causes the output processing buffer to overflow, a notification of abnormal termination is issued to the requester. That is, there is a problem that the difference file cannot be saved when the notification of abnormal termination is given.

The present invention is intended to solve the above problems, and when the size of the unmodified portion of the original file is larger than the amount left in the virtual memory, the difference file is output without abnormal termination. It is an object of the present invention to provide a data writing method to a file in which the output data of the above can be written in the secondary storage device.

[0007]

In order to achieve the above object, a method of writing data to a file according to the present invention is such that an area of an extension size for generating a difference file by changing data in an original file is mapped to a virtual memory. Then, when writing the data of the unmodified portion of the original file, the size of the unmodified portion of the original file is counted, and it is determined whether the counted size can be mapped to the virtual memory at a time. If it is determined that the size of the unmodified portion can be mapped at one time, it is mapped and written in the virtual memory as it is, and if it is determined that the size of the unmodified portion of the original file cannot be mapped at once, the unmodified portion is The size of 1
/ N, and the divided 1 / n size file is sequentially written to the virtual memory.

[0008]

[Operation] When data is written to the original file, the data in the original file is written after expanding the difference file by the changed area and mapping it to virtual memory. When writing the data of the unmodified portion of the original file, the size of the unmodified portion of the original file is counted. Next, it is determined whether the size of the counted unmodified portion of the original file is mapped into virtual memory at one time. When it is determined that the size of the unmodified portion of the original file can be mapped to the virtual memory at one time, the unmodified portion of the original file is mapped to the virtual memory as it is before the unmodified data is written. If it is determined that the size of the unchanged part of the original file cannot be mapped to the virtual memory at once, the size of the unchanged part of the original file is divided into 1 / n. After that, the unchanged files divided into 1 / n are sequentially mapped to the virtual memory, and the unchanged data are written.

[0009]

[Embodiment] FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, the data writing device performs an input / output unit 11 including a keyboard for inputting data and a display for displaying the input data, and control for writing the input data in a secondary storage device described later. It comprises a control unit 12, a secondary storage device 13 for storing input data, such as a disk, and a virtual memory 14.

The control unit 12 controls the data writing and control unit 12 and the size counting unit 12 that counts the size of the unmodified portion.
2 and the determination means 123 for determining whether or not the size of the unmodified portion can be mapped at once in the virtual memory.
If the determination unit 123 determines that the size of the unmodified portion cannot be mapped at once in the virtual memory, the dividing unit 124 that divides the size of the unmodified portion and the unmodified portion at the same time , Or a writing unit 125 that sequentially writes the divided portions into the virtual memory 14.
Composed of and.

FIG. 2 is a flow chart for explaining a data writing method which is an embodiment of the present invention. The flowchart shown in FIG. 2 is an example in which the size of the unmodified portion of the original file is S pages, and the method of writing data to the file in this embodiment will be described with reference to FIGS. For example, the user reads the data from the secondary storage device 13 to the display, adds, changes, or deletes the data with the keyboard, and then saves the data of the file in the secondary storage device 13 (step 21).

In response to an instruction from the control means 121, the size counting means 122 counts the size of the unmodified portion of the original file, for example, the unmodified portion for S pages (step 22). The control means 121 expands the difference file by the S pages counted by the size counting means 122 (step 23). Control means 121
Searches for unused contiguous areas in virtual memory 14. Then, the judging means 123 compares the size of the continuous area of the virtual memory 14 with the size of S pages counted by the size counting means 122, and S
It is determined whether pages can be mapped in the virtual memory 14 (step 24).

By the judging means 123, the virtual memory 14
If it is determined that the S pages can be mapped, the S pages are mapped in the virtual memory 14 (step 25). After that, the writing unit 125 writes the data of the unmodified portion of the original file into the virtual memory 14 for S pages under the control of the control unit 121 (step 26). When writing the data for the S pages into the virtual memory 14, the control unit 121 checks whether or not the data is divided into 1 / n by the dividing unit 124 (step 27). When S pages have not been divided by the dividing means 124, that is, when n = 0, the file saving ends (step 28).

At step 24, the judging means 123
However, when it is determined that the S pages cannot be mapped to the continuous area in the virtual memory 14, the dividing unit 124
"1" is added to "n" (step 29). Step 29
, “N” becomes “2”, and the dividing means 124
Divide the S page in half. After that, the process returns to step 24, and the determining unit 123 determines that the S / 2 page is the virtual memory 1
Check whether it can be mapped to the continuous area within 4. The dividing unit 124 tries to divide by adding “1” to “n” until the determining unit 123 can map the continuous area in the virtual memory 14.

When the S page is divided into 1 / n and can be mapped to a continuous area in the virtual memory 14, steps 25 and 26 are executed as described above.
After being mapped to the virtual memory 14, 1 / n of data is written. The control means 121 performs step 2
At 7, it is checked whether "n" is "0".
When “n” is not “0”, the control unit 121 determines “n”.
"1" is subtracted from (step 30). Then, returning to step 25, the S / n page is mapped to the virtual memory 14. The control means 121, until “n” becomes “0”,
This process is repeated. That is, as for the S / n page, the S page is written by mapping and writing n times, so that the saving of the file ends (step 28).

[0016]

As described above, according to the present invention,
Even if the size of the unmodified part is larger than the continuous area in the virtual memory, the size of the unmodified part is divided, and the divided size is repeatedly saved, so that the output data can be stored in the storage device without abnormal termination. Can be written on.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart for explaining a data writing method that is an embodiment of the present invention.

FIG. 3 is a diagram for explaining a method of writing data to a file in a conventional example.

[Explanation of symbols]

 11 ... Input / output 12 ... Control unit 13 ... Secondary storage device 14 ... Virtual memory 121 ... Control means 122 ... Size counting means 123 ... Determination means 124 ... Division Means 125 ... Writing means

Claims (1)

[Claims] 1. A method for writing data to a file in which an area of an extension size for generating a difference file due to data change in the original file is mapped to a virtual memory and data of an unmodified portion of the original file is written to the original file. Counts the size of the unmodified portion, determines whether the counted size can be mapped to virtual memory at a time, and if it is determined that the unmodified portion of the original file can be mapped at one time, If it is determined that the size of the unchanged part of the original file cannot be mapped at one time by mapping to the virtual memory and writing, the size of the unchanged part is divided into 1 / n, and the divided 1 / n size A method for writing data to a file, which comprises sequentially writing the file to a virtual memory.