JPH0344745A - Assembled type vtoc file control system - Google Patents

Abstract

PURPOSE:To prevent the generation of a useless area by offsetting the increase/ decrease of the size of a subfile caused by updating with control of a dummy area and superscribing the controlled dummy area at its original position. CONSTITUTION:A subfile 4i stored in a substance part 4 of an assembled type VTOC (volume table of contents) file 1 includes a valid area 4i1 and a dummy area 4i2. When a subfile 42, for example, is updated, the subfile 42 is separated from the part 4 by a temporary file production means 6 and used as a temporary file 5. Under such conditions, an updating operation is carried out and a dummy area control means 7 controls a dummy area so that the total size of the updated subfile 42 is equal to the unupdated size. Then the controlled dummy file is superscribed at the position of the original subfile 42 of the part 4 by a temporary file return means 8. Thus the generation of a useless area is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a collective type TOC file management method 2 in an electronic computer system.

[Prior Art] A DASD (direct access storage device) such as a magnetic disk device is generally used as an external Q device in a computer system, and the term file space generally refers to files on a DASD. show.

By the way, each file on DASD is v'FQC (
However, for reasons such as ease of management, each sequential file is treated as a group file and managed as a single file as a collective VTOC file. There are many things.

When managing this type of collective VTOC file, newly created sequential files are stored in the DASD storage area as subfiles, and later any of the subfiles is updated. For updates that do not involve an increase or decrease in the actual content, such as renumbering, updates are performed within the same area, and for other general updates, the updated sequential file is newly created as a subfile in the free space of the DASD. , and the previous subfile was invalidated.

(Problem to be Solved by the Invention) Conventional collective VTOC files are managed as described above, and each time a subfile is updated, the storage area of the previous subfile is invalidated and reused. This results in a lot of wasted space, and the DASD
The disadvantage was that the storage space was very inefficient.

The present invention has been proposed in view of the above points, and its purpose is to provide a collective VTOC file management system that minimizes the generation of wasted areas.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention creates a new temporary file when creating a new file in a collective TOC file management method in which each of a plurality of sequential files is treated as a subfile and managed as a single file. , a temporary file creation means that cuts out a corresponding subfile from the entity part of a set type VTOC file and creates a temporary file when updating, adds a dummy area of an initial value size to the temporary file when creating a new file, and adds a dummy area of an initial value size to the temporary file when creating a new file; A dummy area adjustment method that adjusts the size of the dummy area so that the size of the subfile does not change, and if adjustment is not possible, sets the dummy area size to the initial value size, and a dummy area is added when creating a new file. A temporary file is stored as a subfile in the free space at the rear end of the entity part of the aggregated VTOC file, and when updating, if there is no change in size before and after the update, the temporary file is returned to the original subfile location, If the size increases, set type V
The present invention also includes a temporary file return means for storing a temporary file in a free area at the rear end of the actual part of the TOC file.

[Operation] In the collective VTOC file management method of the present invention,
The temporary file creation means creates a new temporary file when creating a new file, and when updating, cuts out a corresponding subfile from the entity part of the set type VTOC file and makes it a temporary file, and the dummy area adjustment means creates a new temporary file when creating a new file. In addition to adding a dummy area of the initial value size, when updating, the size of the dummy area is adjusted so that the size of the subfile before and after the update does not change. At this time, if adjustment is not possible, the size of the dummy area is shortened to the initial value size. The temporary file return means stores the temporary file with a dummy area added as a subfile in the empty area at the end of the entity part of the set type VTOC file when creating a new file, and also changes the size before and after the update when updating. If there is no change, return the temporary file to its original subfile location,
If the size increases, it is stored in the empty area at the end of the entity part of the collective VTOC file.

As a result, as long as the increase or decrease in the size of the subfile due to updating can be offset by adjusting the dummy area, it is possible to overwrite the original position, and the generation of wasted areas can be prevented as much as possible.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

First, prior to explaining the embodiment, the structure of a collective VTOC file will be explained.

FIG. 2 shows an example of the logical configuration of the set type VTOC file 1, which is composed of a VTOC section 2, a pointer section 3, and an entity section 4, and the VTOC 21 of the VTOC section 2 stores the pointer section 3. The subfile pointer 3132 of the pointer section 3 points to the storage location of the corresponding subfile 41, 42 stored in the entity section 4.

In addition, the dummy area size management area 22 of the VTOC unit 2
is a part that holds the initial value of the size of a dummy area added when creating a new area. Note that the initial value of the dummy area is determined in consideration of the fact that if it is too small, it will not be able to absorb changes in file content due to updates, and if it is too large, it will actually reduce the storage area usage efficiency.

FIG. 1 is a block diagram showing an embodiment of the collective VTOC file management method of the present invention. In Figure 1, 3i
(i=l,'l,...) is one of the subfile pointers 31.32 of the pointer section 3 in FIG. 2, and 4i (i=1.2...) is the second This is one of the subfiles 41 and 42 of the entity part 4 in the figure. That is, the subfile pointer 31 consists of a subfile start pointer 3i1, a valid area end pointer 3i2, and a subfile end pointer 3i3, and the subfile 41 consists of a valid area 4i1 and a dummy area 4i2, and the subfile start pointer 3i1 points to the start position of the subfile 41 (the start position of the valid area 4i1), the valid area end pointer 3i2 points to the end position of the valid area 4i1 (the start position of the dummy area 4i2), and the subfile end pointer 313 points to the start position of the subfile 41 (the end position of the dummy region 4i2).

On the other hand, temporary file creation means 6, dummy area adjustment means 7, and temporary file return means 8 are provided as functional parts for creating and updating subfiles 41. Note that 5 is a temporary file created in the process of creating and updating the subfile 41. The functions of each means are as follows.

Temporary file creation means 6: When creating a new subfile 4, a new temporary file 5 is created as an independent file, and when updating, the corresponding subfile 41 is created as an independent file from the entity part 4 of the aggregated VTOC file l. It has a function to cut out the file as a single file and use it as a temporary file 5.

93 area adjustment means 7; When creating a new subfile 41, the dummy area size management area 22 of the VTOC unit 2 is added to the temporary file 5 created by the temporary file creation means 6.
A dummy area 4i2 with the initial size indicated by is added, and when updating, the size of the dummy area 4i2 is adjusted so that the size of the subfile 41 before and after the update does not change, and if adjustment is not possible, the dummy area size management area is added. It has a function of setting the dummy area to the initial value size indicated by 22.

Temporary file return means 8; When creating a new subfile 41, the dummy area adjustment means 7 sends the temporary file 5 to which the dummy area 4i2 has been added as the subfile 41 to the free space at the rear end of the entity part 4 of the aggregated VTOC file 1. When updating, if there is no change in the size of the subfile 41 before and after the update, the temporary file 5 is returned (overwritten) to the original location of the subfile 41, and if the size increases, the entity of the collective VTOC file 1 is returned. It has a function of storing in the empty area at the rear end of the section 4.

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

First, it is assumed that the set type VT6C file I is in the state shown in FIG. 2 at a certain point in time, and a new subfile is created in this state.

In this case, the temporary file creation means 6 creates a temporary file 5, the dummy area adjustment means 7 adds a dummy area of the initial value size, and the temporary file return means 8 creates the entity part 4 of the collective VTOC file, fl. is stored in the free space at the end of the file.

Incidentally, when storing the subfile, the pointer section 3 is naturally set. FIG. 3 shows the state after creating a new subfile 41. A newly created subfile 43 subsequent to /12 is stored in the entity section 4, and a subfile pointer 33 indicating the storage position is added to the pointer section 3.

Next, it is assumed that the subfile 42 is updated in the state shown in FIG.

In this case, the subfile 42 is cut out from the entity part 4 of the collective VTOC file I by the temporary file creation means 6 and made into the temporary file 5, updated in the state of the time file 5, and the dummy IF area adjustment means 7 The effect area is adjusted so that the size of the entire subfile after the update is the same as the size before the update. That is, when the substantial content amount of a subfile decreases due to updating, the size of the dummy area is increased, and conversely, when the actual content amount increases, the dummy area size is decreased.

However, if the size of the dummy area increases beyond the size of the 61 area, adjustment is impossible, so the size of the dummy area is set to the initial value size in preparation for the next update. If the size of the subfile can be made equal before and after the update by adjusting the size of the short area, the temporary file return means 8 overwrites the original subfile 42 in the entity section 4. Therefore, the collective VTOC file l
The situation is the same as in Figure 3, and there is no waste area.
However, if adjustment is not possible due to the dummy area, the overall size will increase and the original location cannot be overwritten, so this is unavoidable, and the updated subfile will be the real part 4.
The original subfile 42 is invalidated and becomes a waste area. Figure 4 shows this state, where 42' is the updated subfile, and 42 is the waste 1.
This is a pre-update subfile that was set as the wi area.

〔Effect of the invention〕

As explained above, in the collective VTOC file management method of the present invention, even if subfiles are updated and the actual content increases or decreases, the size of the dummy area can be adjusted as long as it can be absorbed by the dummy Z-area. By adjusting the size of the subfile as a whole, the size of the subfile can be kept constant and the original location can be overwritten, reducing the amount of wasted space and reducing the
This has the effect of greatly increasing the utilization efficiency of the storage area of the ASD.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the collective VTOC file management method of the present invention, and FIGS. 2 to 4 are logical configuration diagrams of the collective VTOC file. In the figure, l・・・・・・・・・・・・Aggregation type VTOC file 2・・・・・・・・・・・・・・・VTOC part 2
l・・・・・・・・・・・・VTOC22・・・・・・
・・・・・・Dago area size management area 3・・・・・・
...... Pointer part 31 to 33... Subfile pointer 4 ...... Substantive part 41 to 43... Subfile

Claims (1)

[Claims] A collective VTO that treats each of a plurality of sequential files as a subfile and manages them as one file.
In the C file management method, a temporary file creation means creates a new temporary file when creating a new file, and cuts out a corresponding subfile from the entity part of a set type VTOC file as a temporary file when updating; A dummy area of the initial value size is added to the dummy area, and when updating, the size of the dummy area is adjusted so that the size of the subfile before and after the update does not change.If adjustment is not possible, the size of the dummy area is set to the initial value size. When a new file is created, a temporary file with a dummy area added is stored as a subfile in the free space at the end of the real part of the collective VTOC file, and when updated, if there is no change in size before and after the update, the temporary file with a dummy area is added as a subfile. Return the temporary file to the original subfile location, and if the size increases, use aggregate VT
A collection type V characterized by comprising a temporary file return means for storing in a free area at the rear end of the entity part of an OC file.
TOC file management method.