JPS62154149A - Control system for data area allocation of area shared file - Google Patents

Abstract

PURPOSE:To reduce the overhead for security and release of a data area that is caused by the production and deletion of a member, by using an idle logic track control table, a logic track allocating means and a logic track releasing means. CONSTITUTION:When a member is produced, a logic track allocating means 7 is called out to secure a data storing area. The means 7 checks whether an idle logic track is registered or not to an idle logic track control table 9. Then the idle logic track of registered is allocated. While the idle logic track is registered to the table 9 if not idle logic track is registered to the table 9. When the member is deleted, a logic track releasing means 8 is called out. The means 8 traces a chain set between blocks and at the same time sends all logic tracks occupied by the member back to the table 9. When the table 9 is filled, those logic tracks are sent back directly to a bit map 3 for using states of direct logic tracks.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a process for securing and releasing a data storage area, and particularly to a data area allocation control method for creating and deleting a shared area file.

[Conventional technology]

Conventionally, the data area allocation control method for this type of area-shared file was as follows.

(11 The data area in the file is divided into logical tracks consisting of a constant number of consecutive blocks, and the logical track is used as the unit of allocation and release.

(2) Logical tracks within a file are managed using a logical track usage status bitmap (hereinafter abbreviated as LTAM).

(3) When creating a member, whenever an empty logical track is required, an empty logical track is secured by referencing and updating the LTAM and allocated to the member.

(4) When a member is deleted, the logical track occupied by the member is returned to the LTAM so that it can be reused.

[Problem that the invention seeks to solve]

In the conventional data area allocation control method for shared files, the overhead of securing and releasing data areas associated with member creation and deletion is reduced by increasing the size of the logical track. Since the data blocks cannot be used by other members, there is a drawback that the size of the logical track cannot be simply increased in terms of data area usage efficiency.

For example, if there is a variation in the amount of data of individual members, such as large or small amounts of data, it may not be possible to increase the size of the logical track in terms of file space.

Furthermore, since the LTAM is referenced and updated every time a logical track is allocated when creating a member, there is a drawback that when the size of the logical track is made small, the overhead of securing the data area associated with member creation is large.

In view of the above-mentioned points, an object of the present invention is to provide a data area allocation control method for a shared area file that reduces the overhead of securing and releasing data areas associated with member creation and deletion without reducing data area usage efficiency. It is about providing.

[Means for solving problems]

The data area allocation control method for a shared area file of the present invention is such that, in an area shared file whose data area is shared by members each consisting of a plurality of independent data groups, the data area in the area shared file is divided into a constant number of consecutive data areas. A logical track usage status bitmap for dividing the logical track into logical tracks consisting of blocks and managing the usage status of the logical track as a unit for allocating and releasing data areas for the members, and a logical track usage status pinto map. an empty logical track management table in which a section is converted into a memory table; a logical track allocation means for allocating an empty logical track to the member based on the empty logical track management table and the logical track usage status pit map when creating the member; and logical track release means for releasing the logical track occupied by the member based on the empty logical track management table and the logical track usage status map when deleting the member.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

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

The data area allocation control method for the area shared file in this embodiment is as follows: area shared file 1, directory part 2, LTA
M3, a data area 4, a logical track 5, a data block 6, a logical track allocating means 7, a logical track releasing means 8, and an empty logical track management table 9.

The data area 4 in the area shared file 1 is shared by multiple independent data groups (members), and consists of a constant number of consecutive data groups (members).
It is divided into logical tracks 5 each consisting of blocks 6 (7≦4 in this example). This logical track 5 becomes the unit for allocating and releasing the data area 4 to the members.

Member information regarding individual members is stored in the directory section 2. The member information stored in the directory section 2 includes the member name, starting block address, and ending block address.The continuity of the data blocks 6 of each member is from the block with the starting block address to the block with the ending block address. held by a chain. In the example shown in Figure 1, directory section 2
Member M is registered in , and the starting block address of member M is B1, and the ending block address is B14.

The LTAM 3 manages the usage status of the logical track 5 within the file 1. Each bit of the LTAM 3 is associated with each logical track 5 on a one-to-l basis, and when the corresponding logical track 5 is in use, it is expressed as a bit value 0, and when it is not in use, it is expressed as a bit value 1.

In the example of FIG. 1, for example, logical track LT1 is in use, and logical track LT2 is not in use.

The empty logical track management table 9 is for converting a part of the empty logical tracks managed by the LTAM 3 into a memory table. The empty logical track management table 9 is referenced and updated by the logical track allocating means 7 and the logical track releasing means 8 when creating and deleting members. In the example of FIG. 1, logical tracks LT6, LT7, I,
Tl01... is registered as an empty logical track.

Next, the operation of the data head assignment control method for the area shared file of this embodiment configured as described above will be explained.

FIGS. 2(a) and 2(b) are diagrams for explaining data area allocation processing at the time of member creation.

FIG. 2 ta+ shows the state at the start of member creation, and FIG. 2 (bl) shows the 0 state after member creation.

When creating a member, the logical track allocation means 7 is called to secure a data storage area. The logical track allocation means 7 searches the empty logical track management table 9 to see if an empty logical track is registered.

If no empty logical track is registered in the empty logical track management table 9, the empty logical track management table 9
Register an empty logical track in the following steps. First, LTA
M3 is referred to, a bit indicating an empty logical track is searched, and the logical track number corresponding to the corresponding bit is registered in the empty logical track management table 9, and the searched focus on the LTAMU is updated to a bit value indicating in use. do.

This procedure is repeated until the empty logical track management table 9 is filled to complete the registration.

When the registration of an empty logical track on the empty logical track management table 9 is completed or when an empty logical track has already been registered, the logical track allocation means 7 performs 0 creation to allocate one empty logical track for member creation. If the members cannot be stored in one empty logical track, the empty logical track allocating means 7 is repeatedly called, and empty logical tracks are sequentially allocated until the storage of the created members is completed.

For example, when creating member M, logical tracks LTI, LT3, and LTA are selected from the empty logical track management table 9 as the data area of member M (see Figure 2 (a)).
are sequentially allocated, and the empty logical track management table 9 is updated (see Figure 2 (bl)). Along with the creation of member M, the member information of member M is registered in the directory section 2 (see Figure 2 (bl)). ), the directory section 2 is updated.

FIGS. 3 and 3(b) are diagrams for explaining the data area release process when deleting a member.

Figure 3 fal shows the state before member deletion, and Figure 3 (
bl indicates the state after member deletion.

When deleting a member, the logical track release means 8 is called. The logical track release means 8 returns all the logical tracks occupied by the members to the empty logical track management table 9 while tracing the chain between blocks. If the empty logical track management table 9 is full and cannot be returned, the logical track is directly returned to the TAM 3.

For example, when deleting member N, logical track LT2. LT6. LT20. -,
LT98. Release the LT99 (see Figure 3 (al)) and add the empty logical track LT to the empty logical track management table 9.
2. Return LT6 and LT20 (see Figure 3). The empty logical tracks L798, LT99, etc. that cannot be returned because the empty logical track management table 9 is full are directly returned to the LTAM 3 for LTA.

M3 is updated (see Fig. 3 (bl)). Along with the deletion of member N, the member information about member N is deleted from the directory section 2 (see Fig. 3 (bl)), and the directory section 2 is updated. .

The empty logical track management table 9 is taken over in preparation for creation and deletion of multiple members. At the end of all processing for area shared file 1, empty logical track management table 9
All empty logical tracks registered in the LTAM3 are returned to the LTAM3.

〔Effect of the invention〕

As explained above, the present invention uses an empty logical track management table, a logical track allocation means, and a logical track release means, so that the data area that is generated when creating and deleting members can be saved without reducing file space usage efficiency. This has the effect of reducing the overhead of securing and releasing.

Particularly, when the size of the logical track cannot be increased due to variations in the data amount of individual members, the effect of reducing the overhead of securing and releasing data areas associated with creation and deletion in members is significant.

Additionally, when creating and deleting multiple members at once, the logical tracks are stacked in the empty logical track management table, making it possible to process multiple members in one LTAM update, reducing the overhead of securing and releasing data areas. Great mitigation effect.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a diagram showing the configuration of an embodiment of the present invention, and FIG.
l and (L, l are explanatory diagrams of data area allocation processing when creating a member, and Figure 3+al and ('b) are explanatory diagrams of data area release processing when deleting a member. In the figure, 1... Area shared file, 2... Directory part, 3... Logical track usage status Biftmanop (LTAM)
), 4... Data area, 5... Logical track, 6... Data block, 7... Logical track allocation means, 8... Logical track release means, 9... Empty logical track management table It is.

Claims (1)

[Scope of Claims] In an area shared file whose data area is shared by members each consisting of a plurality of independent data groups, the data area in the area shared file is divided into logical tracks each consisting of a constant number of consecutive blocks. A logical track usage status bitmap for managing the usage status of the logical track using this logical track as a unit for allocating and releasing data areas for the member, and a part of this logical track usage status bitmap is converted into a memory table. an empty logical track management table; a logical track allocation means that allocates an empty logical track to the member based on the empty logical track management table and the logical track usage status bitmap when creating the member; A data area allocation control method for a shared area file, comprising: logical track release means for releasing a logical track occupied by the member based on an empty logical track management table and the logical track usage status bitmap.