JPH03201045A - Data control system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a management method for variable length data, and particularly to a data management method suitable for use in managing hierarchically structured variable length data.

[Prior Art] Conventionally, it has been common practice to store a plurality of variable length data in a storage area of a storage device and dynamically manage these data. However, when trying to manage data dynamically, storage fragmentation can occur.
This causes a problem in that storage space is wasted.

As a conventional technique to solve such problems, for example,
Software Course 21 “Data Structures and Programming (
Written by Toshio Miyaji), Shokodo Co., Ltd. (P.

147-155) and the like are known.

This conventional technique prepares a free list of storage areas and uses this free list to manage data stored in the storage areas.

[Problems to be Solved by the Invention] The above-mentioned conventional technology manages storage areas using a storage area free list, but does not take into consideration securing continuous free space by moving data. First, there is a problem in that it is not possible to secure a large continuous free area.

An object of the present invention is to solve the problems of the prior art described above, to move data without affecting other data, to secure a continuous free space in a storage device, and to prevent storage by fragmentation of the storage area. minimize wasted area, and
An object of the present invention is to provide a data management method that can reduce overhead for searching for free space and managing multiple data.

[Means for Solving the Problems] According to the present invention, the object is to divide a dataset into blocks and obtain block usage information by combining block usage information data of the dataset and area usage information data of the used blocks. , and data control information to avoid updating pointers due to data movement, write data,
At the time of modification, the data in the block is moved to secure free space, and new data is written to that free space. Also, space usage information data for used blocks can be managed collectively in logical units. This is achieved by doing so.

[Operation] When adding data to a logical unit by creating a block of a data set, storing data in the physical block, and managing its usage information in a logical unit,
Since it is possible to obtain usage information inside a physical block of a logical unit without accessing all of the physical blocks of a logical unit, the number of accesses to the physical block can be kept to a minimum, and free space can be The overhead for searching and managing multiple data can be reduced.

[Embodiment] Hereinafter, an embodiment of the data management system according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram illustrating the internal structure of a data set according to an embodiment of the present invention for recording hierarchically structured variable-length data on a magnetic disk, and FIG. 2 is a flowchart illustrating processing operations when adding data. FIG. 3 is a diagram illustrating hierarchically structured data.

In FIG. 1, 1 is a dataset, 2 is a data block, 3 is a data set block usage information storage block, 4 is variable length data, 5 is area usage information in the block, 6
is data control information.

In FIG. 1, data block 2 is one fragment obtained by uniformly dividing data set 1 on the magnetic disk with a fixed length, and one of the fragments is such that each data block 2 in data set 1 It is used as a block usage information storage block 3 that stores information indicating whether or not the block is being used.

Each data block 2 stores therein a plurality of variable length data 4, and also includes area usage information 5 of the data block 2 in which data 4 constituting one node of the hierarchical structure is recorded, and the corresponding Data control information 6, which is position information of data 4 recorded in data block 2, is stored.

The hierarchically structured data stored in each data block 2 of the data set 1 is data provided corresponding to nodes connected in a tree shape, as shown as a data hierarchical structure 7 in FIG. The data corresponding to each node is
Further, as shown in detail as one node 8,
It has a tree-like hierarchical structure. Area usage information 5 of data blocks in which such data within a node is stored is provided for each node as explained in FIG. 1.

Next, a control method according to an embodiment of the present invention when data is added to data block 2 of data set 1 having the above-described configuration will be explained with reference to the flow shown in FIG.

(1) When the data addition process is started and the data is added to the node 8 of the hierarchical structure 7, first, it is prepared corresponding to the node 8 to which the data is added. Referring to the area usage information 5 of the used data blocks for each node, it is determined whether there is any free data block 2 among the data blocks 2 configuring the node (steps 100 to 102).

(2) If it is determined in step 102 that there is an empty data block 2, fill in the empty spaces between the plural data 4 recorded in the data block 2, and collect the data 4 in the data block. Then, a continuous free area is secured, and as the data 4 is moved, the data control information 6, which is the position information of the data 4, is updated (steps 103 and 104).

(3) Furthermore, if it is determined in step 102 that there is no free data block, an unused data block is secured by referring to the block usage information 3 of the data set (steps 105 and 106).

(4) After step 104 or step 106 is completed, data to be added is recorded in the reserved free area or unused data block (step 107).

(5) Thereafter, the area usage information 5 of the usage block for each node is updated, and the data control information 6 is updated, and the process ends (steps 108 and 109).

The operation example of the embodiment of the present invention described above was for adding data to a data set, but when deleting data, it is necessary to update the area usage information 5 of the used block for each node. Just do it.

Furthermore, in the embodiment of the present invention described above, the area usage information 5 of the used block is not provided in each data block,
The reason why the information is provided in units of nodes is to reduce the number of accesses to a recording medium such as a magnetic disk when searching for a free area.

According to the embodiment of the present invention described above, even if the recording position of other data within a data block changes due to the addition of data, it does not affect other data blocks, and the data set is caused by segmentation of the area,
It is possible to eliminate wasted storage space due to fragmentation.

In the embodiment of the present invention described above, the present invention was applied to the management of variable length data having a hierarchical structure, but the present invention can also be applied to the management of ordinary variable length data.

[Effects of the Invention] As explained above, according to the present invention, waste of storage area due to storage area fragmentation can be minimized, and
To search for free space and manage multiple data, information about free space can be obtained without checking all used data blocks, reducing processing overhead and improving system performance. I can do it.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating the internal structure of a data set according to an embodiment of the present invention for recording hierarchically structured variable-length data on a magnetic disk, and FIG. 2 is a flowchart illustrating processing operations when adding data. FIG. 3 is a diagram illustrating hierarchically structured data. 1...Data set, 2...Data block, 3...Data set block usage information storage block, 4...Variable length data, 5...
. . . Intra-block area usage information, 6 . . . Data control information. Figure 1 Figure 2 Figure 3 -11--+1

Claims (1)

[Claims] 1. In a data management method that stores multiple pieces of variable length data in the storage area of a storage device and dynamically manages these data, a data set is divided into multiple data blocks and used to When writing or changing data, the data in the data block is written using the usage information data of the data block, the area usage information data of the used data block, and the data control information indicating the data position within the data block. A data management method characterized by moving data blocks, securing continuous free space within a data block, and writing new data into that free space.