JPH0298752A - Secondary storage area managing system by binary tree - Google Patents

Abstract

PURPOSE:To perform the storage and retrieval processings of lengthy data in a secondary memory device by using a binary tree in the management of a null area in the secondary memory device. CONSTITUTION:The null area is managed by providing entries sorted in sequence of address in the binary tree. A central processing unit 51 searches the entry larger than an address designated in the binary tree and is nearest to the address when an instruction from a main memory device 52 is the one to allocate the area of the secondary memory device 53, and allocates the area, and also, updates the address and size in the entry. When the instruction is the one to release the area, the unit 51 searches the entry having the address adjacent to the designated address, and when it exists, updates the address and the size in the entry, and when no such entry exists, generates the entry having the designated address and size newly, and the management of the null area can be performed at high speed. In such a way, it is possible to perform the storage and the retrieval of the lengthy data at high speed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a storage device and a processing device of an electronic computer.
In particular, the present invention relates to a method for managing data on a secondary storage device used as a database storage means.

C. Prior Art) Regarding methods of managing secondary storage areas when storing data in a database, methods such as linking free areas with pointers and managing them are conventionally known. FIG. 6 is a diagram showing a conventional free space management method using pointer links. 6L 62.63 is free space, 64.65.6
6 indicates a pointer, and an arrow indicates the state of the link.

Furthermore, a method called binary tree is known for the purpose of searching data in a database at high speed.

FIG. 7 is a diagram showing the structure of a binary tree in a secondary storage device. Regarding binary trees, R. Bayer et al.
e 5ysteo+s; 1977 Volume 2 No. 9ll-
(page 26), etc.

[Problem to be solved by the invention]

In multimedia databases, which have been actively developed in recent years, large amounts of variable-length data such as images and text are stored in a database in a secondary storage device. that time,
It is necessary to speed up free space search processing during data storage and to store related data close to each other in order to speed up retrieval of large data.

However, with the conventional secondary storage area management method using pointer links (see Figure 6), when a large amount of long data is stored, it takes time to follow the pointer when searching for free space, and the free space becomes insufficient. There are problems such as it is difficult to arrange related data nearby because they are connected discontinuously, and there is no compatibility with existing image files because pointers are embedded in the file.

On the other hand, conventional binary trees have a key and the address of the record whose value is the key (see Figure 7), and the purpose of this is to quickly search for the record corresponding to the key. No method has yet been proposed for managing free space in secondary storage devices.

An object of the present invention is to provide a method for quickly and efficiently storing and retrieving large amounts of data in a secondary storage device by using a binary tree to manage free space in the secondary storage device. be.

[Means to solve the problem]

In the secondary storage area management method using a binary tree of the present invention, an entry is prepared in the binary tree that describes the address and size of a free area in the secondary storage device, and in the case of area allocation, a specified Searches for an entry with an address close to the specified address, allocates the area, and updates the address and size in the entry. In the case of freeing the area, searches for an entry with an address adjacent to the specified address. If there is one, the address and size in that entry are updated, and if it does not exist, a new entry with the specified address and size is created, resulting in faster management of free space on the secondary storage device. It is characterized by doing.

[Effect]

The present invention solves the problems of the prior art by taking the above-mentioned method. In other words, in order to manage free space by placing entries sorted in address order during binary processing,
New free space can be searched quickly without accessing the actual data side. Furthermore, since a free area with an address close to a specified address can be easily searched for, mutually related data groups can be stored nearby, and large amounts of data can be stored and retrieved at high speed.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a flowchart illustrating an embodiment of the present invention. FIG. 2(a) is a diagram showing the relationship between the binary tree and free area in the secondary storage device, and FIG. 2(b) is a diagram showing an example of the structure of an entry in the binary tree. FIGS. 3 and 4 are diagrams illustrating a binary tree and a secondary storage area after allocating a free area and after releasing the free area, respectively. Further, FIG. 5 is a diagram showing the device configuration of an electronic computer that implements the present invention.

In FIG. 2(a), the hatched area on the left side of the figure is the secondary storage area 3.
Showing free space 23.24.25 in 0, x, y.

2 is its start address. Furthermore, a and b indicate the starting addresses of certain data 26 and 27 that are stored, respectively. The right side of the figure shows the arrangement of entries in the lowest block of the binary tree 31, each with a free area X.

It points to 'l+2. Figure 2(b) shows the structure of one entry (item) 32 in the binary system, where the address is a pointer to a free area, and the size is the size of the free area. The addresses are sorted and stored in ascending order of the addresses shown in FIG. 2(b).

FIG. 3 shows a state after the address a of stored data is specified, a free area is allocated in the vicinity of the address a, and the data is stored, in contrast to the state shown in FIG. 2 <a>.

FIG. 4 shows the state after deleting the data stored at address b and releasing the area, in contrast to the state shown in FIG. 2(a).

Note that although the structure and access method of the binary tree are similar to conventional ones, the contents of entries and the management method are unique to the present invention.

Returning to FIG. 1 again, one embodiment of the method of the present invention will be described using the examples of FIGS. 2 to 4. First, in step 11, the central processing unit 51 in FIG. 5 determines whether the command from the main storage device 52 is to allocate or release an area in the secondary storage device 53. 1
Jump to 7. Here, it is assumed that the instruction has the address and size of the area as information. In step 12, an entry in the binary system is searched for which has an address greater than and closest to the specified address. For example, Fig. 2(a)
In the example, when address a of stored data 26 is specified, the entry with the next address y is found. Next, in step 13, data is written to the address pointed to by the found entry. Step 1
In step 4, it is checked whether the data has completely filled the allocated area.

If there is no remaining data, Ste Nov
The address and size in the Pig entry are updated and the process ends. In the example of FIG. 2(a), the entry corresponding to address y is updated, and as shown in FIG. 3, the address y' of the remaining free area and its size are entered. If there is any remaining data, the entry is removed from the binary tree in step 16 and step 1 is used to search for the next free space.
Return to 2.

If the instruction in step 11 is to release an area, in step 17 an entry having an address adjacent to the specified area is searched in the binary system. In the example of FIG. 2(1), when release of the data area at address b is specified, an adjacent entry with address 2 is found. Next, in step 18, it is checked whether there is an adjacent entry. If there are no adjacent entries, step 19
, create a new ending in binary that corresponds to the liberated area. If an adjacent entry is found,
In step 20, the address and size of the entry is changed in order to combine the free space.

In the example of FIG. 2(a) (similar to step 17), the address of the entry pointing to 2 is changed to b, and the size is changed to the sum of both areas. The results are shown in FIG. Next, in step 21, it is checked again whether there is an adjacent entry. If so, in step 22 those entries are merged to combine the free areas (processing similar to step 20), and step 21 is repeated.

[Effects of the Invention] According to the present invention, the process of searching for free space in a secondary storage device becomes faster and data storage becomes faster, and related data can be stored close to each other, so large amounts of data can be saved. Effects such as speeding up the overall search for data groups that have a relationship with each other can be obtained.

[Brief explanation of the drawing]

Figure 1 is a flowchart showing an embodiment of the present invention, Figure 2 is a diagram showing the relationship between the binary tree and free space in the secondary storage device, and Figure 3 is after the free space is allocated. Figure 4 is a diagram showing the binary tree and secondary storage area after free space is released. Figure 5 is an electronic diagram that implements the present invention. FIG. 6 is a diagram showing a conventional free space management method, and FIG. 7 is a diagram showing the structure of a binary end in a secondary storage device. 23, 24.25...Free area 30...Secondary storage device 31...Binary tree 32...En [...S51...] ... Central processing unit 52 ... Main storage device 53 ... Secondary storage device

Claims (1)

[Claims] (1) Prepare an entry in the binary tree that describes the address and size of a free area in the secondary storage device, and when allocating an area, search for an entry with an address close to the specified address. , allocates the area and updates the address and size in the entry, and in the case of freeing the area, searches for an entry with an address adjacent to the specified address, and updates the address and size in that entry, if any. , and if it does not exist, a new entry with the specified address and size is created, and as a result, the free space of the secondary storage device can be managed at high speed. Storage space management method.