JPS6278638A - File recording and control system - Google Patents

Abstract

PURPOSE:To ensure a quick access to a variable length recording unit by writing the recording unit registered to an index memory to a file after registering it to an idle index memory. CONSTITUTION:When the recording unit is written to a file 3, an index if registered to an index memory 1 is read out. Then the length of the recording unit, the head address, etc., included in said index are stored temporarily in an index memory 2. The memory 2 is searched again by an idle element searching means 5 to detect an idle area suited to the length of the recording unit. Then the recording unit is written to an idle area detected by a writing means 6 and at the same time the information on the length and the head address of said written area are written to the memory 1 as the index information.

Description

[Detailed Description of the Invention] [Summary] In a file recording control method that accesses a readable/writable file using a series of variable-length data as a recording unit, an index memory that stores an index corresponding to a recording unit is used. , a free index memory for storing information regarding the free space of the file, a recording unit reading means for controlling to read and output a predetermined recording unit from the file, and when a desired index to be written is retrieved from the index memory, Register the length of the recording unit included in the index and the start address of the recording unit in the free inch, width, or length memory and search for a predetermined free element, or search for a predetermined free element if the desired index is not searched. A free element searching means for searching for a free element, a writing means for storing a predetermined index in an index memory, and a free index memory updating means, and a recording unit of variable length is used as a unit by using a recording unit reading means and a writing means. I'm trying to access the file.

[Industrial Application Field] The present invention relates to a file recording control method for controlling access to a variable-length series of data (recording unit) for a readable/writable file.

[Conventional technology]

Conventionally, recording units in magnetic disk drives and the like generally have a fixed length, and each unit is assigned an address. but,
Data handled by a computer generally has a variable length. In particular, in word processors, since the number of characters varies from page to page, the maximum value of data for each page is fixed to 4 bytes, for example, and allocated to a magnetic disk device, floppy disk device, etc. as shown in FIG.

[Problem that the invention seeks to solve]

For this reason, as shown in FIG. 6, there is a problem that empty areas are generated between pages, and the memory cannot be used effectively. Furthermore, if the effective data area is compressed and recorded in order to eliminate the free space shown in Figure 6, if characters are inserted in the middle of a page, all data following this effective data area will need to be rewritten. However, there was a problem in that the processing time was slow.

[Means for solving problems]

In order to solve the above problems, the present invention provides an index memory and a free index memory, and for each variable-length recording unit, an identification key for identifying the recording unit, the length of the recording unit, and the recording unit are provided. In addition to storing the start address of the data as an index in the index memory, the length of the free area and the start address are also registered in the free index memory. When reading the desired recording unit, search the index memory. to read a predetermined recording unit from a file, and on the other hand, when writing a predetermined recording unit, for recording units already registered in the index memory, register the area in which this recording unit is stored in the free index memory, and then write the recording unit again. By adopting a configuration in which a predetermined area is secured and written to a file, unused free areas are collectively reconfigured into a large free area in response to writing, thereby making effective use of the memory area.

FIG. 1 shows the basic configuration of the present invention. In the figure, 1 is an index memory, 2 is a free index memory, 3 is a file, 4 is a reading means, 5 is a free element searching means, 6 is a writing means, and 7 is a free index memory updating means.

In FIG. 1, an index memory 1 stores an index. This index is composed of an identification key for identifying a variable length recording unit to be recorded in the file 3, the length of the recording unit, and a start address for storing the recording unit in the file.

The free index memory 2 stores the length of the free area of the file, the starting address, etc.

The file 3 is a readable and writable file configured using a magnetic disk device, a floppy disk device, or the like.

The reading means 4 reads a predetermined recording unit from the file 3 based on a desired index read out by searching the index memory 1, and sends it to the host.

The free element search means 5 searches for a predetermined free area in the file 3 to be written.

The writing means 6 writes a desired recording unit into the free area in the file 3 searched by the free element searching means 5, and also registers the length of the written recording unit, the start address, etc. in the index memory 1. It is.

Free index memory updating means 7 includes writing means 6
The length and start address of a predetermined area in the file 3 written in this area are deleted from the empty index memory 2.

[Effect]

When the configuration shown in FIG. 1 is adopted and a desired recording unit is read from the file 3, the reading j7 means 4 searches the index memory and reads the corresponding index. Next, a desired recording position is read out from the file 3 and sent to the host based on information such as the start address where the recording unit included in the read index is stored and the length of the recording unit.

On the other hand, when writing a recording unit to file 3, the processing differs depending on whether an index identifying the recording unit has already been registered in the index memory.

That is, if an index for identifying the middle recording position has already been registered in the index memory, first, this registered index is read out and the length of the recording unit included in this index is determined. and the start address where the recording unit is stored are temporarily registered in the free index memory 2. Second, free index memory 2
is searched again to find an empty area (empty element) with a length suitable for the length of the recording unit to be written. The first and second processes are performed by the vacant element search means 5. Thirdly, the writing means 6 writes the recording unit into the empty area found in the second step, and also writes information such as the length of the written area and the start address to the index memory 1 as index information.

On the other hand, if the index identifying the recording unit is not registered in the index memory 1, the second and subsequent steps are executed. Then, free index memory updating means 7
However, the area written to the file 3 in the third step is deleted from the free index memory 2.

〔Example〕

FIG. 2 shows the configuration of one embodiment of the present invention, FIG. 3 shows the read flowchart 1, and FIG. 4 shows the write function 1.
FIG. 5 does not show the deleted flowchart. In the figure, 8 represents an identification key register, 9 represents a data length register, 10 represents a control device, 11 represents an I10 sofa memory, and 12 represents an input/output control device. Note that numerals 1 to 3 in the figure have the same effect as those shown in FIG. Further, the dotted line in FIG. 2 represents control, and the solid line represents point I/destination. A detailed explanation will be given below.

In FIG. 2, the indexes stored in the index memory 1 are the identification 1 key (K1), the read flag (f
i), the length of the recording unit (data) (X,), and the start address (a□) of the recording unit in the file 3.

Free elements (free space) to be registered in free index memory 2 are free space lengths L+, ) and file 3.
It consists of the start address (A,) of the free area inside.

The file 3 is a readable and writable file composed of a magnetic disk device, a floppy disk device, and the like. The variable length recording unit written to this file 3 is
Configure the index registered in index memory 1 a, (starting address) and! It is managed by L (length) etc. Furthermore, the free area is the free element Ak stored in the free index memory 2.
It is managed by (starting address), Ll, (length), etc.

The identification key register 8 holds an identification key (index) of input/output data (recording unit to be input/output).

The data length register 9 holds the length of input/output data (recording unit to be input/output).

The control device 10 performs various controls shown using flowcharts to be described later. Note that the components 4.5.6.7 shown in FIG. 1 may be considered to exist as functions within the control device 10.

The I10 expansion memory 11 temporarily holds data when transferring data between the file 3 and the host.

The input/output control device 12 is activated by the control device IO and controls data transfer between the I10 buffer memory 11 and the file 3.

Next, the operation of the configuration shown in FIG. 2 will be explained in detail using FIGS. 3 to 5.

FIG. 3 shows a read flowchart showing a procedure for reading a predetermined recording unit from the file 3 and transferring it to the host.

In FIG. 3, the symbol (■) in the figure indicates the state in which the identification key is placed in the identification key register 8. This means that □ is set in the identification key register 8 as the identification key representing the recording unit (data) to be read.

In the figure, ■ indicates a state in which the index memory 1 is searched to find the identification key.

In the figure, ■ indicates a state in which the read flag f8 is sent to a register not shown.

■ in the figure indicates a state in which data stored in length 18 is read from the starting address ai of the file 3 included in the index found in the index found in the figure, and is transferred to the I10 buffer memory 11. This transferred data is sent to the host.

As described above, a desired recording unit can be read out and transferred to the host based on the index retrieved from the index memory 1.

FIG. 4 shows a write flowchart, showing the procedure for writing the recording unit into the file 3.

In FIG. 4, the symbol (■) in the figure indicates the state in which the identification key is set in the identification key register 8.

In the figure, ■ indicates a state in which the index memory 1 is searched.

In the figure, ■ indicates a state in which it is determined whether or not the identification key Ki exists in the index memory l. If YES,
At ■ in the figure, the read flag f included in the index is reset to a register not shown in the figure, and then at ■ in the figure, a 5-byte area is made available from the start address a of file 3. ).

As a result, the recording unit area stored in the file 3 specified by the identification key Ki is temporarily registered in the free index memory 2. On the other hand, in the case of NO, the identification key is inserted (registered) in the index memory 1 at [phase] in the figure. This means that a newly provided identification key is registered in the index memory 1.

In the figure, ■ indicates a state in which the length l of write data (recording unit) is set in the data length register 9.

In the figure, @ searches for free index memory 2, and Ilk
≧E Indicates a state in which a free area (empty element) with the relationship (1) is found. Here, fk represents the length of the free space registered in the free index memory 2, and l represents the length of the recording unit to be written.

0 in the figure indicates a state in which it is determined whether or not element k exists. This means that it is determined whether there is an empty element k that satisfies the condition expressed by equation (1). If YES, register the start address Ak found from the free index memory 2 at ■ in the figure as the start address ai to be written, and register the length β of the data found from the free index memory 2 at ■ in the figure as the data to be written. length Il
, register as . Then, in [phase] in the figure, the start address and length to be written are deleted from the free index memory 2 as shown in the following formula.

A+l→A3 ・・・・・・・・・・・・(2)L
k-l-4Lk (3) If the answer is NO, the empty areas of the file 3 are consolidated into one location at O in the figure. This is free index memory 2
As a result of the search, element k that satisfies formula (1) was not found, so this means that the storage locations for data (recording units) are reduced so that the free areas in file 3 are consolidated into one location.

In the figure, [phase] indicates a state in which the contents stored in the free index memory 2 are updated. This means that since the free areas are grouped into one place at O in the figure, the start address and length of the free areas registered in the free index memory 2 are rewritten accordingly.

[Phase] in the figure indicates a state in which it is determined whether or not a free space satisfying 2 (11) has been found in the free index memory 2. If YES, the following steps are executed.

If NO, increase the size of file 3 in [Phase] in the diagram.
1 to set the start address a to this value, and then write the data to be written from the I10 buffer memory 11 to the end of the file 3 at ▪ in the figure in such a manner as to add the data to be written. Then, execute the steps below (■) in the figure.

As explained above, when writing, if an identification key for identifying a recording unit is already registered in the index memory 1, the start address a of the recording unit represented by this identification key.

and the length r, are once registered in the free index memory 2, and then a free area (free element) that satisfies formula (1) is found from this free index memory 2, and a recording unit is written in the found free header. Since this control is performed, free areas are consolidated each time a write is performed, and the file 3 is effectively used.

FIG. 5 shows a deletion flowchart showing the procedure for deleting a recording unit.

In FIG. 5, [phase] indicates a state in which the identification key 8 is set in the identification key register 8. In FIG.

In the figure, 0 indicates the identification key K after searching the index memory 1.
, shows the condition of finding an index with .

In the figure, @ indicates a state in which it is determined whether or not an identification key is present. If YES, the length 1. The byte is registered in the free index memory 2, and then the registered element i (index having the identification key Ki) is deleted from the index memory 1 at 3 in the figure.

If no, the process ends.

Using the procedure described above, the deleted recording unit will be registered in the free index memory 2 as a free area.

〔Effect of the invention〕

As explained above, according to the present invention, when an index memory and a free index memory are provided and a recording unit is written, for a recording unit already registered in the index memory, the area in which this recording unit is stored is temporarily made available. After registering in the index memory, a specified area is secured again and written to a file. Therefore, each time a write is made, unused free space is collected and reorganized into a large free space, making the memory area effective. variable length recording units can be accessed quickly.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram of the present invention, FIG. 2 is a configuration diagram of one embodiment of the present invention, FIG. 3 is a read flowchart, FIG. 4 is a write flowchart, FIG. 5 is a deletion flowchart, and FIG. 6 is a deletion flowchart. A diagram illustrating the operation of a conventional file recording control method is shown. In the figure, 1 is an index memory, 2 is a free index memory, 3 is a file, 4 is a reading means, 5 is a free element searching means, 6 is a writing means, and 7 is a free index memory updating means. Patent Applicant Alps Electric Co., Ltd. Patent Attorney Representative Mori 1) Hiroshi (3 others) 4 乍 4 紩ζp 月纪 6m

Claims (1)

[Claims] In a file recording control method in which a readable/writable file is accessed using a series of variable-length data as a recording unit, an identification key for identifying a variable-length recording unit, and a length of the recording unit are provided. , an index memory that stores an index consisting of the start address of the recording unit, a free index memory that stores the free element consisting of the length of the free area of the file, and the start address, and an index memory that stores an index consisting of the start address and the length of the free area of the file. A recording unit reading means for controlling the reading and outputting of a corresponding recording unit from a file based on a desired index; Register the length and the start address of the recording unit in the free index memory and search for a predetermined free element,
Alternatively, a free element search means for searching for a predetermined free element when a desired index is not searched, and a recording unit to be written is written into an area specified by the free element searched using the free element search means, Regarding the writing means that stores the length of the written recording unit and the start address as a predetermined index in the index memory, and the area written by this writing means,
A file recording control method comprising a free index memory updating means for deleting data from a free index memory, and controlling access to a file in units of variable length recording units using a recording unit reading means and a writing means. .