JPH012133A - file management device - 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 method for controlling files in a direct access storage device, and particularly to a method for controlling sequentially organized files.

[Summary of the invention]

Document data files in word processors and text files created by editors are typically sequentially organized files. Since data in document data files and text files is complicated to change, records are added and deleted many times. However, in the case of a sequentially organized file, it is necessary to rewrite the entire file in order to add or delete records, and when creating a word processor or editor, it is necessary to create a program for this purpose. Therefore, there has been a problem in that the productivity of programs such as word processors and editors is low.

The present invention enables changes such as expansion and contraction of records in a sequential file by simply modifying record data in an application program, improving the productivity of programs such as word processors and editors.

[Traditional techniques]

When processing data using a computer, it is necessary to design an optimal file according to the type of data to improve data processing efficiency. Files are classified into sequential organization files, direct organization files, indexed sequential organization files, segmented organization files, etc., depending on the organization method, but document data and text data handled by word programs and editors have a large amount of data (, Since it is frequently updated, it is usually stored in sequential files.Sequential files are suitable for storing large amounts of data on volumes such as magnetic disks and floppy disks.

FIG. 6 shows a system configuration diagram of a word processor to which a conventional file management device is applied. The CPU 1l is connected to a memory 13 and a console control device 14 via a common bus 12.
, and a disk controller 15 are connected to the console controller 14, and a keyboard 16 and a CRT 17 are connected to the console controller 14, and a magnetic disk 18 and a floppy disk 19 are connected to the disk controller.

When the user enters data from the keyboard 16,
The data is transferred to the CRT1 by the console controller 14.
7 and is also displayed on the CPU 1 via the common bus 2.
Sent to 1. The CPU 1 writes the data to a predetermined area of the memory 13 via the common bus 12. When the user finishes inputting all document data from the keyboard 16 by repeating the above operations, the document data is stored in a predetermined area of the memory 13, and the user issues a command to save the input document data to a file. When input from the keyboard 16, document data is transferred from the memory 13 to the disk controller 15 via the common bus 12 under the control of the CPU II, and the disk controller transfers the document data to the storage device (magnetic disk 1) specified by the command input.
8 or floppy disk 19) (creation of a document file).

The document file created by the word processor as described above is a file whose code is the text data input in one line of the screen on the CRT 17 (until a carry-return is input). Document files are frequently modified and the data length of text data input by the user per line is often different for each line, so they are usually sequentially organized files with variable length records. The user can display and modify the contents of a document file saved on the magnetic disk 18 or floppy disk 19 by inputting a document file modification command from the keyboard 16 on the CRT 17. You can modify document files by adding lines, deleting lines,
This is done by modifying the data in each row. In the case of a sequentially organized file, each record is stored consecutively on the magnetic disk 18 or floppy disk 19, so if a record is added or the data length of a record is changed due to data modification of the document file, the entire file is A rewriting process is performed.

By the way, since the process of rewriting the entire file takes processing time, it is possible to make the document file into a sequential file with fixed-length records, but in that case, even if the data length of one line increases due to data modification, , it is only necessary to rewrite only the records that have changed; there is no need to rewrite the entire file. However, when fixed-length records are used, the utilization efficiency of storage media such as magnetic disks and floppy disks decreases.

[Problem that the invention seeks to solve]

As mentioned above, with conventional file management devices, when the data length of a code changes in a sequential file with variable-length records, it is necessary to execute an application program to rewrite the entire file. . In other words, when creating a program such as a word processor or editor that stores document data or text data in a sequential file of variable-length records and makes changes to each record in that file, the program for changing records is There is a problem in that it is complex and requires a large number of steps, so it takes time to create a program, which reduces productivity.

In view of the above conventional problems, it is an object of the present invention to provide a file management device that increases the productivity of an application program that performs record rewriting processing that involves changing the record length for a sequentially organized file consisting of variable-length records. purpose.

[Means for solving problems]

FIG. 1 is a functional block diagram of the present invention.

Reference numeral 1 denotes a record reading means for reading out a variable length record for which a writing request has been made from a sequentially organized file composed of variable length records containing control information and data stored in a storage medium; 2, reading from the record reading means 1; Comparison means 3 compares the record lengths of the current variable-length record that has been written and the new variable-length record to be newly written; a first creation means for rewriting the control information and data of the current variable length record on the storage medium; 4, the comparison means 2 determines that the new variable length record is longer than the current variable length record; If it is determined that This is the second creation means for writing the writing position of the new variable length record.

[For production]

Now, if a request to write a variable length record of a sequentially organized file is input by executing an application program, the record reading means 1 reads the record number corresponding to the write request from the sequentially organized file on the storage medium. The current variable length record is read and output to the comparison means 2. The comparison means 2 compares the record lengths of the current variable length record and the new variable length record that the application program requests to write, and outputs the comparison results to the first creation means 3 and the second creation means 4. . The first creating means 3 rewrites the control information and data of the current variable length record on the storage medium when the comparison result is a predetermined result. Further, when the second creation means 4 receives a determination result from the comparison means 2 that the record length of the new variable length record is longer than the current variable length record, the second creation means 4 transfers the new variable length record to the storage medium. The above-mentioned current variable-length record is written to a different location from the location where the current variable-length record is stored, and the write location is written to the control information of the current variable-length record on the storage medium. Therefore, even if the record length of a new variable-length record is extended, the writing position of the new variable-length record can be set in the control information of the current variable-length record, and the new variable-length record can be written to that writing position. There is no need to rewrite the entire thing.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram of a system to which an embodiment of the present invention is applied.

The CPU 21 is a central processing unit that executes programs such as word processors and editors stored in a memory 23 such as a RAM (not shown).
ssing Unit), and via the common bus 22, the memory 23, the memory 24, the console control device 25,
It is connected to the disk controller 26.

The console control device 25 echoes back data input from the keyboard 28 and displays it on the CRT 27, converts the data, and outputs the code to the CPU 21 via the common bus 22. Also, under the control of the CPU 21, the memory 23
input the data read from the common bus 22,
Controls such as display on the CRT 27 are performed. The disk control device 26 controls writing of data to the magnetic disk 29 and floppy disk 30, reading of data, etc. based on input/output control commands inputted from the CPU 21 via the common bus 22. In addition, the memory 23 stores programs such as word processors and editors, and
This is a memory that stores input data from the keyboard 28 that is input via the console control device 25 and the common bus 22, and also when starting up a word processor or editor.
Correction data etc. entered by the user from the keyboard on the second day are stored. In addition, document files and text files created by starting a word processor or editor,
When the user inputs a command to save a document file or text file from the keyboard 28, the document file or text file is saved on the magnetic disk 29 or floppy disk 30.

Further, when the user inputs a command from the keyboard 28 to instruct file modification of a document file or text file, the magnetic disk 29 is
Or from the floppy disk 30 to the disk controller 2
6, the corresponding file is read out and stored in the memory 24. Under the control of the CPU 21, the corresponding file is edited into data for screen display, and the contents of the file are displayed on the CRT 27 via the console control device 25.

Next, the magnetic disk 29 or floppy disk 30
The structure of the document file or text file stored in the is shown in FIG. 3 (al, (bl). As shown in FIG. It is composed of a variable length record group 41 and a changed record pool 42. Within the variable length record group 41, variable length records 43 consisting of data of document files and text files are stored in a continuous area.Variable length records 43 is shown in FIG. 3(b).The variable length record 43 is composed of control information 43a, a data area 43b, and a record end delimiter 43C.
Document data or text data displayed on one line of the screen on T27 is stored, and the data length is equal to the data length when first written. Further, at the end of the variable length record 43, a record end delimiter 43C of a predetermined code indicating the end of the variable length record 43 is written.

The control information 43a includes an unchanged flag 44 that indicates whether the valid data of the variable-length record 43 is equal to the data stored in the data area 43b, and a no-change flag 44 that indicates whether the valid data of the variable-length record 43 is equal to the data stored in the data area 43b; Effective data length 4 indicating the data length (number of characters) from the start address of the data
5. It consists of a pointer 46 that indicates the address in the changed record pool 42 where the modified data is written when the data cannot be stored in the data area 43b due to record modification. Note that the no-change flag 44 is set to "0" when the data of the variable-length record 43 is equal to the data stored in the data area 43b;
3 is stored in a part of the data area 43b, it is “1” (shortened), and when the data of the variable length record 43 is stored in the variable length record 43 in the changed record pool 42, it is “1” (shortened). 2” (expansion) is written.

Therefore, the effective data length 45 is valid only when the no-change flag is "1", and the pointer 46 is valid only when the no-change flag is "2". Data in the sequentially organized file 40 such as a document file or a text file is read out via the disk controller 26 and stored in the memory 24 when modifying the file. Editing of the variable length record 43 is also performed in the memory 24. , control information 43a
When the settings, writing of data to the data area 43b, etc. are completed, the variable length record 43 on the memory 24 is written to a predetermined position of the corresponding file on the magnetic disk 29 or floppy disk 30 via the disk controller 26.

Next, the operation of this embodiment configured as above will be explained.

First, the operation of writing data into the sequential organization file 40 will be explained with reference to the flowchart shown in FIG.

This figure is a flowchart showing the record writing operation performed under the control of the CPU 21 when the application program issues an instruction to write a record to the sequential organization file 40. When an application program writes a record, it issues a record write command using the file name, record number, and data of the record to be written as parameters. When the above application program is executed, the CPU
When 21 reads a record write command, it first reads the record (current record) requested to be written by the application program from the corresponding file on the magnetic disk 29 or floppy disk 30 via the disk controller 26 and stores it in the memory 24. (Processing 5T
I).

Then, the data length of the read record is counted (processing 5TI).

Next, data of a new record stored in the memory 23 to be written is transferred to a predetermined area of the memory 24, and further, an area where control information 43a as shown in FIG. 3(b) is written at the beginning of the transferred data. is set, and a record end delimiter 43C is written at the end of the data to create a variable length record (processing 5T2).

Next, the data length of the newly written record created in the memory 24 as described above is counted and compared with the data length of the record counted in the process STI (process 5T3).
. If the data lengths match as a result of the comparison, a new record on the memory 24 is overwritten via the disk controller 26 at the position where the current record of the file is written on the magnetic disk 29 or floppy disk 30 (processing 5).
74).

On the other hand, as a result of the data length comparison, if the data length of the new record is short, the control information 43a of the new record on the memory 24
The no-change flag 44 is set to "1" indicating that the record is shortened, and the data length of the new record is set to the effective data length 4.
5 (processing 5T5). Then, the processing ST
4, a new record on the memory 24 is overwritten via the disk controller 26 at the position of the current record of the file on the magnetic disk 29 or floppy disk 30 (process 5T5).

Further, if the data length of the new record is longer than the current record, control information 43a of the new record on the memory 24
"2" indicating expansion of the record is set in the no-change flag 44, and the start position of the empty area of the changed record boolean 42 is set in the pointer 46 (processing 5T6). and,
Only the control information 43a of the new record is sent to the disk controller 2.
6, the control information 43a of the current record of the file on the magnetic disk 29 or floppy disk 30 is overwritten (process 5T6). Then, the new record is written to the position in the changed record pool 42 set in the pointer 46 of the new record control information 43a (processing 5
T7).

In this way, the application program can set the record data, specify the file name, the record number to be rewritten, and the new data to be written, and simply issue a record write command. It is possible to rewrite different records. Therefore, even when data is added in the middle of a file, there is no need to rewrite the entire file.

Next, when the application program issues a record read command of the sequential file 40, the CPU
The record reading operation performed under the control of 21 will be explained with reference to the flowchart of FIG. When reading a record, the application program specifies the file name, record number, and data input area of the memory 23 to which the read record is to be transferred, and issues a record read command.

When the CPU 21 decodes the record read command, the CPU 21 reads the designated record from the corresponding file on the magnetic disk 29 or floppy disk 30 via the disk controller 26, and stores it in the memory 24 (processing 5UI).

Next, the value of the no-change flag 44 of the control information 43a of the read record is determined and branched processing is performed 5U2), and if "0" is stored, it is read out on the memory 24 and stored in the data area 43b of the read record. Transfer all the data to the data input area of the memory 23 (processing 5U)
3).

On the other hand, if 1'' is stored in the no-change flag 44, the valid data of the data length stored in the valid data length 45 is read from the data area 43b of the control information 43a and sent to the data input area on the memory 23. Transfer (processing 5U4
). Also, “2” is set in the no-change flag 44 of the control information 43a.
If stored, the variable length record (change record) 43 is read from the position in the change record pool 42 indicated by the pointer 46 via the disk controller 26 and transferred to the memory 24 (processing 5U5). Then, the data written in the data area 43b of the record read onto the memory 24 is transferred to the data input area on the memory 23 (processing 5U6).

In this embodiment, the changed record pool is placed in the same sequential file, but it may be placed in a separate file.

Additionally, if the data length of the variable-length record to be rewritten increases, some data can be corrupted into the variable-length record group, and only the data that could not be written can be written to the changed record pool. The utilization efficiency of the storage space of external storage devices such as the above is improved.

When the present invention is incorporated into a computer that performs office processing in addition to an editor or a word processor, the productivity of the application program is improved because it becomes easier to create a program that processes a sequentially organized file with variable-length records.

〔Effect of the invention〕

As described in detail above, according to the present invention, records can be rewritten in a sequentially organized variable-length record file simply by an application program, etc. issuing a record write command. It is no longer necessary for the program to rewrite the entire program, and applications that process data in sequential files with variable-length records can
Improves program productivity.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram of the present invention. FIG. 2 is a block diagram of a system to which an embodiment of the present invention is applied. Figure 3(b) is a configuration diagram of a variable length record, and Figure 4 is:
FIG. 5 is a flowchart explaining the record rewriting operation of this embodiment. FIG. 6 is a system configuration diagram of a word processor using a conventional file management device. be. 1.' Record reading means, 2. Comparison means, 3. First creation means, 4. Second creation means. Patent applicant: Casio Computer Co., Ltd. Figure 1 (a) (b) Figure 3 Figure 4

Claims (1)

[Claims] In a file management device that forms a file on a storage medium and writes data to and reads data from the file, a variable length record containing control information and data stored on the storage medium is provided. From the sequential file composed of
record reading means for reading a variable length record for which a write request has been made; comparing means for comparing the record length of the current variable length record read from the record reading means and a new variable length record to be newly written; a first creation means for rewriting control information and data of the current variable length record on the storage medium when the comparison result is a predetermined result; and a first creation means for rewriting the control information and data of the current variable length record on the storage medium; If it is determined that the record length is long, the new variable-length record is written to a location on the storage medium that is different from the location where the current variable-length record is stored, and the new variable-length record is a second creation means for writing the writing position of the new variable length record into the control information of the file management device.