JPH04289561A - Method and device for recording record of variable length format - Google Patents

Abstract

PURPOSE:To effectively use the data area and to efficiently perform retrieval in a short time by recording a first bit pattern in the head of the IC part of a sector and recording a second bit pattern in the head of each of the other parts. CONSTITUTION:A record having a variable length format is received and is formatted in a sector of a record having a fixed length format. In this case, the first bit pattern is added to the head of an ID part 23 of a sector 22 of the record having the fixed length format where a count part 21 as the field, where format control information of the record having the variable length format is held, should be recorded, and it is recorded. The second bit pattern is added to the heads of ID parts and data areas where the other count parts 21, key parts 31, and data parts 41 should be recorded, and they are recorded. Thus, all data parts are used as the data area, and the count part is efficiently retrieved in a short time.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for recording variable-length records, and more particularly to a method and apparatus for recording variable-length records using fixed-length records.

0002

2. Description of the Related Art Conventional variable-length format record recording methods and devices use identification codes for each sector to distinguish each sector when using, for example, a magnetic disk with a fixed-length format as a recording medium. Section (hereinafter referred to as I
However, in the conventional format, it was not possible to distinguish the type of data recorded in the data area using the ID section. Therefore, when emulating variable length format on a fixed length format magnetic disk device,
Write data by adding a header to the beginning of the data area of each sector to determine whether the data recorded in this sector is in the count part, key part, or data part of a variable-length record. method was used.

0003

[Problems to be Solved by the Invention] The above-described conventional variable length format record recording method and apparatus have a problem in that when emulating a variable length format in a fixed length format magnetic disk device, etc., the beginning of the data area of each sector is The method used was to write data by adding a header to determine whether the data recorded in this sector was in the count part, key part, or data part of a variable-length record. There is a problem in that the entire data portion of a sector cannot be used as a data area. In addition, unless the data part of a sector is read, it is impossible to determine whether this data is a count part, key part, or data part, so this is a field that holds format control information of a variable-length format record. In the operation of searching for the sector in which the count part is recorded, it is necessary to read out the sectors one after another and make a decision.
There is not enough processing time, and since a header is added to the beginning of each sector to indicate the attributes of the data recorded in this sector, it is necessary to process the header when writing or reading data. There are various constraints on execution, such as the complexity of data transfer processing, and there are problems in that it is difficult to realize an efficient recording method.

An object of the present invention is to use the entire data portion of each sector as a data area in order to effectively utilize the data area, so that when writing data in a variable length format record, it can be written as it is, and when it is read, it can be transmitted as is. An object of the present invention is to provide an efficient method and apparatus for recording records in a variable length format, in which searching for the count part of a corresponding record is shortened and simple.

[0005]

Means for Solving the Problems The present invention provides a variable length format record recording method for receiving a variable length format record and formatting it into a fixed length record sector. In the sector of the fixed-length format record that records the count section, which is a field that holds format control information of the variable-length format record, a first bit pattern is added to the beginning of the synchronization byte of the identification code section of this sector. and a second bit pattern is added to the head of the synchronization byte of the data in the count section, the identification code section of each of the key section and data section of the record in the variable length format, and the recording data. .

[0006] In the variable length format record recording method of the present invention, the bit pattern at the head of the synchronization byte detected when reading the recorded content may be identified, and the already recorded variable length format record may be reproduced.

[0007] The variable length format record recording device of the present invention has a first memory which holds a selection signal input from the outside for selecting a bit pattern to be added to the synchronization byte of the identification code portion of the sector of the fixed length format record. 1
a register, second and third registers that are inputted in advance and hold two bit patterns of the synchronization byte, and holding of the second and third registers that receive a selection signal held by the first register. 2 of the sync bytes to
a selector that selects and outputs one of the two bit patterns; a fourth register that holds the bit pattern output by this selector; a data writing unit that writes data to a storage medium that stores fixed-length format records by combining the bit patterns output from the registers; and a data read unit that reads data from the storage medium that stores fixed-length format records. and a synchronous byte detection section that detects and outputs the synthesized bit pattern from the data read by the data reading section.

[0008]

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

FIG. 1 is a block diagram of an embodiment of the present invention in which a magnetic disk is used as a storage medium.

The variable length format record recording device 1 of the present invention receives a selection signal 11 input from the outside in order to select a bit pattern to be added to the synchronization byte of the identification code section of the sector of the fixed length format record. A flip-flop (hereinafter referred to as F/F) 2 that holds, registers 3 and 4 that hold the two bit patterns of the synchronization byte input in advance, and registers 3 and 4 that receive the selection signal held by F/F2. A selector 5 that selects and outputs one of the two bit patterns of the synchronization byte to be held.
, a write synchronization byte holding register 6 that holds the bit pattern output from the selector 5, a write gate signal 12 and write data 13 of a variable-length format record input from the outside, and a write synchronization byte holding register 6.
a data writing unit 8 that synthesizes bit patterns output from the magnetic disk medium 7 and writes a record in a fixed length format to a magnetic disk medium 7, and reads data 15 from the magnetic disk medium 7 according to a read request of a read gate signal 14. The synchronization byte detection section 10 detects a bit pattern synthesized from the read data 15 read by the data reading section 9 and outputs it as pattern signals 16 and 17.

Note that, if the detected bit pattern is a bit pattern held in the register 3, the synchronous byte detection unit 10 outputs only the pattern signal 16, and outputs only the pattern signal 16 to the register 4.
If the bit pattern is held by the pattern signal 16,
Outputs 17.

Next, the operation will be explained.

The variable length format record recording device 1 is controlled by a processing device (not shown), and when the F/F 2 is held at “0” by the selection signal 11, the selector 5 is controlled by the register 3. When the bit pattern of the synchronous byte "19H"("XXH" indicates hexadecimal display) is selected and output, and F/F2 is held at "1", selector 5 indicates the value held by register 4. "1EH", which is the bit pattern of the synchronization byte, is selected and output. Here, when F/F2 is held at "0" and the write gate signal 12 is activated, the data writing section 8 adds "19H" as a synchronization byte to the beginning of the write data 13 and magnetically Write to disk medium 7, and similarly write to F/F2
When the write gate signal 12 is activated by keeping it at "1", "1E
H" is added and written on the magnetic disk medium 7.

At the time of reading, the data reading section 9 reads the read data 15 from the magnetic disk medium 7 in accordance with the read request of the read gate signal 14. At this time, the synchronous byte detector 1
0 detects the synchronization byte of read data 15 and outputs “19H”.
” is detected, only pattern signal 16 is output, and “1E
If H'' is detected, pattern signals 16 and 17 are output.

Next, a description will be given of the operation when a variable length format record is recorded in a fixed length format sector.

FIG. 2 is an explanatory diagram for explaining a method of dividing and recording a variable-length format record into fixed-length format sectors. The description will be made according to FIG. 2, but the names and symbols of the functions will be those shown in FIG. 1.

Count section 2 is a field that holds format control information for records in variable length format.
In the fixed length format sector 22 in which 1 is recorded, the processing device holds F/F2 at "1" by the selection signal 11, so that the selector 5 selects "1EH" which is the bit pattern of the synchronization byte held in the register 4. ” is selected and output, the data writing unit 8 writes “
1EH” is added and the ID section 23 is written. Next, the F/F
2 is held at “0”, so that the selector 5 selects “1”, which is the bit pattern of the synchronization byte held in register 3.
9H" is selected and output, the data writing section 8 writes "19H" at the beginning of the data area 24 of the sector 22, and the data of the count section 21 and the subsequent key section 31 and data section are written in the data area 24. 41 is stored.Next, when recording the key part 31, by holding F/F2 at "0", the data writing part 8 writes the data to the sector 32. "19H" is added to the beginning of the ID field 33, and then "19H" is written to the beginning of the data area 34, and the key part data is written to the data area 34.Similarly, the data field 41
When recording “19H” at the beginning of sectors 42 and 52,
” is added to the ID sections 43 and 53, and then "19H" is written at the beginning of the data areas 44 and 54, and the data section data is written to the data areas 44 and 54. Note that at the end of each data area is an error correction code (CRC)
) is added. Furthermore, at the end of the data section data, an end-of-field code (hereinafter referred to as EOF) indicating the end is recorded.

Next, when reading a record in variable length format recorded in such a format, the I of the read sector is
If the synchronization byte of the D section is "19H", the synchronization byte detection section 10 outputs only the pattern signal 16 and does not output the pattern signal 17. 21 is not recorded, the operation starts to read the ID section of the next sector, and if the synchronization byte of the ID section of the read sector is "1EH", pattern signal 17 is output, so this The processing device that received this notice knows that the count section 21 is recorded in this sector, and subsequently reads out the count section data in the data area 24 of this sector. Part 4
Other recorded records of 1 can be written and read.

In this embodiment, the type of synchronization byte is “
Although two types of synchronization bytes, ``1EH'' and ``19H'', are used, it is also possible to use bit patterns other than those described above as types of synchronization bytes.

[0020]

As explained above, the present invention provides a first bit pattern that holds an externally input selection signal in order to select a bit pattern to be added to the synchronization byte of the sector identification code portion of a fixed-length record. 1 register, second and third registers that are inputted in advance and hold two bit patterns of the synchronization byte, and the second and third registers that receive the selection signal held by the first register and hold the synchronization byte. A selector that selects and outputs one of the two bit patterns of a byte, a fourth register that holds the bit pattern output by this selector, and a fourth register that holds the write data of a variable-length record that is input from the outside. a data writing unit that combines the bit patterns output from registers No. 4 and writes the data to a storage medium that stores fixed-length format records, and data that reads data from the storage medium that stores fixed-length format records. By providing a readout section and a synchronous byte detection section that detects and outputs a bit pattern synthesized from the data read by the data readout section, the entire data section of each sector can be used as a data area for effective use of the data area. use,
When writing data in a variable-length format record, it can be written as it is, and when reading it, it can be transmitted as is, and the processing time for searching the count section of the corresponding record is shortened, simple, and efficient.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention using a magnetic disk as a storage medium.

FIG. 2 is an explanatory diagram for explaining a method of dividing and recording a variable-length format record into fixed-length format sectors.

[Explanation of symbols]

1 Recording device for variable length format records 2
Flip-flop (F/F) 3, 4 Register 5 Selector 6 Write synchronization byte holding register 7 Magnetic disk medium 8 Data writing section 9 Data reading section 10 Synchronization byte detection section 11 Selection signal 12 Write gate signal 13 Write data 14 Read gate signal 15 Read data 16, 17 Pattern signal

Claims (3)

[Claims] 1. A variable length format record recording method for receiving a variable length format record and formatting it into a fixed length record sector, comprising: a count section which is a field holding format control information of the variable length format record; In the sector of the fixed-length format record that records the data, a first bit pattern is added to the beginning of the synchronization byte of the identification code section of this sector, and the data of the count section and the key of the variable-length format record are recorded. A method for recording a record in a variable length format, characterized in that a second bit pattern is added to the beginning of an identification code part of each part and data part and a synchronization byte of record data. 2. The variable length format record according to claim 1, wherein the first bit pattern of the synchronization byte detected when reading the recorded content is identified, and the recorded variable length format record is reproduced. Recording method. 3. A first register that holds a selection signal input from the outside to select a bit pattern to be added to a synchronization byte of an identification code portion of a sector of a record in a fixed length format; second and third registers that hold a bit pattern input in advance, and the second and third registers that receive a selection signal held by the first register and hold the synchronization byte. A selector that selects and outputs one of them, a fourth register that holds the bit pattern output by this selector, and a variable-length record write data input from the outside and the output of the fourth register. a data writing unit that writes data into a storage medium that stores fixed-length records by combining bit patterns; a data reading unit that reads data from the storage medium that stores fixed-length records; A variable length format record recording device comprising: a synchronous byte detection unit that detects and outputs the synthesized bit pattern from the data read by the data reading unit.