JPH04321976A - Digital data recording and reproducing 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]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital data recording and reproducing apparatus that handles data compression and restoration.

0002

[Background Art] In recent years, digital recording and playback technology has been applied to a wide range of fields, and in particular, remarkable progress has been made in the digital audio field, with rotary head type digital audio tape recorders (DAT) being put into practical use. It has come to be. On the other hand, attempts have been made to apply digital data recording and reproducing technology using a rotating head type tape such as DAT as a recording medium to auxiliary recording devices for computers. These computer auxiliary recording devices (hereinafter abbreviated as data DAT)
Instead of digitized audio data, digital data given from a computer is recorded sequentially in each data block, which is a predetermined amount of data format, and during playback, the digital data is It is read and output as a data block, making it possible to record, reproduce, and save extremely large amounts of data.

[0003] Regarding DAT, see Reference 1 ("Illustrated DAT
It is explained in detail in "Yomihon" (co-authored by Heitaro Nakajima and Kentaro Kodaka, published by Ohmsha).

A conventional data DAT is disclosed in, for example, Japanese Patent Laid-Open No. 1-245326. This is D
Commonly known as the ATA/DAT format.

[0005] Also, regarding this DATA/DAT,
Document 2 (“DAT application data storage device DATA/DAT
” co-authored by Keiji Noguchi, Takao Arai, and Toru Sanpei, JAS JOUR
NAL 1989 VOL. 29 NO. 12 Japan Audio Association) and Document 3 (“7th Draft PR
OPOSED AMERICAN NATIONAL
STANDARD HELICAL-SCAN DIG
ITAL COMPUTER TAPE CARTRI
DGE 3.81mm (0.150in) DATA/
DAT RECORDED FORMAT FOR I
NFORMATION INTERCHANGE” 1
November 1990).

[0006] Data compression is also a technology that has been widely used in recent years. This involves recording and reproducing data compressed on the host computer side using software on the OS or hardware on the data bus in an external storage device such as DATA/DAT. As for software, NIFTY-Serve for PC communication is free software.
"LHarc", "LH" (Creator:
In terms of hardware, the U.S. INF
"EXPANZ! (IC-105)" by OCHIP is well known. These provide an average compression ratio of 3:1.

[0007]

[Problems to be Solved by the Invention] However, in the above-mentioned conventional configuration, after data is compressed and recorded in a digital data recording/reproducing device, when reproducing the data, the data instructed by the host computer and the management information of the recorded data cannot be matched. There was a problem in that consistency could not be achieved and irregular data would be reproduced.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and an object thereof is to provide a digital data recording and reproducing apparatus that efficiently and reliably manages data when compressing and restoring data.

[0009]

[Means for Solving the Problems] In order to achieve this object, the digital data recording/reproducing apparatus of the present invention includes a data compression/decompression means, and a system area consisting of a data area and record information of the compressed data. A recording and reproducing means for recording and reproducing the included data blocks and search information of the data blocks, a calculation means for calculating the position of the read start position in the compressed data, the read capacity of the compressed data, and a data restoration algorithm. The data restoration algorithm selection means selects a data restoration algorithm.

0010

[Operation] With the above-described configuration, the present invention can easily convert the logical recording position and logical capacity into physical quantities on the tape from the compressed data and the record information that manages it. data can be restored.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a digital data recording/reproducing apparatus according to a first embodiment of the present invention. In FIG. 1, 1 is a cassette half, 2 is a reel,
3 is a tape, 4 is a cylinder, 5a and 5b are heads, 6 is a capstan that runs the tape 3, 7 is a mechanism control unit that controls the operations of the reel 2, cylinder 4, and capstan 6, and 8 is a recording operation. Then, the digital signal is encoded and a recording signal is supplied to the heads 5a and 5b.In the reproduction operation, a track synchronization signal is separated from the reproduction signal obtained from the heads 5a and 5b, and the track synchronization signal is transmitted to the mechanism control section 7. , a signal processing unit that decodes the reproduced signal and outputs a digital signal; 9 is a communication unit that sends and receives digital data and control information to and from an external device; 10 is a signal processing unit that temporarily transmits and receives digital data that the communication unit 9 sends and receives 11 is a data compression/decompression unit that compresses data in a recording operation and restores the compressed data in a playback operation; 12 is a data buffer that stores data in a data block; and the number of records as subdata to the signal processing section 8, and in the reproduction operation, extracts and outputs the leading record number and the number of records. 13 is a record information forming unit that forms record information in a data block, and 14 is a record information forming unit that forms record information in a data block; It is a main data recording and reproducing control unit that supplies main data consisting of an area and a system area to the signal processing unit 8, and extracts and outputs compressed data and record information in a reproducing operation. 15 is a read position calculation unit that calculates a read start position and read capacity on a data block based on the record information input from the main data recording and playback control unit 14;
This is a capacity calculation unit before data compression that calculates the capacity before compression of data to be read based on record information input from. Reference numeral 17 denotes a system control unit that inputs control information from the communication unit 9 and controls a series of recording and reproducing operations.

The operation of the digital data recording/reproducing apparatus of the first embodiment configured as described above includes a data recording operation and a reproducing operation, which will be explained in detail below.

First, the data recording operation will be explained. In FIG. 1, the system control unit 17, during recording operation,
The first record number in the data block and the number of records are given to the sub-data recording/playback control section 12, an operation command is given to the data buffer 10, the data is compressed by the data compression/decompression section 11, and the compressed data and records are The record information formed by the information forming section 13 is given to the main data recording/reproducing control section 14, and an operation command is given to the mechanism control section 7. The mechanism control unit 7 applies tension to the reel 2 according to the operation command, rotates the capstan 6 at a constant speed, and thereby drives the tape 3 at a constant speed.
Furthermore, the cylinder 4 is rotated at a constant speed. The signal processing section 8 processes the sub data given from the sub data recording/playback control section 12 and the main data given from the main data recording/playback control section 14, adds a track synchronization signal, and converts it into a track formation signal. By sequentially outputting to the heads 5a and 5b, diagonal tracks are continuously formed on the tape 3.

Next, the system control unit 17 also performs basic control regarding data reproduction operations. In Figure 1,
The system control section 17 gives operation commands to the mechanism control section 7. The signal processing section 8 extracts a track synchronization signal from the reproduced signals output from the heads 5a and 5b, and outputs it to the mechanism control section 7. The mechanism control unit 7 applies tension to the reel 2 and synchronizes the rotational speed of the capstan 6 and the rotational phase of the cylinder 4 based on the track synchronization signal, so that the heads 5a and 5b are configured on the tape 3. Make the track trace accurately. On the other hand, the signal processing unit 8 processes the reproduced signal and outputs sub data to the sub data recording/reproducing control unit 12 and main data to the main data recording/reproducing controller 14, respectively. The sub data recording/playback control unit 12 provides the first record number and the number of records in the data block that is the sub data to the system control unit 17, and the system control unit 17 receives the data calculated by the read position calculation unit 15. The data recorded on the tape 3 can be read out accurately by sequentially restoring the data in the data compression/restoration section 11 and having the communication section 9 start the transfer via the data buffer 10.

FIG. 2 shows the structure of tracks on the tape 3 formed by the above recording operation. In FIG. 2, one track A has a sub data recording area B and a track synchronization signal (Automatic Track Findi).
ng) Consists of a recording area C and a main data recording area D. Further, on the tape 3, as shown in E, an even number of tracks having the same structure as the track A are successively formed.

FIG. 3 shows the tape layout of the main data recording area of the data block formed by the above recording operation (Reference 3, "9.5 Data Layout of a
Group” (see page 49). A data block is composed of a data area that is a recording area for data input from an external device, and a system area that manages data in the data area, and the system area is composed of a record information list and data block information.

FIG. 4 shows the record information list formed by the above recording operation (Reference 3 "9.7 Record
ID List” (see page 54), and Figure 5
FIG. 2 is a configuration diagram of record information in the first embodiment.

In FIG. 5, record information includes record information identification information, capacity of record information, continuation information of previous and subsequent data blocks, capacity of data before compression, capacity of data after compression, and compression algorithm. It consists of the types of

FIG. 6 is a diagram showing the shape of a record when data of a variable length record is compressed. Next, a second embodiment of the present invention will be described using flowcharts shown in FIGS. 7 and 8.

First, "m" of the record in the data block
A case where reading of data from "th" to "n"th data is set will be explained using FIG. 7 (m≦n).

In step 100, "m" is added to the processing record number.
" is set. In step 101, the start position of the processing record number is calculated, and in step 102, the reading section is set from the data capacity after compression.Next, step 103
In step 104, a data restoration algorithm is set from the data compression algorithm information in the record information.
The data compression/decompression unit 11 decompresses the data and stores it in the data buffer 10.
Send to. Next, in step 105, if the processing record number is "n", the process ends; if it is not "n", the process proceeds to step 106, where the process record number is incremented by one, and the process proceeds to step 101.

Next, "m" of the record in the data block
A case in which confirmation of the capacity of data from "th" to "n" is set will be described using FIG. 8 (m≦n).

In step 200, "m" is added to the processing record number.
” and set check capacity 1 to “0” in step 201.
In step 202, check capacity 2 is set to "0". In step 203, the capacity of the data before compression is added to check capacity 1, in step 204, the capacity of data after compression is added to check capacity 2, and in step 205, if the processing record number is "n", the process ends. ,”n”
If not, the process proceeds to step 206, increments the processing record number by one, and proceeds to step 203.

Next, a third embodiment of the present invention will be explained using the block diagram of a digital data recording/reproducing apparatus shown in FIG.

In FIG. 9, 1 is a cassette half, 2 is a reel, 3 is a tape, 4 is a cylinder, 5a and 5b are heads, 6 is a capstan for running the tape 3, and 7 is a reel 2, a cylinder 4, and a capstan. 6 is a mechanism control unit that controls the operation of 6, and 8 encodes a digital signal in the recording operation and supplies the recording signal to the heads 5a and 5b;
In the reproduction operation, a signal processing section 9 separates a track synchronization signal from the reproduction signal obtained from the heads 5a and 5b, transmits the track synchronization signal to the mechanism control section 7, decodes the reproduction signal, and outputs a digital signal. A communication unit that transmits and receives digital data and control information to and from an external device; 10 is a data buffer that temporarily stores the digital data transmitted and received by the communication unit 9; 11 is a data buffer that compresses data during recording operation and performs playback. In operation, 12 is a data compression/decompression unit that restores compressed data, and in recording operation, it supplies the first record number in the data block and the number of records as subdata to the signal processing unit 8, and reproduces the data. In operation, it is a sub-data recording and reproducing control unit that extracts and outputs the leading record number and the number of records. 13 is a record information forming unit that forms record information in a data block, and 14 is a record information forming unit that forms record information in a data block; It is a main data recording and reproducing control unit that supplies main data consisting of an area and a system area to the signal processing unit 8, and extracts and outputs compressed data and record information in a reproducing operation. 15 is a main data recording/reproducing control section 1
16 is a read position calculation unit that calculates the read start position and read capacity on the data block based on the record information input from 4, and 16 is a read position calculation unit that calculates the read start position and read capacity on the data block based on the record information input from This is a capacity calculation unit before data compression that calculates the capacity before compression of data to be compressed. 18 is a recording operation, and is a logical record fixed capacity setting unit that sets the fixed capacity of the record sent to the communication unit 9 in the main data recording/playback control unit 14; 17 is a logical record fixed capacity setting unit that inputs control information from the communication unit 9 and performs a series of This is a system control unit that controls recording and reproducing operations.

The operation of the digital data recording/reproducing apparatus of the third embodiment configured as described above includes a data recording operation and a reproducing operation, which will be explained in detail below.

First, the data recording operation will be explained. In FIG. 9, the system control unit 17, during recording operation,
The first record number in the data block and the number of records are given to the sub-data recording/playback control section 12, an operation command is given to the data buffer 10, the data is compressed by the data compression/decompression section 11, and the compressed data and records are The record information formed by the information forming section 13 and the logical record fixed capacity set by the logical record fixed capacity setting section 18 are given to the main data recording/reproducing control section 14, and an operation command is given to the mechanism control section 7.

The mechanism control section 7 applies tension to the reel 2 in accordance with the operation command, rotates the capstan 6 at a constant speed to drive the tape 3 at a constant speed, and further rotates the cylinder 4 at a constant speed. The signal processing section 8 processes the sub data given from the sub data recording/playback control section 12 and the main data given from the main data recording/playback control section 14, adds a track synchronization signal, converts it into a track formation signal, and outputs the signal to the head. By sequentially outputting the signals to 5a and 5b, diagonal tracks are continuously formed on the tape 3.

Next, the system control unit 17 also performs basic control regarding data reproduction operations. In FIG. 9,
The system control section 17 gives operation commands to the mechanism control section 7. The signal processing section 8 extracts a track synchronization signal from the reproduced signals output from the heads 5a and 5b, and outputs it to the mechanism control section 7. The mechanism control unit 7 applies tension to the reel 2 and synchronizes the rotational speed of the capstan 6 and the rotational phase of the cylinder 4 based on the track synchronization signal, so that the heads 5a and 5b are configured on the tape 3. Make the track trace accurately. On the other hand, the signal processing unit 8 processes the reproduced signal and outputs sub data to the sub data recording/reproducing control unit 12 and main data to the main data recording/reproducing controller 14, respectively.

The sub-data recording/playback control section 12 provides the first record number and the number of records in the data block, which is the sub-data, to the system control section 17, and the system control section 17 calculates the number of records from the read-out position calculation section 15. The data recorded on the tape 3 can be read out accurately by sequentially restoring the data in the data compression/restoration section 11 and starting the transfer to the communication section 9 via the data buffer 10. . FIG. 10 is a configuration diagram of record information in the third embodiment. In FIG. 10,
The record information is composed of record information identification information, the capacity of the record information, continuation information of previous and subsequent data blocks, the capacity of data after compression, and the type of compression algorithm.

Further, the logical record fixed capacity is recorded in the data block information shown in FIG.

FIG. 11 is a diagram showing the shape of a record that is made variable length after compression when fixed length record data is compressed.

Next, a fourth embodiment of the present invention will be explained using the flowchart shown in FIG.

First, "m" of the record in the data block
The case where reading of the "n"th data is set is the same as in the second embodiment described using FIG. 7 (m≦n).

Next, "m" of the record in the data block
A case in which confirmation of the capacity of data from "th" to "n" is set will be described using FIG. 12 (m≦n).

In step 300, "m" is added to the processing record number.
", and in step 301 set check capacity 1 to the value obtained by multiplying the fixed logical record capacity by the number of records. In step 302, set check capacity 2 to "0". In step 303, The capacity is added to the check capacity 2, and in step 304 the processing record number is
If it is "n", the process ends; if it is not "n", the process proceeds to step 305, increments the processing record number by one, and proceeds to step 302.

Next, a fifth embodiment of the present invention will be explained using the block diagram of a digital data recording/reproducing apparatus shown in FIG.

In FIG. 13, 1 is a cassette half; 2 is a cassette half;
3 is a reel, 3 is a tape, 4 is a cylinder, 5a and 5b are heads, 6 is a capstan for running the tape 3, 7 is a mechanism control unit that controls the operations of the reel 2, cylinder 4, and capstan 6; In the recording operation, encodes the digital signal and supplies the recording signal to the heads 5a and 5b,
In the playback operation, the track synchronization signal is separated from the playback signals obtained from the heads 5a and 5b, and the track synchronization signal is transmitted to the mechanism control unit 7, and the signal processing unit decodes the playback signal and outputs a digital signal. 1 is a communication unit that transmits and receives digital data and control information to and from an external device; 10 is a data buffer that temporarily stores digital data transmitted and received by the communication unit 9; 11 is a data buffer that compresses data during recording operation; In the playback operation, it is a data compression/decompression unit that restores compressed data, and 1
Reference numeral 2 denotes a sub-sub which supplies the first record number and the number of records in the data block as sub data to the signal processing unit 8 in the recording operation, and extracts and outputs the first record number and the number of records in the reproduction operation. This is a data recording/reproduction control section. 13 is a record information forming unit that forms record information in a data block, and 14 is a record information forming unit that forms record information in a data block; It is a main data recording and reproducing control unit that supplies main data consisting of an area and a system area to the signal processing unit 8, and extracts and outputs compressed data and record information in a reproducing operation. 15 is a read position calculation unit that calculates a read start position and read capacity on a data block based on the record information input from the main data recording and playback control unit 14; This is a capacity calculation unit before data compression that calculates the capacity before compression of read data based on input record information. 18 is a recording operation, in which the fixed capacity of the record sent to the communication section 9 is transferred to the main data recording/playback control section 1.
This is a logical record fixed capacity setting section to be set to 4, and 19
17 is a physical record fixed capacity setting unit that sets the fixed capacity of records in the data area in the main data recording/playback control unit 14 for recording operations, and 17 inputs control information from the communication unit 9 to control a series of recording/playback operations. This is the system control unit.

The operation of the digital data recording/reproducing apparatus of the fifth embodiment constructed as described above includes a data recording operation and a reproducing operation, which will be explained in detail below.

First, the data recording operation will be explained. In FIG. 13, during the recording operation, the system control unit 17 provides the first record number and the number of records in the data block to the sub-data recording/playback control unit 12, and gives an operation command to the data buffer 10 to compress the data. - Compressed data compressed by the restoration unit 11, record information formed by the record information forming unit 13, logical record fixed capacity set by the logical record fixed capacity setting unit 18, and physical record fixed capacity setting unit 19 The physical record fixed capacity set in step 1 is given to the main data recording/reproducing control section 14, and an operation command is given to the mechanism control section 7. The mechanism control unit 7 applies tension to the reel 2 according to the operation command, rotates the capstan 6 at a constant speed to drive the tape 3 at a constant speed, and further drives the tape 3 at a constant speed.
rotate at a constant speed. The signal processing section 8 processes the sub data given from the sub data recording/playback control section 12 and the main data given from the main data recording/playback control section 14, adds a track synchronization signal, and converts it into a track formation signal. By sequentially outputting to the heads 5a and 5b, diagonal tracks are continuously formed on the tape 3.

Next, the system control unit 17 also performs basic control regarding the data reproduction operation. In FIG. 13, the system control section 17 gives an operation command to the mechanism control section 7. The signal processing section 8 extracts a track synchronization signal from the reproduced signals output from the heads 5a and 5b, and outputs it to the mechanism control section 7. The mechanism control unit 7 applies tension to the reel 2 and synchronizes the rotational speed of the capstan 6 and the rotational phase of the cylinder 4 based on the track synchronization signal, so that the heads 5a and 5b are configured on the tape 3. Make the track trace accurately. On the other hand, the signal processing unit 8 processes the reproduced signal and outputs sub data to the sub data recording/reproducing control unit 12 and main data to the main data recording/reproducing controller 14, respectively. The sub data recording/playback control unit 12 provides the first record number and the number of records in the data block that is the sub data to the system control unit 17, and the system control unit 17 receives the data calculated by the read position calculation unit 15. The data recorded on the tape 3 can be read out accurately by sequentially restoring the data in the data compression/restoration section 11 and having the communication section 9 start the transfer via the data buffer 10.

FIG. 14 is a diagram showing the structure of record information in the fifth embodiment. In FIG. 14, the record information is composed of record information identification information, the capacity of the record information, continuation information of the previous and subsequent data blocks, related information of the previous and subsequent record information, and the type of compression algorithm.

Further, the logical record fixed capacity and the physical record fixed capacity are recorded in the data block information shown in FIG. 3.

FIG. 15 is a diagram showing the shape of a record made into a fixed length after compression when data of a fixed length record is compressed. FIG. 16 shows the content of the related information of the previous and subsequent record information, and shows whether or not the record continues immediately before and after. Bit allocation is arbitrary.

Next, a sixth embodiment of the present invention will be described using flowcharts shown in FIGS. 17 and 18.

[0047] Here, the logical record number is a record number based on the fixed capacity of records set from an external device, and the processing record number is a record number based on the fixed capacity of records recorded in the data area. .

First, the case where reading of data from "m" to "n" of logical records in a data block is set will be explained using FIG. 17 (m≦n).
.

At step 400, the logical record number is set to "0".
", and in step 401 the processing record number is set to "0".
Next, in step 402, the processing record number is incremented by one, and the process proceeds to step 403. If the record is discontinuous with the record immediately after, the process proceeds to step 404, and if it is continuous, the process proceeds to step 402 again.Step 404 Then, the logical record number is incremented by one, and the process proceeds to step 405. If the logical record number is "m", the process proceeds to step 406; if not, the process proceeds to step 402 again.Next, in step 406, the process proceeds to step 402. Set the read interval of the processed record, set the restoration algorithm in step 407,
In step 408, the compressed data is restored using the set restoration algorithm. Next, the process proceeds to step 409, and if the immediately following record is discontinued, the process proceeds to step 410, and if the record continues, the process proceeds to step 411, where the processing record number is incremented by one, and the process proceeds to step 406 again. In step 410, if the logical record number is "n", the process ends; if not, the logical record number is incremented by one, and the process returns to step 411.

Next, a case where confirmation of the capacity of data from the "n"th to "m"th logical records in the data block is set will be explained using the flowchart of FIG. 18 (m≦n).

At step 500, the logical record number is set to "0".
", and in step 501 the processing record number is set to "0".
Next, in step 502, the processing record number is incremented by one, and the process proceeds to step 503. If the record is discontinuous with the record immediately after, the process proceeds to step 504, and if it is continuous, the process proceeds to step 502 again.Step 504 Then, the logical record number is incremented by one, and the process proceeds to step 505. If the logical record number is "m", the process proceeds to step 506; if not, the process proceeds to step 502 again.In step 506, the processing record number is is set as the first processing record number, and the process proceeds to step 507.Next, step 507
Then, if there is no continuation to the immediately following record, step 508
If the process continues, the process proceeds to step 509, increments the processing record number by one, and proceeds to step 507 again. In step 508, if the logical record number is "n", the process proceeds to step 511; if not, step 510
The process proceeds to step 509, increments the logical record number by one, and proceeds to step 509 again. In step 511, check capacity 1 is set to a value obtained by multiplying the logical record fixed capacity by the number of logical records, and the process proceeds to step 512, where check capacity 2 is set to a value obtained by multiplying the record fixed capacity by the number of processing records, Finish the process.

Note that the mechanism control section 7, the sub data recording and playback control section 12, the record information forming section 13, the main data recording and playback control section 14, the read position calculation section 15, the capacity calculation section 16 before data compression, and the system control section 17. Although the logical record fixed capacity setting section 18 and the physical record fixed capacity setting section 19 are respectively independent control sections, several of these may be integrated and configured by a microcomputer and realized as software. Further, although the minimum unit of recording is a record, it may be a file that is a collection of one or more records. Furthermore, the data compression/restoration algorithm may include a non-compression algorithm.

[0053]

[Effects of the Invention] As described above, according to the present invention, a compression/decompression algorithm can be selected for each record, and records can be easily managed without distinguishing between fixed-capacity and variable-capacity records set from the outside. It has wonderful features such as low storage capacity.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a digital data recording/reproducing device in first and second embodiments of the present invention.

[Figure 2]
Pattern diagram showing the configuration of the tape format

[Figure 3] Tape layout diagram of the main data recording area of the data block

[Figure 4] Configuration diagram of record information list in the first embodiment

[Figure 5] Configuration diagram of record information in the first and second embodiments

[Figure 6] Record shape diagram during data compression of variable length records in the first and second embodiments

FIG. 7 is a flowchart explaining the procedure for reading data in the second embodiment.

FIG. 8 is a flowchart explaining the procedure for checking data in the second embodiment.

FIG. 9 is a block diagram showing the configuration of a digital data recording/reproducing device in third and fourth embodiments of the present invention.

[Figure 10
] Configuration diagram of record information in the third and fourth embodiments

[Fig. 11] Diagram of the shape of records made variable length after compression when fixed-length record data is compressed in the third and fourth embodiments.

FIG. 12 is a flowchart explaining the procedure for checking data in the fourth embodiment of the present invention.

FIG. 13 is a block diagram showing the configuration of a digital data recording/reproducing device in fifth and sixth embodiments of the present invention.

[Figure 1
4] Configuration diagram of record information in the fifth and sixth embodiments

[Fig. 15] A diagram of the shape of the record after compression when the fixed-length record data is compressed in the fifth and sixth embodiments.

FIG. 16 is an explanatory diagram showing the content of related information of previous and subsequent record information in the fifth and sixth embodiments.

FIG. 17 is a flowchart explaining the procedure for reading data in the sixth embodiment.

FIG. 18 is a flowchart explaining the procedure for checking data in the sixth embodiment.

[Explanation of symbols]

1 Cassette half 2 Reel 3 Tape 4 Cylinder 5a, 5b head 6 Capstan 7 Mechanism control section 8 Signal processing section 9 Communication Department 10 Data buffer 11 Data compression/restoration section 12 Sub data recording and playback control section 13 Record information formation section 14 Main data recording and playback control section 15 Readout position calculation unit 16 Capacity calculation section before data compression 17 System control section 18. Logical record fixed capacity setting section 19 Physical record fixed capacity setting section

Claims (9)

[Claims] 1. Communication means for transmitting and receiving digital data and control information from an external device; and data compression/restoration means having one or more data compression/restoration algorithms for compressing the data upon reception and restoring it upon transmission. , a set of frames consisting of a plus azimuth track and a minus azimuth track, a data area consisting of data obtained from the data compression/reconstruction means, data information for transmitting and receiving the data to and from the communication means, and the data compression and decompression means. - a first recording means for forming a data block on the tape including a system area consisting of information of data compressed or uncompressed by the decompression means; A second recording means for recording in a specific area, a first reproducing means for reproducing the data block recorded by the first recording means, and search information recorded by the second recording means are set in advance. a second reproducing means for reproducing the positive azimuth track and the negative azimuth track continuously or intermittently at the speed of the digital data recording/reproducing device. 2. The digital data recording and reproducing apparatus according to claim 1, wherein the data compression/decompression algorithm includes a non-compression algorithm. [Claim 3] Corresponding to a record, which is the minimum unit of recording, record information identification information, record information capacity, continuation information of previous and subsequent data blocks, data capacity before compression, and after compression. Record information consisting of data capacity and compression algorithm type;
2. The digital data recording and reproducing apparatus according to claim 1, wherein the recording means arranges all the records recorded in the data block in a preset order and records them in the system area. 4. Corresponding to the record, which is the minimum unit of recording, record information identification information, the capacity of the record information, continuation information of the previous and subsequent data blocks, the capacity of the data after compression, and the compression algorithm. The first recording means is record information consisting of a type, an arrangement of an order set in advance for all records recorded in a data block, and data information set by the communication means. 2. The digital data recording and reproducing apparatus according to claim 1, wherein a fixed record capacity for all records in a certain data block is recorded in a system area. [Claim 5] Corresponding to a record, which is the minimum unit of recording, record information identification information, record information capacity, continuation information between previous and subsequent data blocks, related information between previous and subsequent record information, and compression. Record information consisting of the type of algorithm, the first recording means is:
A preset order arrangement for all records recorded in a data block, a logical record capacity which is data information set by the communication means, and a preset fixed order for all records in the data block. 2. The digital data recording and reproducing apparatus according to claim 1, wherein the record capacity of the digital data is recorded in the system area. 6. A first detecting means for detecting record information corresponding to a record to be read from an arrangement of record information recorded in a system area based on a read start record number which is a control signal received from the communication means; a first calculation means for calculating the position of the read start position in the compressed data from the compressed capacity of all record information up to the read start record; and a first calculation means for calculating the position of the read start position in the compressed data, and from the number of records to be read which is a control signal received from the communication means. , a second calculation means for calculating the read capacity of the compressed data from the compressed capacity of all the record information of the record to be read from the start of reading; and information obtained by the first calculation means and the second calculation means. a third calculation means for calculating read position information on the tape from the start of reading, and a fourth calculation means for calculating the read capacity of restored data from the uncompressed capacity of all record information of records read from the start of reading; 4. The digital data recording and reproducing apparatus according to claim 3, further comprising data restoration algorithm selection means for selecting a data restoration algorithm corresponding to a data compression/restoration algorithm of record information. 7. A first detecting means for detecting record information corresponding to a record to be read from an arrangement of record information recorded in a system area based on a read start record number which is a control signal received from the communication means; a first calculation means for calculating the position of the read start position in the compressed data from the compressed capacity of all the record information up to the read start record; and from the number of read records which is a control signal received from the communication means. , a second calculation means for calculating the read capacity of the compressed data from the compressed capacity of all the record information of the record to be read from the start of reading; and information obtained by the first calculation means and the second calculation means. a third calculation means that calculates read position information on the tape from the read position information; a fifth calculation means that calculates the read capacity of the restored data from the total number of records up to the read start record and the fixed record capacity; 5. The digital data recording and reproducing apparatus according to claim 4, further comprising data restoration algorithm selection means for selecting a data restoration algorithm corresponding to a data compression/restoration algorithm of record information. 8. A first method for detecting record information corresponding to the record to be read from the arrangement of record information recorded in the system area and previous and subsequent record information from the read start record number which is a control signal received from the communication means. a sixth calculation means for calculating a position in the compressed data of a read start position from the total number of records up to the read start record and a fixed record capacity; and a control received from the communication means. seventh calculating means for calculating the read capacity of compressed data from the number of read records which is a signal, the total number of records to be read from the start of reading and the fixed record capacity; the sixth calculating means; an eighth calculating means for calculating read position information on the tape from information obtained by the seventh calculating means;
a ninth calculation means for calculating the read capacity of the restored data from the total number of records up to the read start record and the fixed record capacity; and a ninth calculation means corresponding to the data compression/restoration algorithm of the record information. 6. The digital data recording and reproducing apparatus according to claim 5, further comprising: data restoration algorithm selection means for selecting a data restoration algorithm. Claim 9: Claims 1, 3, 4, 5, and 6, wherein the minimum unit of recording is a file that is a collection of one or more records.
, 7 or 8.