JP2932398B2 - Access device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to an access device for quickly accessing the end of a data area, which is a seam of recording, when a new data area is formed.

(Prior art) In recent years, digital recording / reproducing technology has been applied to a wide range of fields. In particular, the digital audio field has made remarkable progress, and a rotary head digital audio tape recorder (DAT) and the like have been put into practical use. Has been reached. On the other hand, attempts have been made to apply digital data recording / reproducing technology using a rotary head type tape such as DAT as a recording medium to an auxiliary recording device of a computer. These computer auxiliary recording devices (hereinafter, abbreviated as data DAT) sequentially record digital data given from the computer in place of digitized audio data in data blocks each having a predetermined fixed data format. At the time of reproducing operation, digital data is read and output as a data block as in the case of audio application, and recording, reproducing, and storing extremely large-capacity data are enabled.

The DAT is described in detail in Reference 1 (“Illustrated DAT Reader” by Heitaro Nakajima and Kentaro Odaka Ohmsha).

As data DAT formats, two formats, DATA / DAT and DDS, are generally known.

Regarding DATA / DAT, see Reference 2 ("DAT application data storage device DATA / DAT") Keiji Noguchi, Takao Arai, Toru Sampei
JAS JOURNAL 1989 VOL.29 No.12 Japan Audio Association) and Reference 3 (“5th Draft PROPOSED AMERICAN NATION”
AL STANDARD HELICAL−SCAN DIGITAL COMPUTER TAPE CA
RTRIDGE 3.81mm (0.150in) DATA / DAT RECORD FORMAT FO
R INFORMATION INTERCHANGE, "May 30, 1990).

For DDS, refer to Reference 4 (“DAT applied data recording format DDS” Kentaro Odaka JAS JOURNAL 1
989 VOL.29 No.12 Japan Audio Association) and Reference 5
("7th Draft PROPOSED AMERICAN NATIONAL STANDARD
HELICAL-SCAN DIGITAL COMPUTER TAPE CARTRIDGE 3.81
mm (0.150in) DIGITAL DATA STRAGE (DDS) RECORD FORM
AT FOR INFORMATION INTERCHANGE ”9th April 1990).

In addition, in the search for the end of data, in a typical 1/4 inch (2.54 / 4 cm) cartridge (hereinafter abbreviated as QIC) of a conventional data backup device, a file mark block following an erase area of 45 inches or less is used. There is a device for searching at high speed by reproducing the optional control block.

For QIC, refer to Reference 6 (“QIC-24 REVISION D PROP
OSED STANDARD FOR DATA INTERCHANGE ON THE STREAMIN
G 1/4 INCH MAGNETICTAPE CARTRIDGE USING GROUP RECO
RDING AT 10,000 FRPIAPRIL 22,1983).

(Problems to be Solved by the Invention) However, in the above conventional configuration, the access speed at the end of data in the QIC is as low as 1 to 2 times the normal reproduction speed, whereas the data DAT is as high as 200 to 400 times as fast. Therefore, the first problem is that the area indicating the end of the data is skipped and time is spent searching, and when the tape format is repeated, the end information of the old and new data is mixed, and an incorrect position is incorrectly detected. The second problem of searching as the end of data, and the speed control can be performed because the position of the target cannot be predicted before passing the target when rewinding and fast-forwarding after the end of data is detected and stopped. However, there is a third problem that much time is spent for that purpose.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and has as its object to provide an access device that realizes efficient end-of-data search.

(Means for Solving the Problems) An access device according to the present invention comprises: a recording / reproducing means for recording / reproducing user data and an area identification number or a format number on a tape; a detecting means for detecting the latest format number; Detection means for detecting the end of data, storage means for storing the tape speed when the end of data is detected, and the time spent from detection to stop, speed control means for controlling the tape speed, and tape speed control means for controlling the tape speed. And speed control means for setting the speed.

(Operation) With the configuration described above, the present invention can quickly search even if the end area of data is skipped, and can surely search even if the end areas of new and old data are mixed.

Further, by performing the speed control at the time of rewinding the tape, it is possible to realize efficient search of the final data.

(Example) A first example of the access device of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of an access device corresponding to the first aspect of the present invention.
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, cylinder 4 and capstan 6
Is a mechanism control unit for controlling the operation of the digital camera. Reference numeral 8 denotes a digital signal which is encoded in the recording operation and supplied to the heads 5a and 5b. In the reproducing operation, a track synchronization signal is separated from the reproduced signal obtained from the heads 5a and 5b. A signal processing unit that transmits the track synchronization signal to the mechanism control unit 7, decodes the reproduction signal and outputs a digital signal, and 9 is a communication unit that transmits and receives digital data and control information to and from an external device. Reference numeral 10 denotes a data buffer for temporarily storing digital data transmitted / received by the communication unit 9. Reference numeral 11 denotes an area identification number and the number of times of formatting which are supplied as sub-data to the signal processing unit 8 in a recording operation. , A sub-data recording / reproduction control unit for extracting and outputting an area identification number and the number of times of formatting. Reference numeral 12 denotes a system control unit which receives control information from the communication unit 9 and controls a series of recording / reproducing operations. Reference numeral 13 denotes a speed control unit which transmits / receives speed information to / from the mechanism control unit 7 and the system control unit 12. Is a data end area detection section for detecting the passage of the data end area by comparing the area identification number reproduced by the sub data recording / reproduction control section 11 with the area identification number of the data end area.

15 is a system control unit 12 which is configured to
Detecting the end of data is input from the
A time measuring unit for issuing a stop command to the tape speed to be zero and measuring a time required for the tape speed to become zero.16 is a tape speed when the data end region is detected by the data end region detecting unit 14, and a time measuring unit. This is a storage unit for storing time information measured by 15. Reference numeral 17 denotes a latest format number detecting unit that detects the latest format number from the number of formats reproduced by the sub-data recording / reproduction control unit 11 and transmits the same to the system control unit 12.

The operation of the access device of the first embodiment configured as described above includes a data recording operation, a reproduction operation, and a search operation which is a high-speed reproduction operation, which will be described in detail below.

First, the data recording operation will be described. In FIG. 1, the system control unit 12 provides an area identification number and a format count to the sub-data recording / reproduction control unit 11 at the time of the recording operation, and gives an operation command to the mechanism control unit 7 and the data buffer 10; The speed information is provided to the mechanism control unit 7 via the speed control unit 13. The mechanism control unit 7 applies tension to the reel 2 according to the operation command,
The tape 3 is driven at a constant speed by rotating the capstan 6 at a constant speed, and the cylinder 4 is further rotated at a constant speed. The signal processing unit 8 processes the sub data supplied from the sub data recording / reproduction control unit 11 and the main data supplied from the data buffer 10 under the control of the system control unit 12 and adds a track synchronization signal to the track formation signal. The diagonal tracks are continuously formed on the tape 3 by converting and sequentially outputting to the heads 5a and 5b.

Next, the system control unit 12 also performs basic control for the data reproduction operation. In FIG. 1, the system control unit 12 gives an operation command to the mechanism control unit 7, and gives speed information to the mechanism control unit 7 via the speed control unit 13. The signal processing unit 8 extracts a track synchronization signal from the reproduction signals output from the heads 5a and 5b and outputs the signal to the mechanism control unit 7. The mechanism control unit 7 applies tension to the reel 2 and performs synchronous control of the rotation speed of the capstan 6 and the rotation phase of the cylinder 4 based on the track synchronization signal, thereby forming the heads 5a and 5b on the tape 3. Make the track trace exactly. On the other hand, the signal processing unit 8 processes the reproduction signal, and outputs the sub data to the sub data recording / reproduction control unit 11 and the main data to the data buffer 10, respectively. The sub-data recording / reproduction control unit 11 gives the area identification number and the number of formats, which are sub-data, to the system control unit 12, and the system control unit 12
The data recorded on the tape 3 can be accurately read by causing the communication unit 9 to sequentially start transferring the main data temporarily recorded in the data 10 as data.

Next, the system control unit 12 also performs basic control for the data search operation. In FIG. 1, the system control unit 12 gives an operation command to the mechanism control unit 7 and, at the same time, gives speed information to the mechanism control unit 7 via the speed control unit 13. The mechanism control unit 7 applies tension to the reel 2, causes the heads 5a and 5b to intermittently trace a plurality of tracks formed on the tape 3, and the signal processing unit 8 reproduces the signals output from the heads 5a and 5b. Get the signal. The signal processing unit 8 processes the reproduction signal and outputs the sub data to the sub data recording / reproduction control unit 11. The sub-data recording / reproduction control unit 11 outputs the area identification signal and the number of formats, which are sub-data, to the data end area detection unit 14, and the data end area detection unit 14 detects the data end and outputs the data end to the system control unit 12. I do.

When detecting the end of the data, the system control unit 12 controls the stop of the tape via the mechanism control unit 7, the tape speed at that time, and the time information from the detection of the end of the data measured by the time measurement unit 15 to the stop. Are stored in the storage unit 16, the speed information is calculated based on the stored tape speed and time information, output to the speed control unit 13, and the tape speed is controlled via the mechanism control unit 7.

Further, the latest format number detecting unit 17 rewinds the tape to the head from the mechanism control unit 7 via the system control unit 12 and, based on the format number and the area identification number obtained from the sub-data recording / playback control unit 11, determines the tape head area. Is output to the system control unit 12 as the latest format count.

FIG. 2 shows a configuration of a track on the tape 3 formed by the recording operation. In FIG. 2, one track indicated by A has a sub data recording area indicated by B and a track synchronization signal (Automatic Track Findin) indicated by C.
g) It comprises a recording area and a main data recording area indicated by D. On the tape 3, an even number of tracks having the same structure as the track A are continuously formed as shown by E.

FIG. 3 shows a DATA / DAT recorded by the conventional technology configuration.
Tape layout (Reference 3 “Total Overview” Appendi
x D).

Each area has an area identification number (see 8.7.
6.3 Area Codes ”(see pages 30 to 31).

Also, the number of times of formatting (Ref. 3 “8.7.6.4 Format
Count "on page 31) is the data termination area (10.4 EO in Reference 3)
Up to the area immediately before I (see P82), the number of times of formatting “i” is allocated, and in the data end area, “i−1” is allocated.

Fig. 4 shows DATA / DAT when the format is turned "j" times.
3 shows an example of a tape layout. Here, a data area formatted last time or before exists after the normal data end area.

The data end area (EOI) in the DATA / DAT format is a minimum of 32 frames (one group). When searching at a tape speed of about 200 times or more in the forward direction and 100 times or more in the reverse direction, the data end area is set as the data end area. The data may be skipped (refer to Document 1 “FIG. 6.6 Number of Unreadable Tracks at Constant Tape and Head Relative Speed Control” on page 126).

Next, there are two procedures in the search operation for the end of data, a search procedure and a speed control procedure.

First, the search procedure will be described with reference to the flowchart of FIG. 5 using the tape layout of FIG. 4 as an example.

If the latest format count has been detected in step 101, the process proceeds to step 106; otherwise, the process proceeds to step 102. In step 102, the tape is rewound to the start end, and the flow advances to step 103 to start a search in the forward direction. Next, proceed to step 104, where the area identification number is Lead in Area.
(Refer to Document 3 “10.2 Lead in Area” on page 55 to page 67) If it is not, proceed to step 105;
Continue searching in area. Here, acquiring the latest format count in Lead in Area is one of the features of DATA / DAT.
One is that the management information of the entire tape constitutes a Lead in Area (see Reference 3 “10.2.2 Header” P55 to P60) and Ma
ster Reference (Reference 3 “10.2.3 Master Reference” P6
1 to P67), and immediately after loading the tape, it is necessary to reproduce the management information first. Therefore, this operation and the operation of acquiring the latest format count are performed at once, and the search is performed reliably and quickly. It is for realizing.

Next, in step 105, the number of times of formatting of the Lead in Area is acquired as the latest number of times of formatting, and the process proceeds to step 106. In step 106, the process proceeds to step 107 when the tape search direction is the forward direction, and proceeds to step 110 when the tape search direction is the reverse direction. In step 107, if the area identification number is the data end area (EOI (see 10.3 EOI on page 82)), the process proceeds to step 113; otherwise, the process proceeds to step 108. In step 108, if the number of formats to be reproduced is not the newest number of formats, or if it is an unrecorded area, the process proceeds to step 109, and if neither, the process proceeds to step 107. In step 109, the search direction is changed to the opposite direction, and the process proceeds to step 106.

Next, in step 113, if the tape speed is equal to or less than the preset value, the process is terminated, and if it is higher, the process proceeds to step 114. In step 110, if the area identification number is the data end area (EOI), step 113
Otherwise, to step 111. At step 111, if the number of formats to be reproduced is the latest number of formats, the process proceeds to step 112; otherwise, the process proceeds to step 110. In step 112, the search direction is changed to the forward direction, and the process proceeds to step 106. Next, in step 114, when the search direction is the forward direction, the process proceeds to step 109, and when the search direction is the reverse direction, the process proceeds to step 112.

Next, the speed control procedure will be described with reference to a tape speed transition diagram at the time of searching for a data end area in FIG. 6 as an example. The vertical axis indicates the tape speed. The positive area indicates the search in the forward direction, and the negative area indicates the search in the reverse direction. The horizontal axis indicates a distance based on the start end side of the data end area. A positive distance indicates a forward direction, and a negative distance indicates a reverse direction.

Tape speed when here, in which the tape speed upon detection of the first data terminal region in the forward direction S _1, the distance when the detected after the tape is stopped once X, detects the rewinding data termination area in the opposite direction S ₂ , and the distance when the tape is temporarily stopped after detection is Y. The time spent from distance 0 to X is T ₁ , the time spent from distance 0 to Y is T _2, and S ₁
And calculating the speed information of the backward search from T ₁ Tokyo, calculates the speed of the forward search from S ₂ and T ₂ Metropolitan.

In this embodiment, after stopping the tape at a distance X, the speed S ₁ in the opposite direction to set the mechanism control unit 7, the T ₁ α (0 <α ≦
The value obtained by multiplying 1) and T _3, the time from the start of reverse search
T ₃ stand with the S ₁ beta value obtained by multiplying the (0 <β ≦ 1) and S _3, to continue the backward search. Note that the forward search from the distance Y is also
The same processing is performed.

Next, a second embodiment of the access device of the present invention will be described with reference to the drawings.

First, FIG. 7 shows a configuration of an access device corresponding to the second aspect of the present invention. In FIG. 7, 1 is a cassette half, 2 is a reel, 3 is a tape,
Is a cylinder, 5a and 5b are heads, 6 is a capstan for running the tape 3, 7 is a reel 2 and a cylinder 4 is a mechanism control unit for controlling the operation of the capstan 6, and 8 is a digital signal for recording operation. The recording signals are supplied to the heads 5a and 5b, and in the reproducing operation, the track synchronizing signal is separated from the reproducing signal obtained from the heads 5a and 5b, and the track synchronizing signal is transmitted to the mechanism control unit 7.
A signal processing unit for decoding a reproduced signal and outputting a digital signal, a communication unit 9 for transmitting and receiving digital data and control information to and from an external device, and a temporary storage of digital data transmitted and received by the communication unit 9 A data buffer 11 supplies an area identification number as sub-data to the signal processing unit 8 in a recording operation, and extracts and outputs an area identification signal in a reproduction operation. Reference numeral 12 denotes a system control unit which receives control information from the communication unit 9 and controls a series of recording / reproducing operations. Reference numeral 13 denotes a speed control unit which transmits / receives speed information to / from the mechanism control unit 7 and the system control unit 12. Is a data end area detection section for detecting passage of the data end area by comparing the area identification signal reproduced by the sub data recording / reproduction control section 11 with the area identification number of the data end area. Reference numeral 15 denotes a time measuring unit that measures the time that the system control unit 12 uses to input the detection of the end of the data from the data end region detection unit 14 and issue a stop command to the mechanism control unit 7 to reduce the tape speed to zero. Reference numeral 16 denotes a storage unit that stores a tape speed when the data end area is detected by the data end area detection unit 14 and time information measured by the time measurement unit 15. Reference numeral 18 denotes a start-end search start detection unit that detects from the mechanism control unit 7 that a tape has been newly loaded into the mechanism, and outputs a start of start-end search to the system control unit 12.

The operation of the access device of the second embodiment configured as described above includes a data recording operation, a reproducing operation, and a search operation, which is a high-speed reproducing operation, and will be described in detail below.

First, the data recording operation will be described. In FIG. 7, the system control unit 12 provides an area identification number to the sub-data recording / reproduction control unit 11 during a recording operation, and provides an operation command to the mechanism control unit 7 and the data buffer 10;
The speed information is provided to the mechanism control unit 7 via the speed control unit 13. The mechanism control unit 7 applies tension to the reel 2 according to the operation command, and drives the tape 3 at a constant speed by rotating the capstan 6 at a constant speed.
Further, the cylinder 4 is rotated at a constant speed. The signal processing unit 8 processes the sub data supplied from the sub data recording / reproduction control unit 11 and the main data supplied from the data buffer 10 under the control of the system control unit 12 and adds a track synchronization signal to the track formation signal. Convert to head 5
The diagonal tracks on the tape 3 are successively formed by sequentially outputting the signals to a and 5b.

Next, the system control unit 12 also performs basic control for the data reproduction operation. 7, the system control unit 12 gives an operation command to the mechanism control unit 7, and gives speed information to the mechanism control unit 7 via the speed control unit 13. The signal processing unit 8 extracts a track synchronization signal from the reproduction signals output from the heads 5a and 5b and outputs the signal to the mechanism control unit 7. The mechanism control unit 7 applies tension to the reel 2 and performs synchronous control of the rotation speed of the capstan 6 and the rotation phase of the cylinder 4 based on the track synchronization signal, thereby forming the heads 5a and 5b on the tape 3. Make the track trace exactly. On the other hand, the signal processing unit 8 processes the reproduction signal, and outputs the sub data to the sub data recording / reproduction control unit 11 and the main data to the data buffer 10, respectively. The sub-data recording / playback control unit 11 gives the area identification number, which is sub-data, to the system control unit 12, and the system control unit 12 sends the main data temporarily recorded in the data buffer 10 as data to the communication unit 9 sequentially. By starting the transfer, the data recorded on the tape 3 can be accurately read.

Next, the system control unit 12 also performs basic control for the data search operation. In FIG. 7, the system control unit 12 gives an operation command to the mechanism control unit 7 and, at the same time, gives speed information to the mechanism control unit 7 via the speed control unit 13. The mechanism control unit 7 applies tension to the reel 2, causes the heads 5a and 5b to intermittently trace a plurality of tracks formed on the tape 3, and the signal processing unit 8 reproduces the signals output from the heads 5a and 5b. Get the signal. The signal processing unit 8 processes the reproduction signal and outputs the sub data to the sub data recording / reproduction control unit 11. The sub data recording / reproduction control unit 11 outputs the area identification number, which is sub data, to the data end area detection unit 14, and the data end area detection unit 14
The data end is detected and output to the system control unit 12. When detecting the end of the data, the system control unit 12 controls the stop of the tape via the mechanism control unit 7. Are stored in the storage unit 16, the speed information is calculated based on the stored tape speed and time information, output to the speed control unit 13, and the tape speed is controlled via the mechanism control unit 7.

Further, the start-end search start detecting unit 18 is provided with the mechanism control unit 7.
It detects that the tape has been loaded and outputs it to the system control unit 12 as information for rewinding the tape to the beginning.

FIG. 8 shows a DDS tape layout recorded according to a conventional technology configuration (see Document 5, “10. Tape Layout”, pp. 55-68). Each area is assigned an area identification number (see “8.2.1.1 Area ID” on pages 3 to 26 in Literature 3).

FIG. 9 shows an example of a DDS tape layout when formatting is performed a plurality of times. Here, a data area formatted last time or before exists after the normal data end area.

In addition, the data termination area (EO
D) is a minimum of 300 frames (Reference 5 “10.4.1.1 EOD Length”
and Position "(see page 59), and the data end area is not skipped at the time of retrieval (see" Refer to FIG. 6.6, "Fig. 6.6 Number of Unreadable Tracks at Constant Tape and Head Relative Speed Control" P126).

Next, there are two procedures in the search operation for the end of data, a search procedure and a speed control procedure.

First, the search procedure will be described using the tape layout of FIG. 9 as an example and FIG. 10 using a flowchart.

If it is detected in step 201 that this is the first search after the tape has been loaded, the flow proceeds to step 203; otherwise, the flow proceeds to step 202. In step 202, the tape is rewound to the start end, and the flow advances to step 203 to start a forward search. In step 203, if the tape search direction is the forward direction, the process proceeds to step 204, and if the tape search direction is the reverse direction, the process proceeds to step 207. In step 204, if the area identification number is the data end area (EOD), step 2
Go to step 09, otherwise go to step 205. In step 205, if the area is an unrecorded area, the process proceeds to step 206; otherwise, the process proceeds to step 204. In step 206, the search direction is changed in the opposite direction, and the process proceeds to step 203. Next, at step 209, if the tape speed is equal to or less than the preset value, the process is terminated, and if it is higher than the preset value, the process proceeds to step 210. In step 207, if the area identification number is the data end area (EOD), the process proceeds to step 208; otherwise, the process proceeds to step 207. Step 2
At 08, the search direction is changed to the forward direction, and the routine proceeds to step 203. Next, in step 210, the process proceeds to step 206 if the search direction is the forward direction, and proceeds to step 208 if the search direction is the reverse direction.

Also, the speed control procedure is the same as in the first embodiment, and a description thereof will be omitted.

The mechanism control unit 7, the sub-data recording / playback control unit 11, the system control unit 12, the speed control unit 13, the data end area detection unit 14, the time measurement unit 15, the storage unit 16, the latest format number detection unit 17, the start end search Although the start detection units 18 are independent control units, some of them may be integrated into a microcomputer and realized as software.

(Effects of the Invention) The access device of the present invention comprises a communication means, a first recording means for forming a data block area on a tape, a second and third means for recording an area identification number and a format count in a specific area. Recording means and the first and second reproducing means for reproducing recorded data.
Playback means, and a first means for detecting the latest format count
, A first comparing means for comparing the target area identification number with the area identification number reproduced by the reproducing means, and comparing the latest format number with the number of formats reproduced by the reproducing means. Second comparing means, second detecting means for detecting that the reproduced data area is an unrecorded area, and third detecting means for detecting passage of a data block in which a target area identification number is recorded. Detecting means, fourth detecting means for detecting the start of a search for a target area identification number, time measuring means for measuring an arbitrary time, storage means for storing tape speed and time information, With the provision of the speed control means for controlling the search direction and speed, it is possible to reliably search for the end of the legitimate data, perform the speed control accordingly, and control the speed of rewinding. Spend can exhibit excellent characteristics such as a reduction in time can be easily realized, the effect of the practical is atmospheric.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an access device in an embodiment according to the first aspect of the present invention, FIG. 2 is a configuration diagram of a tape format, and FIG. FIG. 4 is a block diagram of a DATA / DAT tape layout (at the time of the first format), and FIG. 4 is a block diagram of a DATA / DAT tape layout (at the time of a plurality of formats) recorded by the conventional technology. 5
FIG. 6 is a flowchart of the search for the end of DATA / DAT data, FIG. 6 is a diagram showing a tape speed transition at the time of searching for the end of data, and FIG. 7 shows the configuration of the access device in the embodiment according to the second aspect of the present invention. FIG. 8 is a block diagram of a DDS tape layout recorded by the conventional technology configuration (at the time of the first formatting), and FIG. 9 is a DDS tape layout recorded by the conventional technology configuration (a plurality of times). Fig. 10 shows DDS
9 is a flowchart of a search for the end of data. 1 ... cassette half, 2 ... reel, 3 ... tape,
4 ... cylinder, 5a, 5b ... head, 6 ... capstan, 7 ... mechanism control unit, 8 ... signal processing unit, 9 ...
... Communication unit, 10 ... Data buffer, 11 ... Sub data recording / playback control unit, 12 ... System control unit, 13 ... Speed control unit, 14 ... Data end area detection unit, 15 ... Time measurement unit,
16: Storage unit, 17: Latest format count detection unit, 18
... Start-end search start detection unit.

Claims (5)

(57) [Claims] 1. A communication means for transmitting and receiving digital data and control information from an external device, and a set of frames comprising a plus azimuth track and a minus azimuth track, wherein a data block area containing data obtained from said communication means is recorded on a tape. First recording means, an area identification number which is an identification number of a data area which is a set of one or more data blocks, and a format number indicating the number of times of formatting of a tape are predetermined on a track. Second recording means for recording in the designated specific area, data recorded by the first recording means,
A first reproducing means for continuously or intermittently reproducing a plus azimuth track and a minus azimuth track at a preset speed with the area identification number and the number of formats recorded by the second recording means; First detecting means for detecting the latest format number from among the number of formats reproduced by the first reproducing means; a target area identification number; and an area identification number reproduced by the first reproducing means. First comparing means for comparing the number of latest formats detected by the first detecting means with the number of formats reproduced by the first reproducing means; and Second detecting means for detecting that the data area reproduced by the first reproducing means is an unrecorded area; and the first and second comparison means. A third step of detecting the passage of the data block in which the target area identification number is recorded, based on the comparison result of the step and the detection by the second detecting means;
Detecting means, a time measuring means for measuring a time taken to stop the tape from the detection by the third detecting means, and a storing means for storing a tape speed and time information measured by the time measuring means. An access device comprising: a tape control unit configured to control a tape search direction and a speed based on the tape speed and time information stored in the storage unit and the third detection unit. 2. A set of frames comprising a communication means for transmitting and receiving digital data and control information from an external device, and a frame composed of a plus azimuth track and a minus azimuth track. And a third recording means for recording at least one area identification number, which is an identification number of a data area, which is a set of the data blocks, in a predetermined specific area on a track. The data recorded by the first recording device and the area identification number recorded by the third recording device are continuously or intermittently recorded at a preset speed at a plus azimuth track and a minus azimuth track. Second reproducing means for reproducing the target area, and detecting the start of the search for the target area identification number 4
Detecting means, a target area identification number, a first comparing means for comparing the area identification number reproduced by the second reproducing means, and an area of data reproduced by the second reproducing means. Is a non-recorded area, and the target area identification number is recorded based on the comparison result of the first comparison means and the detection by the second detection means. Fifth detecting means for detecting passage of the data block, time measuring means for measuring a time taken for the tape to stop from detection by the fifth detecting means, tape speed and time measured by the time measuring means. Storage means for storing time information; tape speed and time information stored in the storage means; and a speed control means for controlling a tape search direction and speed based on the fifth detection means. An access device, characterized in that: And a storage means for detecting a target area identification number, a format number different from the latest format number, or an unrecorded area when the tape search method is the forward direction by the first comparing means. And a second storage procedure for storing the target area identification number or the tape speed when detecting the latest format count in the reverse direction. The access device according to claim 1, wherein: 4. A storage means for storing a target area identification number or a tape speed for detecting an unrecorded area when the tape search method is the forward direction by the first comparison means. 3. The access device according to claim 2, further comprising a fourth procedure for storing a tape speed for detecting a target area identification number in the case of a reverse direction. 5. The speed control means comprises: a calculation procedure for calculating speed information based on a tape speed and time information stored in a storage means; and a setting procedure for setting the speed control means. The access device according to claim 1 or 2, wherein