JP3514494B2 - Magnetic tape unit - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic tape device for recording data from a host device on a magnetic tape by a write / read head and for reading data recorded on the magnetic tape.

[0002]

2. Description of the Related Art In a computer or the like, a large amount of data processed by the computer is recorded on a magnetic tape, and the data recorded on the magnetic tape is read and processed when necessary.

Recording of data on a magnetic tape is shown in FIG.
As shown in (A), a series of data to be recorded is recorded for each data block divided in a certain unit. As shown in FIG. 7B, the data block includes a code “ALL1” indicating the beginning of the data block, a “SYNC” indicating the beginning of the data, a data “DATA”, and a data next. It is composed of a code "SYNC" indicating the end, an ID number "ID" indicating the ID of the data block next, and a code "ALL1" indicating the end of the data block at the end.

Further, as shown in FIG. 7A, a tape mark is recorded at a delimiter of a file consisting of a series of data blocks. As shown in FIG. 7C, when the magnetic tape is damaged and data cannot be recorded, the damaged block is skipped as an erase block for a certain length and the next data block is recorded. I am letting you.

In the conventional magnetic tape device, the host device issues a command to locate the head at the ID number N (locate command) and a command to locate the head at the next or next file (space file command). When receiving the ID, the magnetic tape device sequentially reads the ID numbers of the data blocks while moving the magnetic tape, and when the read ID number matches the specified ID number, the tape of the next or next next file is read. When the mark was detected, the drive of the magnetic tape was stopped to perform positioning.

Further, when recording data on a magnetic tape, the recorded data is read to detect whether or not a recording error has occurred, and if there is a recording error, recording is performed again at the same location. The process of detecting whether or not there is a recording error was repeated several times. If a recording error occurs even after repeating a few times, it is assumed that the magnetic tape is damaged, and recording is performed to indicate that the block is a fixed length erase block, and the data block is skipped, and a data block is recorded at the next position.

[0007]

As described above, in the conventional magnetic tape device, when the locate command is transferred from the host device, the magnetic tape device drives the magnetic tape and records it on the magnetic tape. The data that has been read is sequentially read out, and when the ID number of the read data block or the tape mark of the file matches the specified one, the data is stopped and positioned.

Therefore, it takes a long time to position at the designated position. Also, when recording the data again on the magnetic tape, Oite in a location where there is damage,
The same processing was performed as when the erase block was skipped on the new magnetic tape, and it took a long time to record the data.

The present invention provides an improved magnetic tape apparatus for shortening the time required for positioning the magnetic tape with respect to the write / read head when positioning the magnetic tape with respect to the write / read head in accordance with the locate command. Is the first purpose. It is an object of the present invention to provide an improved magnetic tape device which shortens the time required to position the magnetic tape with respect to the write / read head when positioning the magnetic tape with respect to the write / read head according to the space file command. The purpose is 2.

[0010]

The means adopted by the present invention for attaining the above-mentioned first object is, as shown in the principle diagram of the present invention in FIG. data subjected to the data block ID number for each record in the magnetic <br/> care tape, in reading the magnetic tape apparatus the recorded data from the magnetic tape, (a) the magnetic tape is the write and read sequentially and tape position signal generating means (1) for generating at a predetermined tape position signals indicative of the tape position predetermined in the magnetic tape passing through the head, when recording of data to the (b) said magnetic tape, said before so as to correspond to a signal indicating the tape position for each tape position signal generating means (1) generates a signal indicating the tape position
Serial and tape position ID recording means for recording the ID number of the data blocks recorded on the tape position of the magnetic tape (2), when receiving a locate command from (c) the host device, in the Locate command thus received the <br/> data the block closest to the ID number in the ID number is recorded the signal indicating the tape position tape position I designated
Read from D recording means (2), is driven at a high speed the magnetic tape to the said same signal as a signal indicating the tape position tape position signal generating means (1) is generated that issued said read, then the magnetic tape Drive at low normal speed
The data block recorded on the magnetic tape
Read the ID number of the
The ID number of the data block issued is the locate code.
ID number of the data block specified by the command
When doing so, stop the drive of the magnetic tape and position it
Locating command positioning means (3) for terminating .

Further, the means for the present invention is employed to achieve the second object described above, as shown in principle diagram of the present invention in FIG. 1, the write and read head, the data block data from the host apparatus A series of ID numbers are attached to each
A table showing the delimiter of the file consisting of the data blocks.
Recorded on the magnetic tape are denoted by the Pumaku, said recorded in reading the magnetic tape device data from the magnetic tape, (a) the magnetic tape is a magnetic tape a signal indicating the tape position passing through the write and read head sequential tape position signal generating means (1) for generating at a predetermined predetermined tape position, (b) at the time of recording data to the magnetic tape, the tape position signal generating means (1) the tape position before so as to correspond to a signal indicating the tape position for each for generating a signal indicating
A serial tape position ID recording means for recording the ID number of the data blocks recorded on the tape position of the magnetic tape (2), are recorded before or after the tape mark recorded in (c) said magnetic tape ID of the data block
A tape mark ID recording means for recording the number (4), corresponding in (d) of the when receiving space file command from the host device, the file specified by the space file piece <br/> command thus received read from the tape mark ID recording means the ID number of the data block to the tape mark (4) which, issued said read
Said tape position most the closest ID number is recorded <br/> read from the tape position ID recording section of the tape position (2), said read the same signal and the signal indicative of the tape position that issued the ID number Until the signal generation means (1) is generated
The magnetic tape is driven at high speed, and then the magnetic tape is
Drive at a low normal speed to record on the magnetic tape.
Write and read the ID number of the data block
The data is read by the output head and the read data block is read.
The ID number of the clip is the tape mark corresponding to the file.
Before when the ID number of the corresponding data block matches
Serial includes a space file command position with means you exit the positioned stops driving the magnetic tape (5), a.

[0012]

The tape position signal generating means 1 uses a magnetic tape for writing.
A signal indicating the position of the tape passing through the read / write head is sent to
Order at a predetermined tape position of the air tape
It occurs next . Tape position ID recording means 2, the when recording data to the magnetic tape, corresponding to the signal indicating the tape <br/> flop position for each of the tape position signal generating means 1 generates a signal indicative of the tape position It is allowed to record the ID number of the recorded data block to the tape position of the magnetic tape.

When the locate command locating means 3 receives a locate command from the host device, the data block ID designated by the received locate command.
Nearest the ID number is recorded the signals indicative of the tape position read from the tape position ID recording means 2, the same signal as the signal indicative of the read said tape position the tape position signal generating means 1 generates the number is driven at a high speed the magnetic <br/> tape until, after the magnetic tape slow
Recorded on the magnetic tape by driving at the normal speed of
The ID number of the data block is written in the write / read head.
And the ID of the read data block
The database whose number is specified in the locate command
When the lock ID number matches, drive the magnetic tape.
Stop and finish positioning .

As described above, the ID number of the data block recorded at the tape position of the magnetic tape is recorded in correspondence with the signal indicating the tape position passing through the write / read head, and when the locate command is transferred. , A signal indicating the tape position at which the ID number closest to the ID number of the data block specified by the ID number locate command closest to the specified ID number is recorded is the tape position ID.
Since the magnetic tape is read out from the recording means 2 and the same signal as the read-out tape position signal is generated by the tape position signal generating means 1 at high speed, the magnetic tape is positioned at a designated position in a short time. You can

When data is recorded on the magnetic tape, when a signal indicating the tape position is generated by the tape position signal generating means 1, the tape position signal is generated at the tape position corresponding to the signal indicating the tape position. The tape position ID recording means 2 records the ID number of the recorded data block.
When the recording of the series of data blocks is completed and the tape mark is recorded on the magnetic tape, the tape mark ID recording means 4 indicates the tape mark indicating the delimiter of the file composed of the series of data blocks recorded on the magnetic tape. The ID number of the data block recorded before or after is recorded.

When a space file command for positioning the next or next next file is transferred from the host device, the space file command positioning means 5 gives the ID number of the data block for the tape mark corresponding to the file designated by the command. The magnetic tape is read at a high speed from the tape mark ID recording means 4 until the tape position signal generating means 1 generates the same signal as the signal indicating the tape position where the ID number closest to the read ID number is recorded. Drive the magnetic tape and then
Drive at a low normal speed to record on the magnetic tape.
Write and read the ID number of the data block
The data is read by the output head and the read data block is read.
The ID number of the clip is the tape mark corresponding to the file.
Before when the ID number of the corresponding data block matches
The magnetic tape drive is stopped and the positioning is completed .

As described above, the ID number of the data block recorded at the tape position on the magnetic tape and the file delimiter consisting of a series of data blocks recorded on the magnetic tape are shown in correspondence with the signal indicating the tape position. The ID number of the data block recorded before or after the tape mark is recorded, and when the space file command is transferred, the ID number for the tape mark corresponding to the specified file is read out and is the closest to the read ID number. Since the magnetic tape is driven at a high speed to the tape position where the same signal as the signal indicating the tape position where the ID number is recorded is generated, the positioning to the designated file can be performed in a short time. Can be done.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 2 is a block diagram of the embodiment of the present invention, FIG. 3 is an operation flowchart for writing data in the embodiment, FIG. 4 is an operation flowchart for a locate command in the embodiment, and FIG. 5 is a space file in the embodiment . FIG. 6 is an operation flow chart at the time of command start, and FIG. 6 is an operation flow chart at the start and end of the apparatus operation of the embodiment.

In FIG. 2, 11 is a sector for recording the ID number of the data block recorded at the tape position of the magnetic tape in correspondence with the sector signal which is a signal indicating the tape position where the magnetic tape passes the write / read head. An ID recording unit, 12 is a sector ID writing unit for recording an ID number in the sector ID recording unit 11, 13 is a locate command positioning unit for positioning the head when a locate command is transferred, and 14 is an ID number corresponding to a tape mark. , 15 is a tape mark ID recording section for recording an ID number in the tape mark ID recording section 14, 16 is a space file command positioning section for positioning the head when a space file command is transferred, An erase ID recording unit 17 records an ID number corresponding to an erase block. 18 erase ID recording unit 1
An erase ID writing section for recording an ID number in 7, an erase block skip section for skipping an erase block at the time of writing data, 20 a sector counter, 21
Is a tape mark counter, 22 and 23 are interfaces (I / O), 24 is a control unit, and 25 is a processor (CPU) for processing.

Reference numeral 31 designates a host I / O control section which acts as an interface with the host device, and 32 designates a data block, erase block, IBG (Internal Bloat) during recording.
a write formatter (WFMT) 33 for generating a pattern of a ck gap) and controlling the sequence thereof, a data I / O control unit 31 for extracting data of a data block at the time of reading.
, A read formatter (RFMT) for transferring to the data memory 31b, a write / read head for writing data to the magnetic tape 36, and a read / write head for reading data from the magnetic tape 36, and a sector signal generator 38 for generating a sector signal. , 37 are drive units for rotating the reels 35a, 35b to move the magnetic tape 36.

Command memory 31 of host I / O controller 31
The command transferred from the host device is recorded in a, and the write data and the read data are recorded in the data memory 31b. In the sector signal generator 38, the reels 35a,
A pulse signal is generated when the ratio of the radii r ₁ and r ₂ of the magnetic tape wound around 35b reaches a preset value.

The set value of the ratio of r ₁ and r ₂ is set such that the total length of the magnetic tape 36 is divided into 72, for example. Next, with reference to FIG. 3, the operation when the data write command is transferred from the host device and the data is recorded on the magnetic tape will be described.

In step S10, the control section 24 will be described later with reference to FIG.
The magnetic tape 36 of the head 34 based on the processing described in
Position the write start position for. In processing S11, the control unit 24 reads the ID number of the data block recorded before or after the positioned magnetic tape position with the RFMT 33, and the sector value corresponding to the read ID number is read from the sector ID recording unit 11 by the sector ID recording unit 11. Also, I read
The tape mark value corresponding to the D number is read from the tape mark ID recording section 14 and set in the sector counter 20 and the tape mark counter 21, respectively.

The recorded data in the sector ID recording section 11 and the tape mark ID recording section 14 will be processed later in step S1.
8 and S23. In step S12, the data writing process is started, and the erase block skip unit 19 is started.
Determines whether or not the ID number recorded in the erase ID recording unit 17 and the ID number generated in the WFMT 32 and written in the next data block match, and if YES, the process proceeds to step S13 and fixed. The control unit 24 is instructed to skip the long magnetic tape.

When the control section 24 receives the skip command, the W
The FMT 32 is notified and the drive unit 37 is instructed via the I / O 23 to skip the magnetic tape for a certain length. Also, for skipped data blocks, WFMT
32 records a code indicating a skip block.

In step S14, a normal writing process is executed to write data on the magnetic tape 36. Process S
In 15, the control unit 24 determines whether or not a writing error occurs in the writing process in the process S15, and if an error occurs and writing is performed again, if the error occurs again, the process is performed. In step S16, the block in which the error has occurred is set as an erase block, and the fixed length magnetic tape is skipped.

In step S17, the erase ID writing unit 18
Reads the ID number generated for recording in the next data block by the WFMT 32, additionally records the last data of the data recorded in the erase ID recording section 17, and moves to the processing S21. If the write error occurs in this way due to damage of the magnetic tape, a note of the ID number corresponding to the generated data block, when the case of recording data occurs in the same tape position again, step S12
Then, the erase block is detected and skipped in step S13, the determination in step S15 is set to YES, the skip step S in step S16 that requires a long time is avoided, and the next data block is positioned in a short time. can do.

In the embodiment, the erase ID recording section 17
Although the ID number of the data block next to the erase block is recorded as the ID number recorded in the above, the ID number of the data block before the erase block may be recorded. In step S18, the sector ID
The writing unit 12 determines whether or not a sector signal is generated by the sector signal generation unit 38, and if the determination is NO, the process S21.
If YES, the process moves to step S19.

In step S19, the sector ID writing unit 12
Increments the count value S of the sector counter 20 by one. That is, the count value of the sector counter corresponds to the number of the signal generated by the sector signal generator 38.

In process S20, the sector ID writing unit records the ID number of the data block generated in the WFMT 32 in the memory whose address in the sector ID recording unit 11 corresponds to the count value S of the sector counter 20 and processes it. S21
Move on to. In step S21, the control unit 24 controls the series of data.
It is determined whether or not the writing of the block (file) is completed. If the determination is NO, the process proceeds to step S12, and steps S12-
S21 is returned Repetitive, if the determination is YES, WFMT3
2 records a tape mark on a magnetic tape as shown in FIG.

In process S22, the erase ID writing unit 18
Increments the count value M of the tape mark counter 21 by one. In step S23, the erase ID writing unit 18 determines that the address of the erase ID recording unit 17 is the tape mark counter 2
The ID number of the data block generated in the WFMT 32 is recorded in the memory corresponding to the count value of 1, and the writing process ends.

[0032] Note that when the tape mark ID recording, if the tape mark is increased by performing the re-writing of data to the magnetic tape, re-record perform ID numbers that are previously written in sequential deferred Be done. Next, with reference to FIG. 4, an operation in which the locate command is transferred from the host device and the head is positioned will be described.

In step S30, the locate command positioning unit 13 reads the ID number of the data block recorded on the magnetic tape 36 from the RFMT 33, and determines the sector ID.
The sector number of the current head position is calculated with reference to the ID number recorded in the recording unit 11, and the calculated sector number is set in the sector counter 20.

Next, in step S31, the sector number S, which is the ID number closest to the ID number designated by the host device.
_A is calculated with reference to the recording of the sector ID recording unit 11.
In step S32, the control unit 24 drives the magnetic tape at high speed command to the drive unit 37.

In step S33, the locate command positioning unit 13 determines whether or not a sector signal is input from the sector signal generation unit 38 via the I / O 23, and the determination is NO.
If YES, the process proceeds to step S32 to continue high-speed driving. If the determination is YES, the process proceeds to step S34 and the sector counter 2
The count value S of 0 is incremented by 1.

If the high speed drive in the process S32 is the reverse drive, -1 is added in the process S34. Process S3
In 5, the locate command positioning unit 13 determines whether or not the count value S of the sector counter 20 and the sector number S _A calculated in the process S31 match. If the determination is NO, the process moves to the process S32. S32 to S35 are repeated, and if the determination is YES, the process proceeds to S36.

In step S36, the control section 24 causes the drive section 37 to operate.
To drive the magnetic tape at a low speed, that is, at the speed of normal reading and writing. In step S37, RFMT33
Data block ID number from the magnetic tape via
Read _R , ID number specified by the host in process S38
It is determined whether the number and the ID number ID _R match, and if they do not match, the process proceeds to step S36 and steps S36 to S38 are repeated. If they match, the process proceeds to step S39 to stop the drive of the magnetic tape and Finish positioning.

Next, the operation when the space file command is transferred from the host device will be described with reference to FIG. In step S50, the space file command positioning unit 16 reads the ID number of the data block recorded on the magnetic tape from the RFMT 33, and reads the sector ID.
The sector number S and the tape mark number M at the current head position are calculated with reference to the ID numbers recorded in the recording unit 11 and the tape mark ID recording unit 14, and the calculated S is calculated.
And M are set in the sector counter 20 and the tape mark counter 21, respectively.

In step S51, the space file command positioning unit 16 calculates the tape mark number M _A corresponding to the file designated by the host device. That is,
When the positioning command is transferred to the next file from the host device, the value obtained by adding +1 to the count value M of the tape mark counter 21 becomes M _A.

In process S52, the space file command positioning unit 16 reads the ID number corresponding to the tape mark number M _A calculated in process S51 from the tape mark ID recording unit 14, and then in process S53, in process S52. The sector number S _{A in} which the ID number closest to the read ID number is recorded is calculated with reference to the recording of the sector ID recording unit 11.

In step S54, the control section 24 controls the drive section 3
7 to drive the magnetic tape at high speed. Process S5
5, the space file command positioning unit 16 uses the I
It is determined whether or not there is a sector signal interrupt from the sector signal generation unit 38 via the / O23. If the determination is NO, the process proceeds to step S54, and if the determination is YES, the process proceeds to step S56 and the sector counter 20 The count value S is incremented by 1.

In the process S57, it is determined whether or not the sector number S _A calculated in the process S53 and the count value S of the sector counter 20 match, and if NO, the process S54.
If YES, the process moves to step S58. Process S58
Then, the control unit 24 instructs the drive unit 37 to drive the magnetic tape at a low speed.

In step S59, the magnetic field is transmitted via RFMT33.
ID number I of the data block that has been recorded in the care tape
D _R reads, proceeds to the processing S60, I read I from the magnetic tape by the ID number and the processing S59 calculated by the processing S52 I
It is determined whether or not the D number ID _R matches, and the determination is NO.
If yes, then the process proceeds to step S58; if YES, then the process S61.
Magnetic to see a record of the tape mark of the magnetic tape is moved to
The drive of the air tape is stopped and the process S is ended.

The setting of the sector count S in the processing S30 of FIG. 4 and the processing S50 of FIG. 5 may be removed if it is set to start the operation of the magnetic tape device. Next, referring to FIG. 6, the operation starts and the processing ends or when the magnetic tape drive when the ID number of the tape device.

In step S70, when the magnetic tape is set and the operation is started, first, the ID number corresponding to the sector number is read and recorded in the sector ID recording section 11 from the head of the magnetic tape or when instructed. Next, step S7
In No. 1, similarly, the ID number corresponding to the tape mark number is read from the magnetic tape and recorded in the tape mark ID recording unit 14.

Further, in the process S72, the ID number (erase I) corresponding to the erase block is also read from the magnetic tape.
D) is read and recorded in the erase ID recording unit 17. When the recording is completed, the process proceeds to step S73, and the normal writing / reading process is executed. In step S74, replacement with a different magnetic tape and power-off of the magnetic tape device are performed.
If the operation of the device is stopped, the process proceeds to step S75.

In step S75, the ID number (sector ID) recorded in the sector ID recording section 11 is read and recorded in the area of the magnetic tape read in step S70. In processes S76 and S77, the ID numbers (tape mark ID and erase) recorded in the tape mark ID recording unit 14 and the erase ID recording unit 17, respectively.
ID) is read and recorded on the magnetic tape, and the process S is completed.

In this way, the sector ID and tape mark I
By recording the D and the erase ID on the magnetic tape and reading them out at the start of the operation and recording them in each recording section, the sector ID, tape mark ID and erase ID for the data recorded on the magnetic tape can be easily obtained. be able to.

Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and various modifications can be made according to the gist of the invention.

[0050]

As described above, according to the present invention, which has been made to achieve the first object, the tape is read every time the magnetic tape passes the write / read head and generates a signal indicating the tape position. position to correspond to the signal indicating to record the ID number of the data blocks recorded on the tape position of the magnetic tape, b if locate command was specifically be forwarded, b
Since the signal indicating the tape position that has the ID number closest to the ID number specified by the GATE command is read and the magnetic tape is driven at high speed up to the read tape position, the magnetic tape can be positioned at the specified position in a short time. You can
According to the present invention made to achieve the second object, each time the magnetic tape passes the write / read head and generates a signal indicating the tape position, the magnetic tape of the magnetic tape is caused to correspond to the signal indicating the tape position. The ID number of the data block recorded at the tape position and the ID of the data block recorded before or after the tape mark indicating the delimiter of the file consisting of a series of data blocks recorded on the magnetic tape.
The number is recorded and the space file command is transferred.
Then, the ID number of the data block for the tape mark corresponding to the file specified by the space file command is read, and the I number closest to the read ID number is read.
Since the tape position where the D number is recorded is read and the magnetic tape is driven at a high speed to the read tape position, the position of the designated file can be determined in a short time.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a configuration diagram of an embodiment of the present invention.

FIG. 3 is an operation flowchart at the time of writing data in the embodiment.

FIG. 4 is an operation flowchart at the time of a locate command in the embodiment.

FIG. 5 is an operation flowchart for a space file command in the embodiment.

FIG. 6 is an operation flowchart at the start and end of the operation of the apparatus of the embodiment.

FIG. 7 is a specific example of data recording on a magnetic tape.

[Explanation of symbols]

1 tape position signal generating means 2 tape position ID recording means 3 Locate command positions with means 4 tape mark ID recording means 5 a space file command position with hands stage 11 sector ID recording unit 12 sector ID writing unit 13 Locate command position with portions 14 tape mark ID recording unit 15 tape mark ID writing unit 16 space file command position with section 20 sectors counter 21 tape mark counter 22 and 23 interface (I / O) 24 control unit 25 the processor (CPU) 31 host I / O Control unit 32 Write formatter (WFMT) 33 Read formatter (RFMT) 34 Write / read head 35 Reel 36 Magnetic tape 37 Drive unit 38 Sector signal generation unit

Claims (5)

(57) [Claims] By 1. A write and read head, and recorded on the magnetic tape are denoted by the ID number data for each data block from the host device, in reading the magnetic tape unit from the magnetic tape the recorded data, ( sequentially and tape position signal generating means (1) for generating at a signal indicating the tape position where a) the magnetic tape passes the write and read head a predetermined tape position a predetermined of said magnetic tape, (b) the at the data to the magnetic tape recording, the tape position signal generating means (1) before in association with a signal indicating the tape position for each for generating a signal indicating the tape position
Serial and tape position ID recording means for recording the ID number of the data blocks recorded on the tape position of the magnetic tape (2), when receiving a locate command from (c) the host device, in the Locate command thus received the <br/> data the block closest to the ID number in the ID number is recorded the signal indicating the tape position tape position I designated
Read from D recording means (2), is driven at a high speed the magnetic tape to the said same signal as a signal indicating the tape position tape position signal generating means (1) is generated that issued said read, then the magnetic tape Drive at low normal speed
The data block recorded on the magnetic tape
Read the ID number of the
The ID number of the data block issued is the locate code.
ID number of the data block specified by the command
When doing so, stop the drive of the magnetic tape and position it
A locate command positioning means (3) for terminating, and a magnetic tape device. 2. A signal indicating the tape position the tape position signal generating means (1) occurs, it is a sector signal generated on the basis of diameter values of the magnetic tape which is wound on the take-up reel The magnetic tape device according to claim 1, wherein: The method according to claim 3, wherein the ID number recorded on the tape position ID recording means (2), is recorded on the magnetic tape during operation the end of the magnetic tape device, before being the recording
Serial ID number tape device according to claim 1, wherein in that from the magnetic tape at the start of operation of the magnetic tape apparatus so as to record on the tape position ID recording means reads (2). 4. A write / read head attaches an ID number to data from a host device for each data block.
A file delimiter consisting of a series of the above data blocks
Were recorded on the magnetic tape are denoted by the tape mark indicating signal indicating in the recorded reading magnetic tape unit from the magnetic tape data, the tape position that passes through (a) the magnetic tape is the write and read head the tape position signal generating means for sequentially generating the predetermined predetermined tape position of the magnetic tape (1), (b) the at the time of recording data to the magnetic tape, the tape position signal generating means (1) is the before so as to correspond to a signal indicating the tape position for each for generating a signal indicating the tape position
A serial tape position ID recording means for recording the ID number of the data blocks recorded on the tape position of the magnetic tape (2), are recorded before or after the tape mark recorded in (c) said magnetic tape ID of the data block
A tape mark ID recording means for recording the number (4), corresponding in (d) of the when receiving space file command from the host device, the file specified by the space file piece <br/> command thus received read from the tape mark ID recording means the ID number of the data block to the tape mark (4) which, issued said read
Said tape position most the closest ID number is recorded <br/> read from the tape position ID recording section of the tape position (2), said read the same signal and the signal indicative of the tape position that issued the ID number Until the signal generation means (1) is generated
The magnetic tape is driven at high speed, and then the magnetic tape is
Drive at a low normal speed to record on the magnetic tape.
Write and read the ID number of the data block
The data is read by the output head and the read data block is read.
The ID number of the clip is the tape mark corresponding to the file.
Before when the ID number of the corresponding data block matches
Magnetic tape apparatus characterized by serial and space file command position with means you exit the positioned stops driving the magnetic tape (5), comprising a. Signal indicating the tape position wherein said tape position signal generating means (1) occurs, it is a sector signal generated on the basis of diameter values of the magnetic tape which is wound on the take-up reel The magnetic tape device according to claim 4, wherein