JPS6332757A - Magnetic tape device - Google Patents

Abstract

PURPOSE:To shorten an action time for rereading by counting tape running distance at the time of data block reading and rereading by setting back only counted distance to a tape. CONSTITUTION:When a magnetic tape is running in normal direction, tachopulse detection signals F go to output signals G by an AND circuit 11 and are inputted to the up count terminal of a counter circuit 14 and data in a block are read out. The final count value of the counter circuit 14 corresponds to the running distance of the tape. When data error occurs in the reading operation, an instruction for reverse running A2 is given to a control circuit 5. A capstan 7 is rotated reversely, the counter circuit 14 is counted down, and the reverse running of the tape 8 stops at the zero point. The head is placed at the position of IBG between data blocks 2 of the tape.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a magnetic tape device that reads and writes data in data blocks set on a magnetic tape.

(Prior Art) Conventionally, in a magnetic tape device, data is read from and written to a plurality of data blocks 2 set on a magnetic tape 1 as shown in FIG. Normally, the magnetic head of a magnetic tape device is positioned and stopped between two data blocks, that is, within an interblock gap (hereinafter abbreviated as IBG).

In the case of a read operation, when a running command is given, the magnetic tape 1 is driven in the direction of arrow 3, and the data in the data block 2 is read. At this time, when a data error is detected, the running of the magnetic tape 1 is temporarily stopped, and then the magnetic tape 1 is driven in the direction of the arrow 4 by a reverse running command, and the magnetic head is placed on the IBG immediately before the data block where the data error was detected. is located. Thereafter, a read operation of the same data block is performed again. In this case, if part of the magnetic tape 1 is damaged due to external factors such as storage and handling of the magnetic tape 1, the state may be insufficient to recognize data blocks on the magnetic tape during reverse running. can be,
When running in reverse, a situation occurs in which the tape passes through the corresponding data block 2 and runs further to the forward data error point. When such a situation occurs, the conventional magnetic tape device once rewinds the magnetic tape to the starting end, then runs the magnetic tape in the forward direction from the starting end, and counts the detected IBGs. Next, the magnetic tape device advances the tape to the data block or the data block next to this data block according to the count value of the IBG, and then again performs a read operation of the damaged data block or the next data block excluding the damaged data block. Performs a data block read operation. but,
After rewinding the magnetic tape to the starting edge as described above, there is a drawback that when the tape is run in the forward direction again from this starting edge, the operation takes time depending on the position of the damaged data block.

(Problems to be Solved by the Invention) As mentioned above, in the conventional magnetic tape device, when a data error occurs during data reading, the corresponding data block cannot be recognized during backward waiting, and data blocks further ahead are When running, the I6 tape is rewinded to the beginning and then the corresponding data block is searched.Therefore, it often takes time to reread the data block where a data error has occurred. SUMMARY OF THE INVENTION Therefore, the present invention aims to eliminate the above-mentioned drawbacks, and provides a magnetic tape device that can perform a re-read operation in a short time when a data block cannot be recognized when re-reading a data block on a magnetic tape. It's about doing.

[Structure of the Invention] (Means for Solving the Problems) The magnetic tape device of the present invention includes a counting means for counting the running distance of the tape when reading data from a data block on the magnetic tape, and a backward running distance of the magnetic tape ( and tape running control means for controlling the magnetic tape to return to the front of the read data block based on the running distance counted by the counting means at one o'clock.

(Function) In the magnetic tape device of the present invention, the counting means counts the distance traveled by the tape when reading a data block, and the tape running control means returns the magnetic tape by the counted distance, thereby reproducing the data. Because a read operation is performed, even if the data block to be reread cannot be recognized, the magnetic tape can be moved backwards by the distance specified above, and the magnetic tape can always be returned to the front of the data block to be reread, allowing rereading. The operation can be performed in a short time.

(Embodiment) FIG. 1 is a block diagram showing an embodiment of a tape drive control system of a magnetic tape device of the present invention.

5 is a travel control circuit that outputs a drive signal B and a drive direction signal C by inputting 1 to a travel command; 6 is a drive circuit that drives a capstan motor (not shown) that rotates a capstan 7; A capstan for running the magnetic tape 8, 8 a magnetic tape on which a data block for reversion is set, and 9 a tacho pulse for detecting the tacho pulse E generated as the capstan 7 rotates and outputting a tacho pulse detection signal F. A detection circuit, 10 is an inverter circuit that inverts the polarity of the drive direction signal C output from the travel control circuit 5, and 11.12 is an inverter circuit that inverts the polarity of the tacho pulse detection signal F. AND circuit, 1, which outputs output signals G and 1, respectively.
3 is an AND circuit that performs an AND condition on the pulse signal from the pulse generation circuit 15 and the drive direction signal @C and outputs a reset pulse L; 14 is a counting circuit that counts up or down the input signal G or l; Reference numeral 15 denotes a pulse generating circuit that outputs a pulse signal that captures the rising edge of data obtained by scanning the data block 2 with a head (not shown).

Next, the operation of this embodiment will be explained. First, when the tape running command Δ1 is given to the running control circuit 5, this circuit 5 outputs a drive signal B and a drive direction signal C to the drive circuit 6. The drive circuit 6 outputs a current to a capstan motor (not shown) based on the input signals, rotates the capstan motor in a predetermined direction, rotates the capstan 7, and runs the magnetic tape 8. capstan 7
When rotates, a tacho pulse E is generated in conjunction with this,
This tacho pulse E is detected by a tacho pulse detection circuit 9 and becomes a tacho pulse detection signal F. Tacho pulse detection signal F
is input to one input terminal of the AND circuit 11 and the AND circuit 12. The drive direction signal C is input to the other input terminal of the AND circuit 11, and the inverted signal of the drive direction signal C is input to the other input terminal of the AND circuit 12. Here, when reading data of a data block (not shown) of the magnetic tape 8, the drive direction signal C becomes high level when the magnetic tape is running in the forward direction, and when the magnetic tape is running in the reverse direction during a rereading operation, the drive direction signal C is at a high level. It is assumed that the driving direction signal C is at a low level. Therefore, when the magnetic tape is driven in the forward direction, the AND circuit 11 is opened and the tacho pulse detection signal F becomes the output signal G and is input to the up-count input terminal of the counting circuit 14. Therefore, the counting circuit 14 counts up the output signal G. In this way, the magnetic tape is run in the forward direction, and the data written in the data blocks is read out. After reading this data, the running command A1 input to the running control circuit 5
is stopped, and the output of the drive signal from the travel control circuit 5 is stopped. As a result, the drive circuit 6 enters an operation to stop the capstan motor 7, applies a reverse voltage or the like to the capstan motor 7, applies a brake, and stops the rotation of the motor. During this time, the drive direction signal C remains output from the traveling control circuit 5, so as long as the capstan 7 is rotating, the output signal G from the AND circuit 11 is input to the up-count input terminal of the counting circuit 14. Then, the counting circuit 14 continues to count up until the capstan 7 is completely stopped and the running of the magnetic tape 8 is stopped. Therefore, the final count value of counting circuit 14 corresponds to the distance traveled on the magnetic tape when reading a data block. If no data error occurs when the contents of the data block of the magnetic tape 8 are read in this way, the run command A1 is outputted to the run control circuit 5 again and the next data block is read. At this time, the pulse generating circuit 15 generates a pulse signal together with the data input start signal from the data block, and outputs the output of the AND circuit 13, which is opened by the drive signal C, to the counting circuit 14 as a reset signal. As a result, the counting circuit 14 is reset and starts counting up from O the traveling distance of the magnetic tape 8 during the next reading operation.

If a data error occurs in the above operation,
A reverse running command A2 is given to the running control circuit 5. In response to this, the travel control circuit 5 outputs the drive signal B to the drive circuit 6, and also sets the drive direction signal C, which has been output until now, to a low level. As a result, the drive circuit 6 performs an operation of driving the capstan motor in the opposite direction to that described above, causing the capstan 7 to rotate in the reverse direction and causing the magnetic tape 8 to travel in the reverse direction.

At this time, the drive direction signal AC remains at a low level, so the AND circuit 11 is closed, but the drive direction signal C is inverted by the inverter circuit 10 and becomes a high level.
Open 2. Therefore, the tacho pulse E generated when the capstan is reversed is inputted to the AND circuit 12 as the tacho pulse detection signal F by the tacho pulse detection circuit 9, and the tacho pulse detection signal F becomes the output signal H from the AND circuit 12. It is input to the down count input terminal of the counting circuit 14. Further, at this time, the AND circuit 13 is closed by the driving direction signal C, and the pulse signal from the pulse generating circuit 15 is not outputted as a reset signal.

Therefore, the counting circuit 14 counts down the backward running distance of the magnetic tape 8 from the count value corresponding to the running distance of the magnetic tape during the reading operation. In this way, the count value of the counting circuit 14 is subtracted as the magnetic tape 8 runs backwards, and when the count value reaches zero, a borrow signal J is output to the running control circuit 5. In response to this, the travel control circuit 5 stops outputting the drive signal B after a certain delay time, and the drive circuit 6
to stop the capstan motor.

As a result, the drive circuit 6 applies a reverse voltage or the like to the capstan motor to apply a brake to stop the capstan motor, thereby stopping the magnetic tape 8 from running.

In this case, the magnetic tape 8 travels in reverse for the distance traveled during data reading, so if the head is located at the IBG between the data blocks at the start of data reading,
At the end of the reverse run 11, the magnetic tape 8 can be returned so that the head is located in the IBG placed immediately before the data block in which the data error occurred.

According to this embodiment, regardless of whether a data block is recognized or not, if a data error occurs during reading, the magnetic tape 8 is reversed and stopped by the distance traveled by the magnetic tape when reading data, so a rereading operation is performed. The reversal of the tape at the time of reading can be minimized, and the processing time for rereading can be shortened.

[Effects of the Invention] As described above, according to the magnetic tape device of the present invention, the running distance of the magnetic tape when reading data is counted, and when the magnetic tape is reversed, the magnetic tape is moved by the counted running distance. By reversing and stopping, there is an effect that when rereading a data block on the magnetic tape, the rereading operation can always be performed in a short time regardless of whether or not the relevant data block is recognized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the magnetic tape device of the present invention, and FIG. 2 is a diagram showing an example of the arrangement of data blocks installed on the magnetic tape. 5... Traveling control circuit 6... Drive circuit 9... Tacho pulse detection circuit 10... Inverter circuit 11.12.13... AND circuit 14... Counting circuit 15... Pulse generation circuit substitute Patent Attorney Nori Chika Ken Shu Kanshu Sanno −

Claims (1)

[Claims] In a magnetic tape device that reads and writes data to a plurality of data blocks arranged on a magnetic tape, there is provided a counting means for counting the traveling distance of the tape when reading data from a data block on the magnetic tape, and a counting means for counting the traveling distance of the tape when the data is being read from a data block on the magnetic tape, and when the magnetic tape is traveling in reverse. A magnetic tape device comprising: tape running control means for controlling the magnetic tape to return to the front of the read data block based on the running distance counted by the counting means.