JPH04168610A - Magnetic tape device - Google Patents

Abstract

PURPOSE:To simplify control from a magnetic tape controller by providing a timer counter for counting a timer until a driver detects a medium error. CONSTITUTION:A timer counter 4 for counting a timer until a demodulator 3 detects a medium error in data writing, and a controller 8 for controlling an erasing circuit 1, a writer 2, the demodulator 3, the counter 4, a data buffer 5, and a driver 7, etc., are provided. It is erased to a position in which a predetermined distance is added to a medium error position, based on the output of the counter 4 and a medium error signal of the demodulator 3 in the erasing operation continued to a space reversing operation after writing, and then data is rewritten in the buffer 5. Thus, if a drop bit of the medium error is generated in the writing operation, the error is automatically avoided by one automatic retrial process, thereby simplifying the control of a magnetic tape device.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic tape device that is an external storage device for an information processing device.

[Prior Art] A conventional magnetic tape device of this type has a block configuration as shown in FIG. 2, and has a recording state as shown in FIG. 4.

The magnetic tape control device 20 sends write data together with a write command to write data to the magnetic tape device 11A.

The magnetic tape device 11A receives a write command from the magnetic tape control device through the interface circuit 6 and starts a write operation.

Interface circuit 6 sends a write command to control circuit 8A. The control circuit 8A controls the drive circuit 7 to control the reel motors 9 av 9 b and the capstan motor 10.
is driven to run the magnetic tape medium 12 in the traveling direction. Furthermore, at the beginning of a write operation, a write error flag in an internal register (not shown) of the control circuit 8A is reset. While data previously written on the magnetic tape medium is erased by the erasing head 1a in the erasing circuit 1 under the control of the control circuit 8A, new data from the interface circuit 6 is erased from the writing circuit 2 under the control of the control circuit 8A. Writing is performed on the magnetic tape medium using the write head 2a. At this time, in order to confirm the write state, new data written to the magnetic tape medium is sent to the read head 3a in the demodulation circuit 3.
The data is read out, the analog signal waveform is shaped into a pulse signal waveform, the data is demodulated, and the data is output to the interface circuit 6 under the control of the control circuit 8 . Furthermore, demodulation circuit 3
The system determines whether the level of the analog data read signal read from the magnetic tape medium is above a certain level, and when the level of the data read signal is below a certain level, a dropout bit (hereinafter referred to as a drop bit) is used. ) and outputs a medium error signal to the control circuit 8A.

Prior to this, when the control circuit 8A receives a medium error signal from the demodulation circuit 3, it sets a write error flag in an internal register (not shown), and when data writing is completed, the control circuit 8A sends the medium to the magnetic tape control device via the interface circuit 6. Report that there was an error.

In this way, data is written from point a to point aa, including the medium error position point p, as shown in FIG. 4(a).

When the magnetic tape control device receives a report of a medium error, it performs the following retry process to avoid the medium error.

The magnetic tape control device sends a space reverse command to the magnetic tape device 11A.

The magnetic tape device 11A receives a space reverse command from the magnetic tape control device through the interface circuit 6 and starts a space reverse operation.

The interface circuit 6 outputs the received command to the control circuit 8A. The control circuit 8A controls the drive circuit 7 and drives the reel motor 9a s 9 b and the capstan motor 10 to run the magnetic tape medium in the opposite direction.

The demodulation circuit 3 detects the start of writing data written on the magnetic tape medium and outputs it to the control circuit 8A.

Therefore, the control circuit 8A controls the drive circuit 7 to stop driving the motor.

In this way, the magnetic tape medium is made to run backwards from point aa to point a.

Next, the magnetic tape control device sends an erase command to the magnetic tape device 11A.

The magnetic tape device 11A receives an erase command from the magnetic tape control device through the interface circuit 6 and starts an erase operation. The interface circuit 6 outputs the received command to the control circuit 8A. The control circuit 8A controls the drive circuit 7 to drive the reel motors 9a + 9b and the capstan motor 10 to run the magnetic tape medium in the traveling direction, and controls the erasing circuit 1 to erase a predetermined distance. .

The magnetic tape medium is now as shown in Figure 4(b).
The points from point a to point b are erased.

Next, the magnetic tape control device resends the same data in which the medium error occurred to the magnetic tape device 11A together with a write command.

The magnetic tape device 11A receives the same data in which the medium error has occurred together with a write command from the magnetic tape control device again, and executes the same write operation as described above.

Now the magnetic tape medium has b as shown in Figure 4(b).
Although data is written from point bb to point bb, the medium error position point p is also included in FIG. 4(b) because it is at the same position as in FIG. 4(a). Furthermore, due to the above operation, the fourth
As can be seen from Figure (b), the data previously written on the magnetic tape medium has been shifted by the distance erased in the backward direction.

Even in the write command retry processing following the erase command after the space reverse command of the magnetic tape control device, if a medium error report is still received from the magnetic tape device 11A, the above series of retry processing is repeated, and the position where no medium error is detected is reached. The data is shifted and written until the end.

In this way, data is written onto the magnetic tape medium while being shifted from point n, which does not include the nine medium error positions, to point nn, as shown in FIG. 4(C).

[Problems to be Solved by the Invention] The conventional magnetic tape device described above executes a series of retry processing based on instructions from the magnetic tape control device, so the control from the magnetic tape control device is complicated. Another drawback is that it takes a lot of time to lock up the magnetic tape control device.

[Means for Solving the Problems] A magnetic tape device of the present invention includes: a reel motor and a capstan motor that run a magnetic tape medium; a write circuit that writes data to the magnetic tape medium; and a write circuit that writes data to the magnetic tape medium. an erasure circuit that erases data written on the magnetic tape medium; a demodulation circuit that reads and demodulates data written on the magnetic tape medium and detects the occurrence of drop bits due to medium errors; and a demodulation circuit that drives the reel motor and the capstan motor. a timer counter for counting the time until the drive circuit detects a medium error; a data buffer for storing data to be written on the magnetic tape medium; It is characterized by comprising a control circuit that erases data up to a position where a certain distance is added to the medium error position based on the output of the timer counter and the medium error signal of the demodulation circuit, and then rewrites the data in the data buffer. do.

[Example code] Next, the present invention will be explained with reference to the drawings.

Fig. 1 is a block diagram of one embodiment of the present invention, and Fig. 3 is a block diagram of an embodiment of the present invention.
FIG. 4 is an explanatory diagram of a recording state according to the illustrated embodiment.

As shown in FIG. 1, a magnetic tape device 11 of this embodiment
B is connected to the magnetic tape control device 2o, and includes an interface circuit 6 that exchanges data signals and control signals with the magnetic tape control device, a data buffer 5 that stores write data, and a magnetic tape medium 12 that runs on the magnetic tape medium 12. reel motor 9a19b and capstan motor 1o
, a drive circuit 7 that drives the reel motors 9 a and 9 b and the capstan motor 10 , an erase circuit 1 that has an erase head and erases data written on a magnetic tape medium, and a write head. a write circuit 2 that writes data to a magnetic tape medium; a demodulation circuit 3 that has a continuous head that reads and demodulates data from the magnetic tape medium and detects drop bits due to medium errors; A timer counter 4 that counts the time until an error is detected, and an erase circuit 1. Write circuit 2. Demodulation circuit 3. Timer counter 4. Data buffer 5. A control circuit 8B that controls the drive circuit 7 is provided.

Next, the operation of this embodiment will be explained.

In FIG. 1, first, the magnetic tape control device 20 sends write data together with a write command in order to write data to the magnetic tape device 11B.

The magnetic tape device 11B receives a command from the magnetic tape control device through the interface circuit 6 and starts writing. The interface circuit 6 transfers the received command to the control circuit 8B.
and write data to data buffer 5.
The data buffer 5 stores the write data. The control circuit 8B controls the drive circuit 7 to drive the reel motor 9a.

9b and the capstan motor 10 are driven to run the magnetic tape medium in the traveling direction. Furthermore, at the beginning of the write operation, the write error flag, data buffer 5, and timer counter 4 of an internal register (not shown) of the control circuit 8B are reset. While the data already written on the magnetic tape medium is erased by the erase head of the erase circuit 1 under the control of the control circuit 8B, the data from the data buffer 5 is sent to the write head of the write circuit 2 under the control of the control circuit 8B. and write it onto a magnetic tape medium.

At this time, immediately afterward, in order to check the writing status, the new data written to the magnetic tape medium is read out by the successive head of the demodulation circuit 3, the analog signal waveform is shaped into a pulsed signal waveform, and the data is demodulated. It is output to the interface circuit 6 under the control of the control circuit 8B. Furthermore, the demodulation circuit 3 determines whether the level of the successive signal of analog data read from the magnetic tape medium is above a certain level, and when the level of the data read signal is below a certain level, it is regarded as a drop bit. Media error signal control circuit 8B
and output to timer counter 4.

The timer counter 4 counts the time until the medium error signal of the demodulation circuit 3 is output in the write operation, and outputs counting information to the control circuit 8B.

When the control circuit 8B receives the medium error signal from the demodulation circuit 3, it sets a write error flag in an internal register (not shown), and when the data write is completed, it sends a message to the magnetic tape control device via the interface circuit 6 indicating that a write error has occurred. Report the matter.

The timer counter 4 outputs time counting information from point a of the magnetic tape medium to point 9 of the medium error position shown in FIG. 3(a) to the control circuit 8B.

Now, as shown in FIG. 3(a), data is written from point a to point aa including nine medium error positions.

When the write error flag is set in an internal register (not shown), the control circuit 8B performs the following series of automatic retry processes of space reverse operation, erase operation, and write operation to avoid medium errors.

First, for space reverse operation, the control circuit 8B controls the drive circuit 7 to drive the reel motor 9a.

9b and the capstan motor 10 are driven to run the magnetic tape medium in the opposite direction. The demodulation circuit 3 detects the start of writing data written on the magnetic tape medium and outputs it to the control circuit 8B. In response to this, the control circuit 8B controls the drive circuit 7 to drive the reel motors 9 a r 9 b.
And the driving of the capstan motor 10 is stopped.

In this way, the magnetic tape medium is made to run backwards from point aa to point a.

The control circuit 8B controls the drive circuit 7 for the subsequent erase operation.
The reel motor 9a * 9b and the capstan motor 10 are driven to run the magnetic tape medium in the advancing direction, and the time count information of the timer counter 4 is read by setting the medium error flag of an internal register (not shown). Based on this, as shown in FIG. 3(b), the erasing circuit 1 is controlled to erase from point a to point r, which is the distance from point a to point 11p, which is the medium error point, plus a certain distance.

In this way, the old data on the magnetic tape medium includes nine medium error positions and is erased from point a to point r.

In a subsequent write operation, the same data in which a medium error has occurred, which is stored in the data buffer 5, is written to the magnetic tape medium in the same write operation as described above.

As a result, as shown in FIG. 3(b), data is written on the magnetic tape medium from point r to point rr, which is the nine medium error positions plus a certain distance.

Therefore, the rewritten data does not include the nine medium error positions.

[Effects of the Invention] As explained above, the present invention enables the control of the magnetic tape device to be improved by automatically avoiding the medium error with a single automatic retry process when a drop bit due to a medium error occurs during a write operation. It produces an effect that can be easily achieved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a block diagram of a conventional example, FIG. 3 is an explanatory diagram showing the state of recording on a magnetic tape medium according to the embodiment of FIG. 1, and FIG. FIG. 3 is an explanatory diagram showing a state of recording on a magnetic tape medium according to the conventional example of FIG. 2; DESCRIPTION OF SYMBOLS 1... Erase circuit, 2... Write circuit, 3... Demodulation circuit, 4... Timer counter, 5... Data buffer, 6... Interface circuit, 7... Drive circuit,
8A. 8B...Control circuit, 9a+ 9b...Reel motor, 10...Capstan motor, IIA, IIB・
・Magnetic tape device, at b+ ns r...
Data writing start point, p--media error position, aa, b
bt nn*rr... Data writing end point.

Claims (1)

[Scope of Claims] A reel motor and a capstan motor that run a magnetic tape medium, a write circuit that writes data to the magnetic tape medium, and an erase circuit that erases data written to the magnetic tape medium. a demodulation circuit that reads and demodulates data written on the magnetic tape medium and detects the occurrence of drop bits due to a medium error; a drive circuit that drives the reel motor and the capstan motor; and a drive circuit that drives the reel motor and the capstan motor; a timer counter that counts time until a magnetic tape medium is detected; a data buffer that stores data to be written on a magnetic tape medium; and a data buffer that stores data to be written on a magnetic tape medium; and a data buffer that stores data to be written on a magnetic tape medium; 1. A magnetic tape device comprising: a control circuit for erasing data up to a position that is a predetermined distance from a medium error position based on the above, and then rewriting data in the data buffer.