JPH02128306A - Magnetic tape controller - Google Patents

Abstract

PURPOSE:To surely check a data by read-out operation after write operation by resetting plural prescribed stages before the last stage of a system register, when an interblock gap in the rear of a data block is detected. CONSTITUTION:Data recorded in a magnetic tape 1 is read out by a reproducing head 3, amplified by a reproducing circuit 5 and executes a prescribed processing of a peak detection, etc. An interblock gap (IBG) detecting circuit 6 detects a data block, a tape mark and an IBG from an output signal of the reproducing circuit 5. A shift register 7 is a shift register of 11 stages, inputs and records a write end signal 10 from a write circuit 4, constituted so as to reset its 8-th, 9-th and 10-th stages by an IBG detecting signal from the IBG detecting circuit 6, and an output signal of the last stage (11-th stage) goes to an error detecting signal. In such a way, after a write operation, a check by a read-out operation can be executed surely.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic tape control device for controlling the operation of a magnetic tape device for information exchange, and in particular a read operation for error detection after a write operation. The present invention relates to a control device for a magnetic tape device.

[Conventional technology]

When recording data on a magnetic tape, a conventional magnetic tape device control device performs a read operation (first-after-write check) to detect errors after a write operation.
Within a certain period of time after the start or end of writing of one data block (block), the interblock gap (IB
An operation is performed to confirm that G> is detected.

[Problem to be solved by the invention]

The read-after-write check means in the conventional magnetic tape device described above reads the information in the block written by the write head by the playback head disposed adjacent to the write head, and This method determines an error if an IBG existing at the beginning or the rear of the block cannot be detected within a time corresponding to the read/write gap (referred to as a read/write gap) plus an appropriate tolerance.

However, if the read/write gap is larger than the length of the IBG, it is necessary to start writing the next block before the read-after-write check operation for one block is completed. However, there is a drawback that the conventional methods described above cannot be applied.

[Means to solve the problem]

A magnetic tape control device of the present invention includes a write circuit for recording data on a magnetic tape, a reproduction circuit for reading data recorded on the magnetic tape, and a reproduction signal from the reproduction circuit. IBG that inputs and detects data blocks, tape marks, and interblock gaps
A detection circuit and a multi-stage system register circuit that takes into account the time corresponding to the interval between the write head and the playback head plus an appropriate tolerance, and when the write operation of one data block is completed. A signal is input to the shift register to record the information, and when an interblock gap at the rear of the data block is detected, a predetermined plurality of stages before the final stage of the system register are reset. It is something.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.

In FIG. 1, 1 is a magnetic tape, 2 is a writing head,
3 is a playback head, 4 is a write circuit, and 5 is a playback circuit. When recording data on the magnetic tape 1, the magnetic tape 1 is run at a constant speed in the direction of arrow A, and the write circuit 4
By passing the recording current generated in the write head 2 through the write head 2, the magnetization of the magnetic tape 1 is reversed and data is recorded. The data recorded on the magnetic tape 1 is read out by the playback head 3, amplified by the playback circuit 5, and subjected to predetermined processing such as peak detection. This is a circuit that detects marks and IBGs. The shift register 7 is an 11-stage shift register, and the write end signal from the write circuit 4 <W
END) 10 is input and recorded, and the 8th, 9th, and 10th stages are reset by the IBG detection signal (REND) from the IBG detection circuit 6, and the final stage (END) is input and recorded.
The output signal of the 11th stage) is the error detection signal (ERROR).
It becomes.

Next, the operation of this embodiment will be explained with reference to FIG.

FIG. 2 is an explanatory diagram showing the relationship between the movement of the magnetic tape and the state of the shift register.

In FIG. 2, W indicates the position of the write head 2, R indicates the position of the read head 3, and 11, 12, and 13 indicate blocks recorded on the magnetic tape 1. Now, set the read/write gap to 3.
8 mm, IBG length 21, magnetic tape running speed 2 m/s, shift register 7 shift clock period 0.
．． It will be 25m5.

FIG. 2(a) shows the state of block 11 at the end of writing. Here, information °゛1 is placed in the first stage of the shift register 7.
” will be loaded.

FIG. 2(b) shows the state of block 12 at the end of writing. Here, information "1" is loaded again into the first stage of the shift register. The information "1" loaded at the end of writing of block 1 has been moved to the seventh stage of the shift register.

FIG. 2(c) shows a state in which the block 11 has finished passing under the reproducing head 3 and the IBG 21 behind the block 11 has been detected. At this time, the IBG detection time fi'86 is R
An END signal 9 is generated to reset the 8th, 9th, and 10th stages of the shift register. At this time, block 11
Information I input to the shift register at the end of writing
I II I+ is in the ninth stage of the shift register and is therefore reset and does not appear on the output side of the shift register.

FIG. 2(d) shows the state when an error is detected. Block 1
If the IBG 2 or the rear IBG of block 12 cannot be detected correctly, the information ``''1'' input to the shift register at the end of writing of block 12 will be the 8 of the shift register.
Since the REND signal is not generated at the 9th and 10th stages, it appears at the final stage (11th stage) of the shift register without being reset. By outputting this as an error signal 8, an abnormality in the block 12 can be detected.

〔Effect of the invention〕

As explained above, the magnetic tape control device of the present invention includes:
In a recording system in which the interval between the write head and the read head is larger than the length of the IBG, there is an effect that a check can be reliably performed by the read operation after the write operation.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is an explanatory diagram showing the relationship between the movement of the magnetic tape and the state of the shift register in the embodiment of FIG. 1...Magnetic tape, 2...Writing head, 3...
reproducing head, 4... writing circuit, 5... reproducing circuit,
6... G detection circuit, 7... shift register, 1
1, 12, 13...Block (on magnetic tape), 2
1...IBG.

Claims (1)

[Claims] a write circuit for recording data on magnetic tape;
a reproduction circuit for reading data recorded on the magnetic tape; an IBG detection circuit for receiving a reproduction signal from the reproduction circuit to detect data blocks, tape marks, and interblock gaps; and a write head. and a multi-stage system register circuit that takes into account the time corresponding to the interval between the playback head and the playback head, with an appropriate tolerance added, and sends a signal to the shift register when the writing operation of one data block is completed. The magnetic register is configured to input and record the information, and to reset a predetermined plurality of stages before the final stage of the system register when an interblock gap at the rear of the data block is detected. Tape controller.