JPS5842532B2 - Magnetic tape control method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a magnetic tape control system.

Position indicators indicating the start and end of the magnetic tape (BOT marker at the start and EOT marker at the end) are pasted on the magnetic tape.

This marker is made of aluminum foil or the like that can be detected by reflecting light.

When the BOT marker is detected while the magnetic tape is running in reverse, the magnetic tape is stopped and then run in the forward direction for recording and reproduction.

Recording is performed between the BOT marker and the EOT marker.

By the way, with magnetic tape, the magnetic layer can peel off, and the peeled off area becomes a BOT marker or EOT marker due to reflection.
The marker may be mistakenly detected as the same type of marker.

For example, if a marker of the same type as a BOT marker is detected, recording and reproducing between the BOT marker and the position where the magnetic layer has peeled off may become impossible, and if a marker of the same type as an EOT marker is detected, the magnetic layer may peel off in the same way. Recording and reproducing between the position and the EOT marker becomes impossible.

Referring to FIG. 1, a BOT marker 12 is pasted on a magnetic tape 11, and peeling 13 of the magnetic layer is a BOT marker.
This occurs so that it can be detected as a T marker.

First, as shown by A, the BOT marker 12 is detected during reverse running and the tape is stopped, and then recording is performed during forward running as shown by B.

Since there is no need to detect the BOT marker during forward operation, the detection of peeling 13 is ignored.

When the recording is finished and an attempt is made to return to the BOT marker position by reverse running operation as shown by C, the peeling 13 is detected as a BOT marker and it stops at the position of the peeling 13.

Therefore, it becomes impossible to reproduce the information within the range.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a magnetic tape control system that solves the above-mentioned problems.

FIG. 2 shows an embodiment of the invention, the alphabetical symbols of which correspond to the signals indicated by the alphabetical symbols of FIG.

A start end display signal (BOT marker detection signal) a applied to line 21 is applied directly to AND gate 25 and also applied to AND gate 25 via delay circuit 23 and inverter circuit 24 .

AND gate 25 is further provided with a forward running signal via line 22.

Therefore, the signal C from the AND gate 25 is the BOT marker (
(includes peeling etc. similar to the BOT marker).

Signal C is applied to the trigger terminal of flip-flop 26.

The flip-flop 26 is reset by a clear signal applied to the initial line 27, and is set by the signal C.

The set output signal d and the start end display signal a are connected to the AND gate 28.
Therefore, in addition to BOT marker 12, BO
When the same type of peeling as the T marker is detected (this means that the BOT marker has been detected twice), an error signal e is output to the line 29.

In addition to the method described above, various means for detecting the existence of the same kind of indicator twice or more can be considered.

As described above, according to the present invention, it is possible to eliminate the non-renewable state.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining a conventional example, FIG. 2 is a diagram showing an embodiment of the present invention, and FIG. 3 is a diagram showing waveforms of various parts in FIG. 11...magnetic tape, 12...BOT
Marker, 13...Peeling of magnetic layer, 23...
...Delay circuit, 24...Inverter circuit, 2
6...Flip-flop.

Claims (1)

[Claims] 1. In a magnetic tape device in which different types of position indicators are provided at the beginning and end of a magnetic tape, and a temporary stop control is performed when one of the above position indicators is detected while the magnetic tape is running, the same type of position indicators in the same running direction may be used. A magnetic tape control system characterized in that an error message is displayed when an indicator is detected twice or more.