JPH0376057A - Floppy disk device - Google Patents

Abstract

PURPOSE:To suppress the breakdown of data to the minimum by constituting the device so that the function to write data on a recording medium, is limited to a period in which to the period in which a monostable multivibrator or a counter is kept to a high level even if a write gate signal is held to an active state. CONSTITUTION:When an ID address mark detecting signal is sent out, a monostable multivibrator 6 is triggered and sends out a pulse with prescribed width. On the other hand, the device is provided with a counter 7 for counting a prescribed value determined in advance from the time when the pulse generating means 6 is kept to an active state, and also, a data address mark detecting means 5 detects a data address mark. Also, the device is constituted so that a second write gate signal is sent out only in a period in which the pulse generating means 6 is in an active state or the counter 7 is in the course of counting, and also, a first write gate signal sent out of a floppy disk controller 2 is in an active state. In such a way, it does not occur that data written in a recording medium is updated carelessly and necessary data is brought to breakdown.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a floppy disk device, and more particularly to a write prevention circuit for a recording medium when a floppy disk control device fails.

[Conventional technology]

Conventionally, in this type of floppy disk device, if a write gate signal sent from the floppy disk controller to the floppy disk device is active, data is recorded on the recording medium. was.

[Problem to be solved by the invention]

In the conventional floppy disk device described above, if the write gate signal remains active due to a failure of the floppy disk control device, there is a risk that the data written on the recording medium may be updated inadvertently. However, the disadvantage is that necessary data is destroyed.

[Means to solve the problem]

The present invention provides a floppy disk controller that writes write data sent from a floppy disk controller to a recording medium and reads read data recorded on the recording medium.
In the disk device, ID address mark detection means for detecting an ID address mark from the read data;
pulse generating means that becomes active when the ID address mark detection means detects an ID address mark and sends out a pulse with a predetermined time width; and a data address mark that detects the data address mark from the read data. a detecting means, a counter that counts a predetermined constant value from a time when the pulse generating means is in an active state and the data/address mark detecting means detects the data/address mark, and the pulse generating means. to write data to the recording medium only during a period when the counter is in an active state or while the counter is counting and a first write gate signal sent from the floppy disk controller is in an active state. and gate signal generation means for transmitting a second write gate signal.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the floppy disk device of the present invention.

FIG. 2 is a timing chart showing the operation of FIG. 1. Further, the numbers shown in FIG. 2 correspond to the numbers shown in FIG. 1, respectively. 1 and 2, the floppy disk drive W1 of the present invention includes a first data separator 3a, a second data separator 3b, an ID address mark detection circuit 4. Data/address mark detection circuit 5° monostable multivibrator 6, first monostable multivibrator 6a, second monostable multivibrator 6b.

Counter 7, OR gate circuit 8 and AND gate circuit 9
The first data separator 3a is installed in the floppy disk device 1, and reads information written on the recording medium with a magnetic head (not shown), and generates it with a reproduction circuit (not shown). Read data 101
is inputted via a signal line, and a data discrimination signal, the so-called window signal 106, and a synchronized read data signal 105 synchronized thereto are inputted via two signal lines to the floppy disk controller 2 and the ID address mark, respectively. The signal is sent to the detection circuit 4.

Here, 100 shown in FIG. 2 is a recording format for one sector in which read data 101 is written on the recording medium, 5YNC is a synchronization field of the first data separator 3a, IDAM is an ID address mark, and IDAM is an ID address mark.
is the identifier in which the sector address is recorded,
GAP2 represents a gap, DAM represents a data/address mark, DATA represents an information recording field, and GAP3 represents a gap.

Next, the ID address mark detection circuit 4 inputs the window signal 106 and the synchronized read data signal 105, and
When the D address mark is detected, the rD address mark detection signal of positive polarity pulse is sent from the signal line 107.Then, the monostable multi-vibrator 6 is triggered by the pulse sent to the signal line 107, and a pulse of a constant width is sent out from the signal line 107. is sent to the signal line 111. On the other hand, the second data separator 3b is connected to the floppy disk controller 2.
Write data lθ2 is input through a signal line, and a data discrimination signal, a so-called window signal 109, and a synchronized write data signal 10g synchronized therewith are sent out through two signal lines. Also, data/address mark detection time 1i! ! 5 inputs a window signal 109 and a synchronized write data signal 108, and when a data address mark is detected, a positive pulse data signal is sent from a signal line 110.
Sends an address mark detection signal. Next, counter 7 is a floppy disk.

A clock signal serving as a timing reference is input from the disk controller 2 via the signal line 103, and a signal sent from the monostable multi-vibrator 6 via the signal line 111 is at a high level, and the data - When a data address mark detection signal is input from the address mark detection circuit 5 via the signal line 110, the signal M
At 112, a high level signal is sent out until a predetermined time is counted. Furthermore, the OR circuit 8 includes signal lines 111 and 112.
The AND circuit 9 receives the output signal of the OR circuit 8 and the signal line +0 from the floppy disk controller 2.
A first write gate signal is input via 4. Therefore, as shown in FIG. 2, even if the signal line 104 remains at a high level as shown by the broken line, the output from the AND circuit 9 will cause the output to the signal line 112, which is the output of the counter 7. A regulated second write gate signal is sent out via line 13. The data is then sent to a write circuit (not shown) of the floppy disk device 1.

〔Effect of the invention〕

As explained above, according to the floppy disk device of the present invention, even if the write gate signal remains active due to a failure of the floppy disk control device, data is written to the recording medium only in a monostable manner. - The period when the multi-vibrator is at high level or the period when the counter is at high level is limited, and there is an effect that data destruction on the recording medium can be minimized.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the floppy disk device of the present invention, and FIG. 2 is a timing chart showing the operation of FIG. 1. DESCRIPTION OF SYMBOLS 1... Floppy disk device, 2... Floppy disk control device, 3a... First data separator, 3b... Second data separator, 4... ID address mark detection circuit, 5...・Data/address mark detection circuit, 6... Monostable multi-vibrator, 7... Counter, 8... OR circuit, 9...
・AND circuit.

Claims (1)

[Claims] In a floppy disk device that writes write data sent from a floppy disk control device onto a recording medium and reads read data recorded on the recording medium, ID address mark detection means detects an ID address mark from the read data. and the said ID
pulse generating means that becomes active when the address mark detecting means detects an ID address mark and sends out a pulse with a predetermined time width; and data/address mark detecting means that detects the data address mark from the read data. and a counter that counts a predetermined constant value from a time when the data/address mark detecting means detects the data/address mark, and the pulse generating means is in the active state. state, or only while the counter is counting and the first write gate signal sent from the floppy disk controller is active, the first write gate signal for writing data to the recording medium is activated. 1. A floppy disk device comprising: gate signal generation means for sending out a write gate signal.