JPH03157805A - Flexible disk device - Google Patents

Abstract

PURPOSE:To prevent information overwritten with a low track density from being left unerased by inputting the output of a delay circuit, a side select signal sent from a host, and a track density selecting signal and turning on a side erase head selected by the side select signal only at the time when the track density selecting signal indicates the low density. CONSTITUTION:When the track density selecting signal is in the low level, the low-track density state is set; and when information is overwritten on a medium of low track density in this state, a write gate signal passes a delay circuit 1 and is delayed to become an erase gate signal. When the side select signal is in the high level, a side erase head 3 on the side 0 is turned on; and when the side select signal is in the low level, a side erase head 4 on the side 1 is turned on. Thus, a failure of erasing is prevented though the track center position of the low-track density medium on which information is overwritten is deviated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a flexible disk device, and more particularly to a high track density flexible disk device that does not perform site erase.

[Conventional technology]

Conventionally, flexible disk devices have not had a side erase head or a side erase head circuit.

[Problem to be solved by the invention]

Since the above-described conventional flexible disk device does not perform site erase, it has the disadvantage that unerased areas are left when overwriting a medium written on a low track density device.

[Means to solve the problem]

The flexible disk device of the present invention includes a delay circuit connected to a write gate signal sent from a host, and inputs the output of the delay circuit, a side select signal and a track density selection signal sent from the host, and selects a track density switching signal when the track density switching signal is low. The device includes a logic circuit that turns on a side erase head selected by a side select signal only in the case of density, and a side erase head connected to the logic circuit.

〔Example〕

FIG. 1 is a circuit diagram of an embodiment of the present invention. Also, the third
FIG. 4 is a head layout diagram of an embodiment of the present invention, FIG. 4 is a head layout diagram of a conventional example, and FIG. 5 is a head layout diagram of a low track density device. The read/write head of the present invention is in the same position as the prior art, and the total width of the two side erase heads and the read/write head is the same as in FIG. 5 for a low track density device.

FIG. 2 is a time chart showing the operation of the above flexible disk device. In the figure, when the track density selection signal is at L level, the flexible disk device is in a low track density state. When overwriting a low track density medium in this state, the write gate signal passes through the delay circuit 1 and is delayed to become an erase gate signal. When the side select signal is at H level, side 0
The side erase head 3 on the side is turned on. When the side select signal is L, side erase head 4 on side 1 side
turns on. Even if the track center position of the low track density medium to be overwritten is shifted, there will be no unerased areas as shown in FIG. Therefore, the overwritten medium is
As shown in the figure, it is possible to read even low track density equipment.

When the track density selection signal is at H level, site erase is not performed as in the conventional case, and the track density is high as shown in FIG.

〔Effect of the invention〕

As explained above, according to the present invention, a high track density device that does not perform site erase is compatible with a low track density device.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an embodiment of the present invention, Fig. 2 is a time chart showing the operation, Fig. 3 is a head arrangement diagram, Fig. 4 is a head arrangement diagram of a conventional example, and Fig. 5 is a low track. The head arrangement diagrams of the density device, FIGS. 6 to 8 are explanatory diagrams showing examples of operations. 1...Delay circuit, 2...Logic circuit, 3.4...Side erase head. 3 tsubo Figure 45-

Claims (1)

[Claims] A delay circuit is connected to a write gate signal sent from the host, and the output of the delay circuit, a side select signal and a track density selection signal sent from the host are input, and the track density switching signal is selected by the side select signal only when the density is low. A flexible disk device comprising: a logic circuit that turns on a side erase head that has been erased; and a side erase head that is connected to the logic circuit.