The present invention relates to the driving of a floppy disk and, more particularly, to the driving of a tunnel erase type floppy disk.
A conventional tunnel erase type floppy disk comprises a read/write (R/W) head and a pair of erasing heads positioned to the rear of the read/write head. The pair of erasing heads are operated for erasing both sides of data recorded by the read/write head, so that a non-data record area is provided between the tracks to assure compatibility.
Normally, because the record tracks are arranged to be coaxial, the outer portions of the record disk move more slowly than the inner portions of the disk. Each of the tracks contain an identification (ID) field for storing address information, a data field for storing data, and a gap. If while recording data into the floppy disk the read/write head and the pair of erasing heads are simultaneously operated and the track is improperly aligned, the pair of erasing heads may erroneously erase the data in the ID field, and may not conduct a tunnel erasure of the data field. Therefore, conventionally, the pair of erasing heads are operated as being delayed at a predetermined time after the read/write head is energized.
Because the outer tracks of the disk move more slowly than the inner tracks of the disk, a common predetermined delay time is not suitable for all the tracks.
Due to the usage of a common delay time, it may be difficult to delay the ON condition of each of the pair of erase heads at a satisfactory time with respect to all of the tracks.