| 摘要 |
A flexible magnetic disk drive has an index sensor which, during the rotation of the magnetic disk, generates a series of index pulses representative of the angular position of the magnetic disk. The index pulses are delivered to a host system only when a drive select signal supplied therefrom to the disk drive is in a prescribed state dictating the execution of reading or writing by that disk drive. Since the host system responds to the leading edges of the incoming index pulses for formatting the magnetic disk, any index pulse should be suppressed if the drive select signal assumes the prescribed state during the duration of that index pulse; otherwise, the leading edge of the index pulse would erroneously represents the angular position of the magnetic disk. Thus the disk drive circuitry is improved, typically by incorporating a flip-flop circuit, for suppressing the undesired index pulse and for permitting the delivery of the subsequently generated index pulses as long as the drive select signal remains in the prescribed state.
|
