System for holding a track counter active despite power suspension in rotating disk data storage apparatus

摘要

A floppy disk drive is disclosed which is for use with a host system capable of connecting its own power supply to the disk drive when its operation is needed, and disconnecting the power supply from the disk drive when its operation is not needed. The disk drive includes a stepper motor for moving a data transducer from track to track on a rotating magnetic disk, and a track counter for ascertaining the radial position of the transducer on the disk by counting the stepping pulses fed from the host system to a stepper motor control circuit. In order to maintain the count of the track counter despite power suspension, the track counter is connected to a supply terminal of the disk drive via a reverse blocking diode, and a capacitor is connected between the diode and ground. The track counter is therefore fed from the capacitor when the disk drive is disconnected from the power supply of the host system. Preferably, the count of the track counter when the disk drive is disconnected from the power supply may be temporarily stored on an electrically erasable, programmable read only memory, and the stored count may be returned to and preset on the track counter when the disk drive is subsequently powered on.