Peripheral Technology Inc.

Computer Memories, Incorporated

Donald G Stupeck

Ara W Nazarian

Gaston A Palombo

Hugh K Gagnier

An automatic head retract system for a disk drive. The system operates in response to electric power turn off to retract the heads to a landing zone on the disk surface. The heads are retracted by operating a positioner motor under the control of logic internal to the disk drive unit without intervention by a host computer. The positioner motor comprises a multiphase DC brushless motor which, after power loss, is supplied with current from a capacitor charged during normal drive usage, and by the back EMF of a spindle motor. A latch mechanically locks the heads in the landing zone.

Automatic head retract system for disk drive

An automatic head retract system for a disk drive is disclosed which operates in response to electric power turn off to retract the heads to a landing zone on the disk surface. The heads are retracted by operating a positioner motor under the control of logic internal to the disk drive unit without intervention by a host computer. The positioner motor comprises a multiphase DC brushless motor which, after power loss, is supplied with current from a capacitor charged during normal drive usage and by the back EMF of a spindle motor. A latch mechanically locks the heads in the landing zone.

A low cost disk drive system includes track zero information located in a single sector on the disk surface. The information is comprised of a first type of signal located in tracks to one side of an arbitrary reference track and a second type of signal located in the tracks to the other side of the arbitrary reference track. The magnetic head of the disk drive system is moved radially with respect to the disk and the transition between the signals detected in order to locate the head at the reference track.

Disk drive with track zero location system

Disclosed is a rotational speed control system for comparing the rotational speed of a rotating disk as indicated by index pulses occurring one or more times per revolution of the disk, with a reference time representing the desired time between successive index pulses. The system employs logic circuitry external to any microprocessor control system employed by the rotating disk system. The reference time may be supplied by counters counting externally supplied clock pulses to a fixed value. The speed control system provides a speed up command or slow down command in a manner proportional to the speed error to the disk drive motor where the time between successive index pulses is greater or less, respectively, than the reference time.

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Canoga Park, CA, United States of America

Donald G Stupeck