Quantum Corporation

Digital Equipment Corporation

William F Even

William D Lewis

A disk drive in a multi-disk storage system has a spindle synchronizer and a spindle controller that are microprocessor-based. The spindle synchronizer has a counter used to track the phase of a master phase reference signal that is distributed to all the disk drives in the storage system. The counter may also optionally be used to generate the master reference signal. The spindle synchronizer also has programmable registers and a comparator that are used to generate a spindle reference signal having a programmable phase offset relative to the master reference signal, and a register used to sample the phase of the master reference once per revolution of its associated spindle. The spindle controller contains a counter used to measure the actual rotational period of the associated spindle. The spindle phase error is used in a phase correction algorithm that controls a reference voltage supplied to a motor spin controller. The algorithm employs frequency switching to phase-lock the associated spindle with the spindle reference signal generated by the spindle synchronizer.

Phase locking a disk drive spindle to a reference signal

Synchronization of multiple disk drive spindles

A data storage system having a number of disk drives is disclosed. Each disk drive is provided with a disk spindle driven by a spindle motor. The disk spindle is utilized for mounting one or more disks whose surface is used for data storage. A read/write head mounted on an actuator is provided for each disk surface. Each read/write head is positioned over a desired location on the disk surface by a control mechanism in order to transfer data to and from the disk surface. Data and position information are encoded on each disk surface according to a pre-specified format. The rotation of the disk spindle is controlled to maintain a desired angular position and velocity. A sensor signal indicative of the disk spindle angular position and velocity is obtained independently of the position information encoded on the disk surface. A reference signal, which is obtained from the disk surface, is combined with the sensor signal to adjust the angular position of the disk spindle.

Growing community of inventors

Auburn, MA, United States of America

William F Even