Quantum Corporation

David B Jeppson

Donald C Westwood

Eric J Botto

Richard J Blackborow

Scott E Richmond

Claude E Camp

Peter S Hahn

Rodica Florea

Richard M Ehrlich

Gary W Calfee

William N Thanos

Bryan John Mee

Norman H Wulferdinger

Joseph C Liu

Benjamin M Miller

A disk drive assembly including circuitry for adaptively selecting performance characteristics of the assembly. The performance characteristics are adaptively selected responsive to a balancing of maximizing performance of the assembly while also minimizing occurrences of misoperation. A disk drive assembly of improved characteristics and error correcting capabilities is provided.

Adaptively-controlled disk drive assembly

A disk drive having: (a) at least one data disk; (b) a brushless DC motor coupled to the data disk, the motor having: (i) multiple phase windings arranged as a stator, and (ii) a rotor having a permanent magnet or a DC current excitation winding for rotating the data disk; (c) a transducer for writing data to or reading data from the data disk; (d) a carrier supporting the transducer; (e) a voice coil motor coupled to the carrier for moving the carrier radially across the disk; (f) a drive controller coupled to the brushless DC motor and to the voice coil motor; and (g) a support for supporting the brushless DC motor, the voice coil motor and the drive controller. The drive controller periodically samples the rotor position and then drives the motor by energizing appropriate phase windings in relation to the rotor position that provide maximum forward torque to the rotor. While driving the motor, the drive controller also applies a series of current pulses to the VCM to oscillate the head carrier radially in and out. The combined application of maximum torque to the rotor and oscillation of the head carrier overcomes stiction between the slider and the surface of the disk to rotate the disk.

Disk drive with closed loop commutator and actuator oscillator

A hard disk drive spindle synchronization method comprises the steps of: sending an index marker pulse generated within each disk drive to mark in time a beginning of each rotation of the disk spindle thereof to a party line to which all drives are connected, rotating the disk spindle at a slightly different rotational velocity than any other drive of the array, monitoring drive pulses present on the spindle reference party line from other disk drives of the plurality to locate a center of gravity of pulse clusters which is within approximately plus or minus one quarter revolution of the drive's own index marker pulse, upon detection of a said center of gravity, ceasing to rotate the disk spindle at a slightly different rotational velocity during a second phase, adjusting the rotational phase of each drive to converge toward the center of gravity until all drive pulses present on the spindle reference party line converge into a single composite marker pulse present on the spindle reference party line, and maintaining convergence of the drive pulses during continuing operations of the disk drives by monitoring the spindle reference party line and making slight phase adjustments of the rotational phase of each drive, thereby phase locking all of the disk spindles of the plurality of hard disk drives to a single composite index marker signal present on the party line.

Masterless synchronized spindle control for hard disk drives

A digital servo control loop for a disk drive head position actuator implements a multi-rate notch filter in order to eliminate actuator resonances at frequencies above the sampling rate Nyquist frequency. The control loop includes circuitry responsive to the periodic digital position values sampled from embedded servo sectors which generates and puts out digital control values at the predetermined sampling rate for controlling the position of the actuator means. A digital multi-rate notch filter receives and filters the digital control values, and generates and puts out notch filtered digital control values to the actuator means at a rate comprising an integral multiple of the predetermined sampling rate.

Digital multi-rate notch filter for sampled servo digital control system

A method is provided for allocating digital processing activities of an embedded microcontroller within a disk drive between repetitive periodic digital servo loop service routines synchronized to rotation of a data storage disk of the drive and irregularly occurring host service routines supporting a high level, digital interface to a host computing environment. The new method comprises the steps of:

Servo pause for disk drive embedded multi-tasked controller

A removable and transportable hard disk subsystem is provided for use with at least one computer and includes at least one hard disk module. The module contains a shock mounted, thin and compact micro-Winchester head and disk assembly which plugs into a base housing which is installable entirely within a well of the computer nominally allotted to receive a 51/4 inch half height disk drive. The base housing includes a head positioning and data module loading/unloading portion of the subsystem control electronics and an electromechanical mechanism for automatically loading and unloading the hard disk module. The base housing provides electrical connections for operating the head and disk assembly when loaded therein. The subsystem further includes an adapter board having a host interface portion of the subsystem control electronics and connected by a cable with the control electronics portion of the base housing, the adapter board for connecting the subsystem directly to address, data and control buses of said computer to enable storage and retrieval in the loaded module of host computer data blocks.

Growing community of inventors

Livermore, CA, United States of America

David B Jeppson