Quantum Corporation

Shugart Associates, Inc.

David A Brown

Joel N Harrison

Donald V Daniels

Herbert E Thompson

Albert S Chou

Harold C Medley

Peter A Ronzani

Ray Y Yokoyama

Daniels Donald V

A servo calibration method is disclosed for a disk drive including a rotating data storage disk journalled to a frame and having a multiplicity of concentric data tracks defined on a major surface thereof and an actuator structure under the control of a programmed servo control microprocessor in response to coarse position information fed back to the microprocessor by a position encoder, and to fine position information fed back to the microprocessor by a data transducer reading from servo information prerecordced on the major surface of the disk, the actuator structure for moving the data transducer to each selected one of the data tracks during track seeking operations and for maintaining the transducer aligned with the data track during track following data read and/or write operations. Carried out during initialization, the method includes the steps of: automatically seeking to a region of radially outermost tracks, reading fine position information recorded in the single sector of each of a plurality of outermost tracks, and recording the outer track fine position information in memory; automatically seeking to a region of radially innermost tracks, reading fine position information recorded in the single sector of each of a plurality of innermost tracks, and recording the inner track fine position information in memory; for each data track to which a seek is initially commanded, which track lies between the outermost track region and the innermost track region, calculating with the microprocessor means a track centerline correction value lying between the outer track fine position information and the inner track fine position information, and applying the track centerline correction value so calculated as an offset value to the rotary actuator to correct any discrepancy between nominal track centerline defined by the position encoder.

Data transducer position control system for rotating disk data storage

A head and disk assembly for a fixed disk drive including control electronics and a host computer associated therewith comprises a frame and a cover for providing an interior space enclosed from the ambient; at least one data storage disk mounted within the interior space; the data storage disk having a data storage surface defining a multiplicity of concentric data storage tracks for storing user data and further defining factory prerecorded track centerline correction information which may be periodically sampled, held and processed by the control electronics; a disk rotation motor for rotating the disk relative to the frame at a predetermined angular velocity; a mass balanced, direct drive rotary actuator for positioning a data read/write head relative to the tracks in response to positioning signals supplied by the control electronics; an optical polyphase head position transducer coupled closely to the rotary actuator and the frame for generating plural phase cyclical signals e.g. in quandrature and for supplying the signals to the control electronics, at least four adjacent data track locations being included within a range of movement of the rotary actuator relative to the frame and disk within one cycle of one of the plural phases; whereby the control electronics may respond to commands from the host computer, to the plural phase cyclical signals and to the factory prerecorded track centerline correction information in order to generate and apply positioning signals to move the read/write head from track to track during seeking operations and to maintain the read/write head within within each data track during track following operations for reading and writing user data from and to a said track being followed.

Head and disk assembly for fixed disk drive

A higher performance, higher capacity, low cost fixed (Winchester) disk drive avoids the need of a servo surface and servo channel for head positioning by use of a mass balanced rotary actuator, a polyphase optical head position transducer coupled closely to the actuator and head position correction information sampled from the data surface by the data head.

Fixed disk drive

A data storage device includes a frame, a rotating data storage disk defining a multiplicity of concentric data tracks on the major surfaces thereof and at least one data transducer head in close proximity to a said disk surface. A bidirectionally moveable electromechanical mover includes a microstep providing stepping motor supported by the frame. The electromechanical mover is moveable between and stabilized at a position related to each data track. A head mounting structure moved by the mover moves the head across the multiplicity of concentric data tracks. A bidirectional mover driver connected to the mover moves the structure to any selected one of said concentric data tracks in accordance with externally supplied track position information and maintains the structure substantially within data track during read and/or write operations by reference to the frame. A data track stabilization means includes the stepping motor and stabilizes the structure within a range between the boundaries of each data track. A time sampled fine position closed loop servo is connected to the driver and includes a single, data masked servo sector on a data surface of said disk containing track centerline servo control data therein readable by said head, a sample and hold circuit connected to the head during passes over the servo sector for holding control data read therefrom, and a correction signal generator connected to the sample and hold circuit for generating an offset signal for application to said driver to promote and maintain track centerline alignment of the head during read and write operations.

A servo calibration method is disclosed for a disk drive including a rotating data storage disk journalled to a frame and having a multiplicity of concentric data tracks defined on a major surface thereof and an actuator structure under the control of a programmed servo control microprocessor in response to coarse position information fed back to the microprocessor by a position encoder, and to fine position information fed back to the microprocessor by a data transducer reading from servo information prerecorded on the major surface of the disk, the actuator structure for moving the data transducer to each selected one of the data tracks during track seeking operations and for maintaining the transducer aligned with the data track during track following data read and/or write operations. Carried out during initialization, the method includes the steps of: automatically seeking to a region of radially outermost tracks, reading fine position information recorded in the single sector of each of a plurality of outermost tracks, and recording the outer track fine position information in memory; automatically seeking to a region of radially innermost tracks, reading fine position information recorded in the single sector of each of a plurality of innermost tracks, and recording the inner track fine position information in memory; for each data track to which a seek is initially commanded, which track lies between the outermost track region and the innermost track region, calculating with the microprocessor means a track centerline correction value lying between the outer track fine position information and the inner track fine position information, and applying the track centerline correction value so calculated as an offset value to the rotary actuator to correct any discrepancy between nominal track centerline defined by the position encoder.

An improved apparatus and method is disclosed for controlling the position of one moveable member relative to another. In the disclosed preferred embodiment of a rotating disk memory system, the moving member is a head carriage structure and the other is a frame carrying a rotating data storage disk. From externally supplied position selectron information, and from internally determined polyphase position information, open loop position changing movements are determined and carried out in accordance with monitored incremental polyphase position information generated during the movement. When a destination location has been reached one or more servo systems close loop in order to maintain the moving member precisely at the newly commanded location. A rotor for moving the member is an aspect of the present invention.

A bidirectional, pure torque generating electromechanical rotor mounted to a frame includes flux return top and base plates, a generally annular permanent magnet secured to one of the plates and a generally annular rotatable coil assembly placed between the permanent magnet and the other of the plates.

Pure torque, limited displacement transducer

Flexible disk drive

A magnetic head assembly and the method of manufacture therefor comprising a generally cylindrical housing having a tapered portion at one end thereof terminating in a circular aperture having an inner diameter, a circular slider body having an outer diameter slightly less than the inner diameter, a media engaging surface and an internal surface and being disposed within the circular aperture and affixed to the housing. The body also includes a first elongated slot disposed along a first diameter and extending through the body, a second slot disposed along a second diameter normal to the first diameter and extending into the body from the internal surface, and a central aperture extending through the body at the intersection of the first and second slots. A read/write transducer has a pair of read/write pole pieces which are separated to provide a read/write gap and which extend into the first slot with the read/write gap positioned with the central aperture. An erase transducer including a pair of erase pole pieces is disposed in the second slot with one-pole piece on each side of the first slot. The ends of the erase pole pieces nearest the read/write pole piece extend into the central aperture and are separated from the read/write pde pieces to form first and second erase gaps.

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Saratoga, CA, United States of America

David A Brown