Xerox Corporation

Stipe Cizmic

James O Jacques

Leonard R Shenfield

Martin O Halfhill

David L Griffith

Douglas K Mahon

Wayne L Edwards, Jr

Ronald W Votaw

Robert J Black

An exerciser is provided for use with a disk drive of the type having a microprocessor, a first memory for storing microcoded control programs for the drive, a second memory for storing instructions for the head carriage servo control apparatus, an address bus for supplying address signals from the microprocessor to the first and second memories, and a data bus for supplying program instructions from the first memory to the microprocessor, and for supplying instructions from the second memory to the servo control apparatus. The exerciser developes track address signals that are supplied onto the data bus for application to the microprocessor. A third memory is included in the exerciser for storing diagnostic programs. A decoder is also included for decoding an address signal on the address bus in order to generate a new address signal for the third memory. Program instructions accessed from the third memory are supplied onto the data bus for application to the microprocessor.

Self-diagnostic method and apparatus for disk drive

A velocity control apparatus for a disk drive of the type comprising a recording disk rotatable about its axis, an electromagnetic read/write head for reading data from and writing data onto tracks on a surface of the disk, and means coupled to the head and responsive to velocity command signals for controlling the direction and speed of movement of the head. The velocity control apparatus includes a memory divided into a plurality of sections respectively associated with different ranges of desired distances to be traveled by the head, each section containing a predetermined number of addressable storage locations together defining an approximation of a desired velocity trajectory curve for a desired distance to be traveled included within the range associated with said section.

Velocity control apparatus for disk drive

A disk drive comprises a housing having a door through which a cartridge including a recording disk therein may be inserted. A spindle drive assembly is mounted in the housing and is responsive to a first set of instructions for rotating the recording disk of a disk cartridge loaded into the housing through the door and onto the spindle drive assembly. An actuator is also mounted in the housing and is capable of controlled reciprocal movements relative to the axis of rotation of the spindle drive assembly. A head carriage assembly is mounted in the housing to the actuator and includes at least one electromagnetic read/write head thereon for reading data from the writing data onto tracks of the recording disk of a cartridge loaded onto the spindle drive assembly. Servo control apparatus is mounted in the housing and is responsive to a second set of instructions for controlling the speed and direction of the reciprocal movements of the actuator. Additionally, read/write apparatus is mounted in the housing and is responsive to a third set of instructions for controlling the reading and writing of data by the electromagnetic head. Further, programmed data processing means is mounted in the housing and is connected to the spindle drive assembly, the servo control system and the read/write apparatus for generating the first, second and third sets of instructions under program control.

Control system for disk drive

A method and apparatus for restoring the electromagnetic read/write head of a disk drive from a position between a data-field track located closest to the axis of rotation of a disk loaded in the drive and a data-field track located furthest to such axis of rotation, to a position over the latter data-field track. A first predetermined code is prerecorded on each data-field track and a second predetermined code is prerecorded on each of a plurality of guard-band tracks. The head is first moved in a direction away from the axis of rotation of the disk at a predetermined velocity. The code stored on each track is read and detected as the head is moved thereover. The head is stopped over a track when the code read and detected therefrom is the second predetermined code. Then, the head is moved in a direction toward the axis of rotation of the disk and stopped over the data-field track located furthest from the axis of rotation of the disk.

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San Mateo, CA, United States of America

Stipe Cizmic