Xerox Corporation

Hewlett-packard Development Company, L.P.

Tandem Computers Incorporated

David L Griffith

Wing M Chan

Stipe Cizmic

James O Jacques

Martin O Halfhill

Leonard R Shenfield

Wayne L Edwards, Jr

Ronald W Votaw

Robert J Black

An on line serviceable computing system employing a small computer system interface (SCSI) bus architecture connecting two host computers to at least one additional shared device including a termination adapter circuit that can sense when a SCSI termination at the end of the SCSI bus is lost and automatically switch in a new SCSI bus termination to thereby ensure that the bus is terminated at both ends as required for continuous operation.

Automatic bus termination readjustment

Automatic SCSI termination readjustment

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

Growing community of inventors

Pleasanton, CA, United States of America

David L Griffith