Hewlett-packard Company

Charles E Hessing

Donald J Fasen

Boyd N Shelton

Benjamin A Willcocks

Robert K Barnes

A timing-based servo system for positioning a magnetic head relative to a magnetic storage medium, the magnetic storage medium having a servo pattern written thereon, the system comprising a head including a servo read element configured to read the servo pattern and produce a signal, the signal including recognizable signal events corresponding to the servo read element reading servo transitions; a servo decoder configured to receive the servo signal, determine the position of the head, with respect to the servo band, in response to the amount of time between the signal events, and generate an error signal indicative of actual head position relative to desired head position with respect to the servo band, the servo decoder including time capture logic configured to determine the amount of time between the signal events, the time capture logic including a multiple phase clock generator. A servo method for positioning a magnetic head relative to a magnetic storage medium, the magnetic storage medium having a servo pattern written thereon, the head including a servo read element configured to read the servo pattern and produce a signal, the signal including recognizable signal events corresponding to the servo read element reading servo transitions, the method comprising receiving the servo signal, and determining the position of the head, with respect to the servo band, by determining the amount of time between the signal events.

Servo system and method with multiple phase clock

An adaptive media speed drive unit for use with a magnetic storage medium, the magnetic storage medium having a timing based servo pattern written thereon, the servo pattern including transitions, the drive unit including a magnetic head including a servo read element configured to read the servo pattern and produce a signal, the signal including recognizable signal events corresponding to the servo read element reading servo transitions; a servo decoder including time capture logic configured to determine the amount of time between the signal events; and a digitally controlled oscillator configured to produce a tracking clock which a write element can use to write data to the magnetic medium with a uniform spacing regardless of magnetic medium speed. A method for producing a tracking clock signal used for writing data in an equally spaced manner to a magnetic medium unit, the magnetic storage medium having a servo pattern written thereon, the servo pattern including transitions, the magnetic medium being movable relative to a magnetic head and the head including a servo read element configured to read the servo pattern and produce a signal, the signal including recognizable signal events corresponding to the servo read element reading servo transitions, the method comprising receiving the servo signal, and determining the speed of the magnetic medium, with respect to the head, by determining the amount of time between the signal events; and producing the tracking clock.

Servo system and method with digitally controlled oscillator

A disk drive has a disk format that includes servo fields and interspersed data fields. The disk drive includes a timing generator for generating timing signals to synchronize and control operation of read/write and servo positioning circuits. The disk drive also includes a writable program store that stores a plurality of timing signal commands for generating timing signals in conformance with the format of a disk. A processor loads the writable program store with the timing signal commands and the processor further enables readout of those commands from the writable program store. An execution register receives the timing signal commands and generates timing signals in response, the timing signals controlling synchronization and operation of the read/write circuits. As the writable program store is reprogrammable, at will, substantial flexibility is achieved in the creation of such timing signals.

Programmable servo timing generator

A disk drive system employs uniform size data blocks, with each disk having a sectorized track format and each sector of a track including at least one servo burst. Data blocks exhibit a constant data density across a plurality of disk tracks of differing radii. The system comprises read/write apparatus for accessing both servo signals and data signals in each disk sector. A servo system is responsive to servo signals fed from the read/write apparatus to generate a synchronizing signal. A data sector pulse generation circuit is responsive to the synchronizing signal to generate and pass to the read/write apparatus, a data sector pulse for each block of data commencing in a sector. That data sector pulse enables operation of the read/write apparatus upon the data block. A control circuit enables the delay of generation of a next data sector pulse when any block of data is split by a servo burst. The delay period is the duration of the servo burst and the portion of the data block that follows the servo burst.

Growing community of inventors

Boise, ID, United States of America

Charles E Hessing