International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Other

Michael Joseph Ross

Richard Leo Galbraith

Hal Hjalmar Ottesen

Weldon Mark Hanson

Travis Roger Oenning

Nathaniel C Anderson

Mohammed Amine Hajji

Evangelos Stavros Eleftheriou

Roy Daron Cideciyan

Thomas Mittelholzer

Ajay Dholakia

Fuminori Sai

David James Stanek

Charles C Hanson

Kraig Bottemiller

A billiard rack is provided that includes a frame that extends around an interior space that is configured to receive a set of billiard balls resting on a bed of a billiard table. A bottom side of the frame includes a lower opening in which the upper portions of the set of billiard balls are able to extend therein. The frame also includes an inner wall having at least one cam surface that extends at least partially around the interior space and that tapers inwardly in directions from the lower opening to an upper opening. When the frame is placed on the set of billiard balls resting on the bed of the billiard table, the at least one cam surface is configured to contact all of the peripheral billiard balls of the set of billiard balls; and urge the set of billiard balls together without the rack contacting the billiard table.

Billiard rack

The invention includes apparatus and methods that allow a data storage device perform an enhanced data recovery procedure (DRP) that includes obtaining a new digital sampling of the voltages for the failing unit of data by re-reading the analog signal and converting it to digital form using an analog-to-digital conversion (ADC) using a fixed phase clock signal. The data samples are re-interpolated using a programmable delay line. The digital values representing the voltages are stored a buffer so that the data can be processed repeatedly using varying parameters as part of the data recovery procedure. Optionally the samples stored in the buffer can be processed in the reverse direction (from end of sector to beginning of sector) without requiring modification of the standard Viterbi detector since it inherently works on data processed in either direction.

Data storage device with data recovery process using fixed phase clocking for analog-to-digital conversion

An apparatus for providing dynamic equalizer optimization is disclosed. The present invention solves the above-described problems by providing equalizer coefficient updates that converge towards the same solution as the direct method without having to first write a known pattern to the disk or requiring any prior knowledge of the data already written on the disk. The adaptive cosine function may be used to modify only a DFIR tap set, only the j and k parameters of a cosine equalizer or to modify both the tap set for a DFIR filter and the j and k parameters of the cosine equalizer. Another algorithm, such as the LMS algorithm, may be used to modify parameters not modified by the cosine algorithm.

Apparatus for providing dynamic equalizer optimization

A magnetic disk drive includes redundant data written at a plurality of out of phase angular locations to reduce the latency and enhance performance during a read operation. The loss of recording capacity is reduced by increasing the data density to achieve the same soft error rate standard required for single recording. Dual recording also allows different recording codes to be used at the duplicated locations to thereby have the more highly stressed code words occur at different locations in the data to further reduce the possibility of an error. The redundant recording can be used in one portion of the media and normal recording used in another media portion to enable selection of the recording technique in accordance with the type of data being stored. The size of the normal and redundant recording portions can be controlled by the format operation and the user of the disk drive can intervene to designate the size of the redundant and normal media recording portions effected during the format operation.

Data recording device and control apparatus for recording data twice on

Disk drive with redundant recording

One phase of a multi-phase spindle motor, normally used to rotate the disk of a disk drive system when power is on, is used to supply power to a capacitor storage circuit when power is lost (turned off or otherwise interrupted). The capacitor storage circuit provides the power to the retract circuit, which retracts the head. The combination of the generator effect of the phase and the capacitor storage circuit provides power to the retract circuit for a time clearly sufficient to reliably retract and lock the head regardless of the bias of the head prior to power loss. Simultaneously with one phase being used to retract the head, the other phases are shorted together to provide regenerative braking. FET drivers, normally used to drive the spindle motor when power is supplied, are used to short out the remaining phases to brake the motor when power is lost. In the preferred embodiment, the capacitor storage circuit is used as a line filter circuit when power is on. Therefore, the major circuit components used for retracting the head and braking the motor upon loss of power (capacitor storage circuit, motor windings, FET drivers) are all used for different purposes when power is on. This efficient use of the same circuitry for multiple purposes results in an efficient, reliable, compact, and relatively inexpensive approach for disk drive head retract and motor braking upon loss of power.

Disk drive head retract and motor braking method and apparatus

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Rochester, MN, United States of America

Michael Joseph Ross