Texas Instruments Corporation

James Schaffner

Kang Xiao

Joanne Wu

Dong Cho

Stephen Finch

Patrick Conley

Mark J Blair

The present invention provides a method and apparatus for providing position detection using a unique binary sequence encoded in indexing bits stored in servo wedges. The present invention generates a unique binary sequence (UBS) code and stores the bits of such a code in the indexing bits of the servo wedges. The bits are read from the servo wedges and used to provide unique identification of head position. Each servo wedge and each data field can be uniquely identified, even servo wedges and data fields under different heads. The present invention may be used to provide initial position detection, position verification during normal operation, and position verification upon head switching. When used for position verification, the present invention uses a confidence block to determine the confidence level with which the head is believed to be correctly positioned. One or more programmable thresholds may be used to qualify operations such as reading information from a disk, writing information to a disk, or seeking a location on a disk. If these thresholds are not met for the corresponding operations, the initial position detection capability of the present invention may be used to provide position recovery.

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Niwot, CO, United States of America

James Schaffner