Western Digital Corporation

Greg Kittilson

Timothy W Swatosh

Mark R Schibilla

A disk drive employs a method for writing a block of data (or multiple blocks of data) to a data region following a defective servo sectors. The disk drive includes a sampled head positioning servo system and a rotating disk with a plurality of data tracks on a surface of the disk. Each data track has multiple spaced-apart sequentially-active servo sectors. Data regions are disposed between the servo sectors. The method includes the step of executing a command to perform a write operation to write a data block to a target data region. A defective servo sector S.sub.n is encountered preceding the target data region during the write operation. The defective servo sector S.sub.n precedes a servo sector S.sub.n+1 and follows a servo sector S.sub.n-1. A timer interval is set to enable a first detection window Dw.sub.n+1 for detecting a field in servo sector S.sub.n+1 . If the field is detected within the detection window Dw.sub.n+1, a field is detected within a detection window Dw.sub.n-1 for the servo sector S.sub.n-1. The data block is written in the target data region following the defective servo sector S.sub.n based on detecting the field within the detection window Dw.sub.n-1 for the servo sector S.sub.n-1 . A timer interval is set to enable a second detection window Dw.sub.n+1 for detecting a field in the servo sector S.sub.n+1 . If the field in the servo sector S.sub.n+1 is detected within the second detection window Dw.sub.n+1, the data block is marked as being successfully written.

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Rochester, MN, United States of America

Greg Kittilson