Patents Examined by Hda T. Nguyen
  • Patent number: 7136251
    Abstract: To account for head misplacement while servowriting, adjustments to thresholds used during writing and/or trimming of servo information can be used. A threshold can be used to disable servowriting when it is determined that servo information will not be written and/or trimmed at a desired location or within a threshold distance of a desired location. In multiple pass servowriting, a threshold can be adjusted for a pass or step or portion thereof using a position-error during a corresponding operation. For example, the position-error while trimming a first servo burst can be determined. Using the position-error, the threshold can be adjusted. The adjusted threshold can be used while writing a corresponding second servo burst. The threshold can be increased in a direction opposite to the determined position-error and decreased in the direction of the determined position-error. In this manner, the probability that the two bursts will identify a desired location can be increased.
    Type: Grant
    Filed: December 20, 2004
    Date of Patent: November 14, 2006
    Assignee: Matsushita Electric Industrial, Co., Ltd.
    Inventors: Richard M. Ehrlich, Thorsten Schmidt