Disk drive reducing write unsafe threshold when detecting an unrecoverable servo compensation value

摘要

A disk drive is disclosed comprising a disk comprising a plurality of servo tracks defined by servo sectors, wherein each servo sector comprises servo data and a servo compensation value. While servoing a head over a target data track during a write operation, a position error signal (PES) is generated at each servo sector based at least in part on the servo data. When the servo compensation value of a first servo sector is recoverable, the write operation is aborted when the PES generated at the first servo sector exceeds a first write unsafe threshold. When the servo compensation value of the first servo sector is unrecoverable, the write operation is aborted when the PES generated at the first servo sector exceeds a second write unsafe threshold less than the first write unsafe threshold.

主权项

1. A disk drive comprising:
a disk comprising a plurality of servo tracks defined by servo sectors, wherein each servo sector comprises servo data and a servo compensation value; a head actuated over the disk; and control circuitry operable to:
define a plurality of data tracks relative to the servo tracks; andwhile servoing the head over a target data track during a first write operation:
generate a position error signal (PES) at each servo sector based at least in part on the servo data;when the servo compensation value of a first servo sector is recoverable, abort the first write operation when the PES generated at the first servo sector exceeds a first write unsafe threshold;when the servo compensation value of the first servo sector is unrecoverable, abort the first write operation when the PES generated at the first servo sector exceeds a second write unsafe threshold less than the first write unsafe threshold; recover the servo compensation value from at least two other servo sectors in the target data track; and generate the second write unsafe threshold based on the servo compensation values recovered from the at least two other servo sectors.