A disk drive is disclosed comprising a voice coil motor (VCM) for rotating
an actuator arm about a pivot in order to actuate a head over a disk. The
disk is rotated by a spindle motor, and a feed-forward compensation value
is computed that compensate for a non-centric alignment of the disk with
respect to the spindle motor. During a calibration mode, the VCM is
controlled to press the actuator arm against a crash stop, and the
feed-forward compensation value is computed in response to a position
error signal (PES). The PES is generated in response to embedded servo
sectors recorded on the disk, wherein each embedded servo sector
comprises a track address for coarse alignment and servo bursts for fine
alignment.