Patent ID: 8717704

Claim:
A disk drive comprising: a disk comprising a plurality of servo tracks defined by servo sectors; a head actuated over the disk; and control circuitry comprising a servo control system operable to: measure a position of a head over the disk to generate a position signal; generate a position error signal (PES) representing a difference between the position signal and a reference signal; process the PES with a servo compensator to generate a control signal; and position the head over the disk in response to the control signal; wherein the control circuitry is further operable to: induce a disturbance in the servo control system; and while positioning the head over the disk in response to the control signal, access a data track, wherein the disturbance induced in the servo control system causes the data track to be non-circular relative to a rotation axis of the disk such that a center of the non-circular data track crosses multiple of the servo tracks over a revolution of the disk.