Patent ID: 8749904
Filing Date: 2014-06-10
Classification: G11B

Abstract:
1. A servo writer operable to write servo sectors on a disk to define non-circular servo tracks, the servo writer comprising control circuitry including 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 operable to: induce a disturbance into the servo control system; and while positioning the head over the disk in response to the control signal, write a plurality of servo sectors on the disk to define a servo track, wherein the disturbance induced into the servo control system causes the servo track to be non-circular relative to a rotation axis of the disk.