Patent ID: 6344942
Filing Date: 2002-02-05
Classification: G11B

Abstract:
A method to determine and correct track spacing during self-servowriting on a rotating recording medium comprising a plurality of tracks, wherein each track comprises a plurality of sectors, and a transducer mounted on an actuator arm pivotally coupled to a voice coil motor (VCM), wherein a position of said actuator arm is controlled by a servo controller signal, said method comprising the steps of:servowriting with a servo pattern consisting of recorded transitions, at least one of said plurality of sectors comprising at least one said plurality of tracks wherein said plurality of tracks is less than a total number of tracks that fills said rotating recording medium; positioning said transducer relative to said rotating recording medium to a preselected radial position over a previously servowritten area of said rotating recording medium that has one or more previously recorded transitions; turning off said servo controller signal to said actuator arm and imposing a predetermined angular acceleration on said actuator arm by applying a predetermined amount of current to said VCM; and calibrating a spacing of said tracks in said previously servowritten area, by measuring the amplitudes of said previously recorded transitions at least one time during the passage of said sectors beneath said transducer, and if said calibrating of said spacing is outside a predetermined tolerance, then continuing servowriting new recorded transitions using an adjustment factor on tracks following said previously servowritten area.