Method and apparatus for runout correction by proper positioning of servo data while self-servo writing

A method for self writing track locations of a storage surface of a data disk of a disk drive, wherein the data disk includes a reference pattern for determining position information error for self-writing, the method comprising the steps of:

• generating position information based on the reference pattern;
• reducing any existing repeatable runout in the position information that is obtained from the reference pattern to obtain enhanced position information, and using the enhanced position information for self-writing servo bursts;
• self-writing first servo bursts along a circular track via a transducer and concurrently determining a position error due to repeatable runout at each of a plurality of points in the first servo burst pattern along the track addressed by the transducer head, and storing the position error;
• and
• calculating the repeatable runout correction values for the first servo burst pattern by:
• measuring a time domain impulse response of a disk drive servo control system associated with said transducer head;
• transforming said time domain impulse response into an error transfer function;
• taking the reciprocal of said error transfer function;
• transforming said reciprocal error transfer function into an inverse impulse response;
• and
• convolving said inverse impulse response with said position error at each of a plurality of said points in the first servo pattern to obtain a runout correction value for each of said plurality of points;
• and
• self-writing second servo bursts along the track via the transducer such that the first and second servo bursts form a plurality of servo sector patterns that define the track centerline, wherein the second servo bursts are positioned using said correction values to essentially compensate for the runout in the first servo bursts and reduce the overall track runout.

A hard disk drive having servo burst position correction, comprising:

• a base;
• a data disk comprising a reference pattern for providing position information to self-write final servo patterns in a plurality of data tracks arranged concentrically about a spindle, wherein each of said data tracks is segmented into a plurality of data sectors by servo sectors, wherein said disks may be rotated at a constant velocity with respect to said base;
• a transducer head for reading information from said data disk and for writing information to said data disk, wherein said transducer head is movable in a radial direction with respect to said disk to address a selected one of said plurality of data tracks;
• a voice coil motor, interconnected to said transducer head, for moving said transducer head with respect to said data tracks;
• a channel for receiving signals, including position error signals, derived from said disk by said transducer head;
• and
• a controller, interconnected to said voice coil motor, for controlling a position of said transducer head with respect to said reference pattern, wherein the controller writes final servo bursts on the data disk by self-writing first servo bursts along a circular track via the transducer, calculating repeatable runout correction values for the first servo bursts and self-writing second servo bursts along the track via the transducer such that the first and second servo bursts form a plurality of servo sector patterns that define the track centerline, wherein the second servo bursts are positioned using said correction values to essentially compensate for the runout in the first servo bursts and reduce the overall track runout.