Patent ID: 6963465

Claim:
A method for preventing radial error propagation during self-servowriting of concentric tracks on a magnetic disk in a disk drive, wherein each written track comprises a plurality of embedded servo sectors that define a circumferential path and that eventually form corresponding servo wedges extending radially across the magnetic disk such that each servo sector t of a track corresponds to a particular servo wedge, the method comprising: track following along a previously written track k and determining a position error signal e for each servo sector t; recursively estimating a correction value u for each servo sector t of an adjacent track k+1 based on the equation: u k+1 ( t )=α 0 e k ( t )+α 1 e k ( t+ 1)+α 2 e k ( t+ 2)+α 3 e k ( t+ 3) where k is the track number, t is the sector number for a sector corresponding to a particular wedge, and α 0 , α 1 , α 2 , and α 3 are learning gain coefficients; and wherein the correction value u k+1 (t) is for use in correcting a position error signal e k+1 (t) determined using the corresponding servo sector t of the adjacent track k+1 to prevent radial error propagation from track k to track k+1.