Patent ID: 7502192

Claim:
A method for determining and writing repeatable runout (RRO) compensation value sets for data tracks on a magnetic disk in a disk drive, the disk drive having the disk, an actuator arm, a voice coil motor (VCM) for rotating the actuator arm about a pivot, a magnetoresistive (MR) head having a read element and a separate write element, and a secondary actuator coupled to a distal end of the actuator arm for adjusting a skew angle for the head, wherein each data track comprises a plurality of embedded servo sectors that define a circumferential path having repeatable runout error, the method comprising: track following along a first data track; setting the skew angle for the MR head using the secondary actuator such that the read element and the write element are substantially aligned along the first data track; determining a position error signal for each servo sector over a predetermined number of disk revolutions; calculating a repeatable runout compensation value set for the first data track based on the position error signals determined by track following along the first data track; continuing the step of track following along the first data track while writing the repeatable runout compensation value set for the first data track; and performing a seek operation to a second data track.