A method is disclosed for efficiently determining and writing repeatable
runout (RRO) compensation value sets for data tracks on a magnetic disk
in a disk drive. The disk drive has a magnetoresistive (MR) head having a
read element and a separate write element, and a secondary actuator
coupled to the end of a primary actuator for adjusting a head skew angle.
In the method, the head skew angle is set such that the read and write
elements are substantially aligned along the first track. A position
error signal for each servo sector is determined over a predetermined
number of disk revolutions during track following along a first data
track. An RRO compensation value set is calculated for the first data
track based on the position error signals. The RRO compensation value set
is written for the first data track. A seek operation is then performed
to a second data track.