A disk drive includes a sampled servo controller for periodically adjusting a
control
effort signal during a track-following operation based on embedded distributed
position information and repeatable runout (RRO) cancellation values for reducing
effects of RRO in the distributed position information during track following.
A magnetic disk in the disk drive stores RRO information relating to predetermined
RRO cancellation values for a data storage track. The RRO information for the data
storage track includes at least one first data structure having a first predetermined
number of data bits for representing an initial RRO cancellation value, and includes
at least one second data structure having a second predetermined number of data
bits associated with a respective subsequent RRO cancellation value. The first
predetermined number of data bits is greater than the second predetermined number
of data bits.