A disk drive has a head fly-height actuator wherein the head-disk spacing
is controlled as a function of both the track, and the sector or sectors
within the track, where data is to be read or written. The fly-height
actuator may be a thermal actuator comprising a heater located on the
slider near the read/write head. The fly-height controller (FHC) for the
thermal actuator stores band control signal (BCS) values representative
of heater power (Hp) to be applied to the thermal actuator when reading
or writing to a data track in the associated band of tracks. The FHC also
either calculates from a programmed equation or recalls sector control
signal (SCS) values representative of an Hp increment to be applied to
the thermal actuator depending on the sector or sectors where data is to
be written. The FHC sums the appropriate SCS value with the appropriate
BCS value to achieve the desired Hp, resulting in the optimal fly-height
not only for the selected band but also for the selected sector or
sectors.