A method and apparatus for compensating for head-to-disk contact-induced
disturbances in a hard disk drive is disclosed. The method includes
determining topographical variations across a surface of a disk during
the manufacturing or operation of the hard disk drive. Error signal
variations that occur as a result of head-to-disk contact-induced
disturbances resulting from the topographical variations are recorded.
Current to a voice coil motor in the hard disk drive is varied to correct
for the contact-induced disturbances before they occur.