Patent ID: 8619383

Claim:
A disk drive comprising: a first disk surface comprising a plurality of zones, each zone comprising a plurality of tracks; a first head actuated radially over the first disk surface to write data to the first disk surface and read data from the first disk surface; and control circuitry coupled to the first head, the control circuitry operable to: (a) set the first head to a first fly height over a first zone of the first disk surface; (b) write a data pattern on a first track in the first zone of the first disk surface; (c) read the data pattern to determine a first value of a first metric; (d) erase the data pattern after reading the data pattern; (e) write a first frequency pattern on the first track in the first zone of the first disk surface; (f) determine an initial amplitude of the first frequency pattern; (g) write a second frequency pattern over the first frequency pattern; (h) determine a first value of a second metric for the first frequency pattern; and (i) determine a first fly height value for the first zone of the first disk surface by utilizing the first value of the first metric and the first value of the second metric.