Patent ID: 8537488

Claim:
A method for specifying a control value for controlling a clearance adjustment amount in a disk drive device in which a clearance between a head and a disk is adjustable, the method comprising: adjusting the clearance by varying the control value associated with a heater power at each of a plurality of different control values, said heater power directly associated with said clearance and during a calibration operation writing reference data onto the disk with the head at each of said plurality of different control values; retrieving during said calibration operation the reference data written at each of the plurality of different control values with the head and determining after error correction has been made on data retrieved with the head, whether or not the data have been properly written at each of the control values wherein correction capability in the error correction is lower than correction capability in a normal read operation of user data; specifying a control value for controlling a clearance adjustment amount in a normal operation based on a control value at which it has been determined that the reference data had not been written properly; writing data in a normal operation at said control value; retrieving the data written at one control value for a plurality of times; and performing the determination based on the plurality of times of retrieval.