Abstract: A method including obtaining a target actuation efficiency slope that is a linear function of temperature when a fixed active clearance is maintained between a transducing head and an adjacent storage surface in a sealed storage device. The target efficiency slope is obtained at least in part by a temperature dependence calibration of actuation efficiency. An operating temperature of the storage device is measure. Power to a clearance adjustment mechanism is adjusted to achieve the target actuation efficiency slope at the measured operating temperature.

Abstract: A lumped-parameter function ? is determined that represents an average power dissipated by a write transducer when writing a signal to a magnetic recording medium. Temperatures of the write transducer are measured while varying the parameters to determine constants of the function ?. The function ? is used to adjust power applied to a clearance control heater when writing to the magnetic recording medium.

Abstract: A reference track written to a magnetic recording medium includes at least two harmonics that facilitate measuring a clearance between a read/write head and the recording medium. A magnetic field is applied to the reference track that accelerates a thermal decay of the reference track without erasing data of the reference track.

Abstract: A test track is written to a recording medium and includes a repeated series of reference patterns. The reference patterns each include a first portion with a high frequency pure tone and a second portion with a higher frequency component. A length of the first portion is greater than a length of the second portion. The series of reference patterns are read to determine first and second harmonic amplitudes, and a head-to-media clearance is determined based on the first and second amplitudes at first and second harmonic frequencies.