Abstract: Method and system aspects for nulling output offset current in an amplifier are described. In an exemplary method aspect, the method includes determining at least one offset value with a power amplifier in at least one mode. The at least one offset value then utilized to identify an output offset current value in the power amplifier. An adjustment to an input signal to the power amplifier occurs until the output offset current value is substantially nulled to identify a power amplifier offset value.

Abstract: An adaptive technique for calibrating a disk drive based on real time measurements. The invention includes a sensor for measuring a performance characteristics of a disk drive, a control circuit for comparing the measured performance characteristics to reference characteristics, and memory for storing performance parameters. The performance parameters are updated when the measured performance characteristics differs from the reference characteristic by a predetermined value, and the processor performs drive operations in accordance with the updated performance parameters. In the specific embodiments, the performance characteristic include disk runout and seek settle performance. A calibration flag may be set in the interface processor in response to the comparison of the measured performance characteristics to reference characteristics.