Abstract: A method is disclosed for setting an operating bias current for a magnetoresistive (MR) element. A bias current is applied to the MR element, and a voltage across the MR element is measured corresponding to the bias current. The bias current is then adjusted in response to the bias current multiplied by a ratio of a target voltage and the measured voltage. The adjusted bias current is then applied to the MR element. In one embodiment, the bias current is adjusted until the measured voltage substantially equals the target voltage.

Abstract: A disk drive is disclosed comprising a disk including a plurality of servo sectors, a head actuated over the disk, the head for generating a read signal, and a gain control circuit for adjusting a gain of the read signal in response to a gain setting. A bias setting is initialized for the head, and the gain setting for the read signal is initialized. The read signal is processed to detect at least one of the servo sectors, and when at least one of the servo sectors is not detected, the gain setting is adjusted. The read signal is processed with the adjusted gain setting to detect at least one of the servo sectors, and when at least one of the servo sectors is not detected with the adjusted gain setting, the bias setting is adjusted in response to the adjusted gain setting.