Patent ID: 6476996
Filing Date: 2002-11-05
Classification: G11B

Abstract:
A disk drive comprising:a. a disk having a data area; b. a head; c. a spindle motor for spinning the disk; d. an actuator for positioning the head over the data area during a spindle speed control mode and retracting the head away from the data area during a spindle speed fault mode; e. a servo microprocessor for executing steps of a servo control program to generate a first control signal; f. an actuator driver circuit responsive to the first control signal for controlling the actuator during the spindle speed control mode; g. a spindle speed detector for generating a spindle speed signal representing a spin rate of the spindle motor; and h. a spindle speed fault detector responsive to the spindle speed signal for detecting the spindle speed fault mode, the spindle speed fault detector generates a second control signal in response to the detected spindle speed fault mode; and wherein the actuator driver circuit is responsive to the second control signal so that the actuator retracts the head away from the data area independent of the servo microprocessor during the spindle speed fault mode.