Patent ID: 7551388
Filing Date: 2009-06-23
Classification: G01P,G11B

Abstract:
1. A magnetic disk drive comprising: a fall detection device; a head that reads or writes data relative to a magnetic disk; and a head evacuation unit arranged to evacuate the head to an evacuation area when the fall detection device detects a fall; wherein the fall detection device comprises: an acceleration sensor that outputs an output signal in accordance with acceleration; a differentiator arranged to differentiate the output signal of the acceleration sensor; an integrator arranged to integrate the output signal of the acceleration sensor; and a state determination processor arranged to determine a fall when the output signal of the acceleration sensor is in a specific state in which a differential signal from the differentiator goes beyond a predetermined threshold and an integrated signal obtained by the integrator goes beyond a predetermined threshold; wherein the integrator starts integration at a time when the differential signal from the differentiator goes beyond the predetermined threshold.