Patent ID: 7428119
Filing Date: 2008-09-23
Classification: G11B

Abstract:
1. A magnetic disk drive comprising: a magnetic disk; a head which accesses the magnetic disk; a sensor section configured to detect an acceleration; a first judgment section which judges whether a drop is occurring based on an output of the sensor section; a processing section which executes a retraction of the head if the first judgment section judges that a drop is occurring; and a second judgment section which detects the occurrence of a shock based on the output of the sensor section; wherein, after the first judgment section judges that a drop is occurring, the processing section detects whether the drop judgment is incorrect according to whether the occurrence of a shock is detected by the second judgment section and changes the drop judgment condition of the first judgment section based on a history of detected incorrect drop judgments, wherein if the number of incorrect drop judgments exceeds a predetermined number, the processing section changes the judgment condition of the first judgment section so as to more stringently make a drop judgment.