MAGNETIC DISK APPARATUS AND ITS CONTROL METHOD

PROBLEM TO BE SOLVED: To provide a magnetic disk apparatus in which a head can be evacuated stably with simple constitution when a signal for positioning control cannot be detected due to a seek error or the like, and to provide its control method. SOLUTION: When the head 12 as the disk 10 cannot detect servo information, the positioning control part 22 starts reset of a clocking part 34, and switches output operation of a position control signal for a VCM driver 24 to a retraction control part 36. The clocking part 34 counts tacho-pulses generated by a motor driver 32 and outputs time information. The retraction control part 36 receives the time information from the clocking part 34, calculates the position control signal outputted to the VCM drive 24 from the positioning control part 22 based on this information, and decides it. At that time, the retraction control part 36 controls the VCM drive 24 so that the drive current to be supplied to a VCM 26 has such a current profile that it is small in the beginning and becomes large later. COPYRIGHT: (C)2006,JPO&NCIPI