In a magnetic disk drive that performs the seek operation of a magnetic head
by
a VCM, a characteristic that is excellent in fault tolerance that will not generate
a fault in severe environment, such as a high temperature and the issue of high
frequency command without requiring a special device and special operation and
without deteriorating access performance.
For this purpose, a VCM current and a VCM voltage are measured and VCM back electromotive
force is calculated based on both results. At seek operation, position information
located on a magnetic disk is sampled and a traveling velocity is detected from
the difference of the sampled result. VCM coil temperature is estimated from the
difference between the traveling velocity and the VCM back electromotive force.
The magnetic disk drive moves low velocity seek mode when the estimated value of
this VCM coil temperature exceeded a specified value.
