Embodiments of the invention reduce the noise occurring when the
lubricating layer on the magnetic disk is smoothed. In one embodiment, a
magnetic disk drive has a read/write mode parameter table for generating
an electric current to be supplied to a voice coil motor when the
magnetic head performs data read/write operations on the magnetic disk.
The magnetic disk drive also has a smoothing mode parameter table for
generating another electric current to be supplied to the voice coil
motor when neither a data read nor a write operation is performed on the
magnetic disk. The CPU refers to either the read/write mode parameter
table or the smoothing mode parameter table and controls the electric
current to be supplied to the voice coil motor. When a lubricating-layer
smoothing event occurs, the CPU refers to the smoothing mode parameter
table and after generating the associated electric current to be supplied
to the voice coil motor, moves the magnetic head to seek between the
outermost and innermost tracks on the surface of the magnetic disk to
perform a smoothing process for the lubricating layer.