There is disclosed a disk drive using a disk medium in which a non-servo range
exists. In order to position a head at a target track, a CPU executes a seek operation
by normal velocity control using servo data. At this positioning, when the head
passes the non-servo range from which no servo data can be obtained, the CPU executes
a seek operation by special velocity control to move the head at a velocity calculated
based on a moving distance of the non-servo range.
