A disk drive includes an enclosure having a cover and a base, a spindle motor
assembly,
a disk, and an arcuate raised portion on the base. The disk is mounted on a hub
of the spindle motor assembly and has a first surface and a second surface. The
first surface is proximate the base and is spaced apart from the base by a first
clearance distance. The arcuate raised portion on the base is spaced apart from
the disk by a second clearance distance. The second clearance distance is less
than the first clearance distance. At least a portion of the disk is superposed
over the arcuate raised portion.
