Patent ID: 6891696

Claim:
A disk drive comprising: an enclosure having a cover and a base; a spindle motor assembly mounted on the enclosure, the spindle motor assembly including a hub that is rotatable with respect to the enclosure; a disk mounted on the hub, the disk having a first surface, a second surface, and an outer periphery, the first surface being substantially parallel to a portion of the base located beneath the first surface and radially between the hub of the spindle motor assemble and a projection of the outer periphery, the first surface being spaced apart from the base by a first clearance distance; and an arcuate raised portion on the base substantially parallel to the disk and spaced apart from the disk by a second clearance distance that is less than the first clearance distance, at least a portion of the disk superposed over at least a portion of the arcuate raised portion, wherein the arcuate raised portion subtends a central angle of at least about 180 degrees.