A servo track write method is disclosed in which, in a disk drive of a perpendicular
magnetic recording system, servo data is written with the use of a single magnetic
pole type head of the disk drive itself. In this method, the servo data is recorded
on a disk in those servo areas with the use of the single magnetic hole type head
mounted on the disk drive. A head mounted as the single magnetic pole type head
is position-controlled relative to the servo area by a servo track writer. The
servo data is recorded with perpendicular magnetization under a recording magnetic
field from the single magnetic pole type head in accordance with the magnetic pole
thickness of the single magnetic pole type head.
