Magnetic recording disk and disk drive with amplitude-type servo fields having patterned alternating-polarity servo islands for read/write head positioning

摘要

A magnetic recording disk drive has a disk with pre-patterned nondata servo sectors extending generally radially across the data tracks for use in positioning the read/write heads on the data tracks. The servo sectors include a synchronization pattern of generally radially directed magnetized marks, a first field of generally radially directed magnetized stripes, and a second field of generally radially directed magnetized stripes. Each stripe in each of the two fields comprises a plurality of radially spaced discrete islands, each island having a radial height of approximately Tp, where Tp is the spacing of the track centerlines in the radial direction. In the first field, the islands are centered at a track centerline, and in the second field the islands are centered at the midline between two adjacent track centerlines. The marks and islands are discrete magnetized regions separated by nonmagnetic spaces. The marks in the synchronization pattern and the stripes in the two fields have alternating polarity of magnetizations in the along-the-track direction.