Abstract: Disk drive preconditioning allows the head-disk interface to be burnished or worn so that head-disk interference is reduced or eliminated before servo track writing. The head is positioned closer to the disk than the normal fly height during a preconditioning sweep and then returns to the normal fly height during servo track writing.

Abstract: A method and apparatus is provided for measuring a media thermal decay rate for a disk in a disk drive. In one embodiment, reference patterns are written in a plurality of reference sectors on a test track of a disk surface. A thermal decay measurement duration is predetermined. After at least two decades of time longer than the predetermined thermal decay measurement duration have passed since writing the reference patterns in the plurality of reference sectors, sector-under-test patterns are written in a plurality of sectors-under-test, wherein the sectors-under-test and the reference sectors are written in data sectors and alternate with one another about at least a portion of the test track. The mean square error is measured and averaged for the reference sectors, and the mean square error is measured and averaged for the sectors under test.