Magnetic disk device and control method

Abstract

A magnetic disk device is a magnetic disk device in which data write is performed by a thermal assist method, the magnetic disk device including: a magnetic disk that includes a plurality of tracks; and a controller that controls the magnetic disk device, wherein the controller measures, every a first period, a deviation amount from a reference height of a surface of the magnetic disk with respect to a track in which a duty ratio is equal to or greater than a predetermined value, the duty ratio being a time ratio at which data write is performed per unit time, among the plurality of tracks, and flattens the surface of the magnetic disk in a case where the deviation amount becomes equal to or greater than a first value.

Dependencies are inferred from the claim text.