Track pitch variation measurement method using spiral DC pattern writing

摘要

In one embodiment, a method includes spiral writing a DC pattern onto a magnetic disk medium using a writer of a magnetic head while moving the magnetic head in a direction about parallel to a radial direction of the magnetic disk medium while rotating the magnetic disk medium, reading the magnetic disk medium while moving the magnetic head in the direction about parallel to the radial direction of the magnetic disk medium while rotating the magnetic disk medium, and calculating a track pitch interval between data tracks of the magnetic disk medium based on the reading of the magnetic disk medium. In another embodiment, a magnetic disk medium includes a DC spiral pattern in a radial region further outward and/or a radial region further inward than a radial region where data is recorded.