Method of generating a position error signal,method of writing a data track,and method and apparatus for testing a head

摘要

A method of generating a position error signal for a desired radial position of a read/write head relative to a data track of a disk (1) is disclosed. In the method the track has a plurality of servo bursts defining a plurality of servo nulls (108) for the track (101), the servo nulls being positioned such that there are servo nulls at more than four different radial positions relative to the track, the servo nulls defining a predetermined locus (24) e.g. aspiral, having a known position relationship with the track (101), the locus extending across the radial extent of the track (101) and a method for testing a read/write head.