METHOD AND APPARATUS FOR PHASE MODULATED SERVO POSITIONING IN A DIRECT ACCESS STORAGE DEVICE

摘要

A phase modulated servo method and apparatus are provided for use in a disk file. The disk file includes at least one disk mounted for rotation about an axis and the disk has at least one disk surface for storing data. At a predefined location of the disk surface a series of servo tracks of a predetermined high gain servo pattern are written. The predetermined high gain servo pattern includes 360.degree. phase difference information within each data cylinder. The servo tracks are detected for identifying servo phase information.