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 adisk file. The disk file includes at least one disk mounted for rotationabout an axis and the disk has at least one disk surface for storing data. Ata predefined location of the disk surface a series of servo tracks of apredetermined high gain servo pattern are written. The predetermined highgain servo pattern includes 360° phase difference information within each datacylinder. The servo tracks are detected for identifying servo phaseinformation.