Patent ID: 7075748
Filing Date: 2006-07-11
Classification: G11B

Abstract:
1. A disk drive comprising: a rotatable magnetic recording disk having a plurality of concentric data tracks in a data region and a plurality of calibration tracks in a nondata region, the data tracks containing servo positioning information and the calibration tracks containing radially-spaced magnetized test blocks; a recording head movable across the disk, the head being capable of reading data and servo positioning information in the data tracks and detecting the test blocks in the calibration tracks; a primary actuator for moving the head; a crash stop for limiting movement of the primary actuator and located to enable the head to detect the test blocks in the calibration tracks when the primary actuator is at the crash stop; a secondary actuator connected to the primary actuator, the head being connected to the secondary actuator; and a servo control processor responsive to servo information read by the head and comprising a dual-stage controller for generating a primary actuator control signal and a secondary actuator control signal, the processor capable of sending a crash stop signal to the primary actuator for moving the primary actuator to the crash stop and, when the primary actuator is at the crash stop, generating a test signal to the secondary actuator and receiving a calibration signal from the test blocks in response to the test signal.