Patent ID: 6735041
Filing Date: 2004-05-11
Classification: G11B

Abstract:
In a disk drive having a transducer head, a magnetic disk with a spiral track, and an actuator for moving the head across and positioning the head over a surface of the magnetic disk in response to control currents, the magnetic disk rotating at a constant angular velocity and the spiral track having contiguous storage segments, each storage segment including a servo sector and a predetermined number of data sectors, the storage segments being situated along the spiral track such that the servo sectors may not be aligned along a radius of the magnetic disk, a method for seeking from a current storage segment at a first radial position to a desired storage segment at a second radial position, comprising:determining a head transit time for moving the head from the first radial position to the second radial position according to a desired velocity profile; applying a first control current pulse to the actuator, wherein the first control current pulse has an amplitude and a duration designed to cause the head to move from the first radial position toward the second radial position at a coast velocity resulting solely from the application of the first current pulse and not resulting from a velocity measurement during the head movement from the first radial position to the second radial position; after applying the first control current pulse to the actuator, commencing a timer for measuring the expiration of the head transit time after applying the first control current pulse; after expiration of the head transit time, applying a second control current pulse to the actuator to terminate the head movement; and after applying the second control current pulse, reading at least one servo sector along the spiral track to locate the position of the head with respect to the desired storage segment.