Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of servo sectors that define a plurality of servo tracks. A position error signal (PES) is generated in response to the servo sectors, and a head velocity is estimated relative to the servo tracks. A correction value is generated as a function of the head velocity and the PES, and the PES is adjusted using the correction value to generate an adjusted PES. The head is positioned over the disk in response to the adjusted PES.

Abstract: A method for determining a position error signal in a disk drive includes writing a servo signal that has a variable offset from a track center for a plurality of concentric tracks in a servo wedge on a disk surface, forming a spiral servo track, observing the offset values for the servo signal in the servo wedges at a first of the plurality of tracks, and observing the offset values for the servo signal in the servo wedges at a second of the plurality of tracks. The method also includes determining the first error amounts from the offset values at the first of the plurality of tracks, and determining the second error amounts from the offset values at the second of the plurality of tracks. If the first error amounts and the second error amounts are equal, using one of the first or second error amounts as a correction update to a head non-linearity look-up table.

Abstract: Methods in accordance with the present invention can include determining a position of a head along a stroke by locating one or more marker-zones printed to a reference surface of a disk. The one or more marker-zones can be printed to a portion of the reference surface as one or more pulses from a template pattern that can further comprise a plurality of chevrons. In one embodiment, each pulse can trace the motion of the stroke along at least a portion of the radius of the reference surface. A pulse can identify a marker-zone edge when the pulse disappears at some radius from the center of the disk. By moving the head along the stroke, the marker-zone edge can be detected and a gross position determined. A fractional position can be determined by measuring a phase of a chevron located at substantially the same radial location as the edge.

Abstract: Template patterns in accordance with the present invention can include one or more marker-zones printed to a reference surface of a disk for determining gross-position along a stroke of a read head connected with a rotary actuator. The one or more marker-zones can be printed or otherwise written to a portion of the reference surfaces as one or more pulses. In one embodiment, each pulse can trace the motion of the stroke along at least a portion of the radius of the reference surface. A pulse can identify a marker-zone edge when a di-bit (a transition pair representing a pulse) disappears at some radius from center of the disk. At a radius closer to the center of the disk, the di-bit can abruptly reappear so that the pulse is continued. The interruption in the radial continuity of the magnetized pulse defines the marker-zone and can be any length.

Abstract: Embedded servo sectors within a data track of a hard disk drive including a rotating data storage disk and a closed loop rotary actuator structure for positioning a data transducer head relative to the data track are written by a method including the steps of positioning the rotary actuator structure relative to the data track with a laser-interferometer-based servo writer and writing a pattern of circumferentially sequential, radially offset fine position bursts within each servo sector with the data transducer head, this step including writing-in undetermined position errors within each pattern being written, moving the disk drive to a self scan environment away from the servo writer, operating the rotary actuator structure in closed loop for following the data track by reference to the servo burst pattern, extracting the undetermined position error from each pattern thereby to iteratively determine written-in position errors, generating burst correction values from the determined written-in position errors

Abstract: Embedded servo sectors within a data track of a hard disk drive including a rotating data storage disk and a closed loop rotary actuator structure for positioning a data transducer head relative to the data track are written by a method including the steps of positioning the rotary actuator structure relative to the data track with a laser-interferometer-based servo writer and writing a pattern of circumferentially sequential, radially offset fine position bursts within each servo sector with the data transducer head, this step including writing-in undetermined position errors within each pattern being written, moving the disk drive to a self scan environment away from the servo writer, operating the rotary actuator structure in closed loop for following the data track by reference to the servo burst pattern, extracting the undetermined position error from each pattern thereby to iteratively determine written-in position errors, generating burst correction values from the determined written-in position errors

Abstract: A disk drive includes an on-board digital sampling analyzer. The drive has a data storage disk spinning at a predetermined velocity, a data transducer head for reading information recorded on a storage surface of the storage disk, an electromechanical actuator mechanism for positioning the data transducer head relative to the disk, a digital actuator controller means for controlling the actuator mechanism within a closed loop head positioner servo and having internal registers at addressable locations, a memory for storing information read from the disk and for storing at least one trace record, and a memory controller for controlling addressing of the memory. A trace taking process and structure reads at least one of the internal digital registers of the actuator controller during a sampling interval and records a resultant trace value within the trace record of the memory. An on-board analyzer process retrieves and processes the trace record into a correction.