Abstract: A data storage device is disclosed comprising a plurality of disk surfaces, a first plurality of heads actuated over a first subset of the disk surfaces by a first actuator, and a second plurality of heads actuated over a second subset of the disk surfaces by a second actuator. A first access command is executed using the first actuator and a second access command is executed using the second actuator. When the first access command finishes before the second access command finishes, a third access command is selected to execute using the first actuator based on a time remaining (To2) to finish the second access command, and at least part of the second access command is executed while concurrently executing at least part of the third access command during To2.

Abstract: A data storage device is disclosed comprising a plurality of disk surfaces, a first plurality of heads actuated over a first subset of the disk surfaces by a first actuator, and a second plurality of heads actuated over a second subset of the disk surfaces by a second actuator. A first access command is executed using the first actuator and a second access command is executed using the second actuator. When the first access command finishes before the second access command finishes, a third access command is selected to execute using the first actuator based on a time remaining (To2) to finish the second access command, and at least part of the second access command is executed while concurrently executing at least part of the third access command during To2.

Abstract: A data storage device is disclosed comprising a plurality of disk surfaces, a first plurality of heads actuated over a first subset of the disk surfaces by a first actuator, and a second plurality of heads actuated over a second subset of the disk surfaces by a second actuator. A first access command is executed using the first actuator and a second access command is executed using the second actuator. When the first access command finishes before the second access command finishes, a third access command is selected to execute using the first actuator based on a time remaining (To2) to finish the second access command, and at least part of the second access command is executed while concurrently executing at least part of the third access command during To2.

Abstract: A data storage device is disclosed wherein an elevator actuator is controlled to move a head along an axial dimension toward a first disk surface of a first disk while processing a proximity signal generated by a proximity sensor. A first actuator position is detected when the actuator arm is proximate the first disk surface of the first disk based on the proximity signal.

Abstract: A data storage device is disclosed wherein an elevator actuator is controlled to move a head along an axial dimension toward a first disk surface of a first disk while processing a proximity signal generated by a proximity sensor. A first actuator position is detected when the actuator arm is proximate the first disk surface of the first disk based on the proximity signal.

Abstract: A data storage device is disclosed comprising a first disk comprising a first disk surface, a second disk comprising a second disk surface, an actuator arm, a head coupled to a distal end of the actuator arm, and a ramp for loading/unloading the head. A first elevator actuator is configured to actuate the actuator arm along an axial dimension relative to the first and second disks, and a second elevator actuator is configured to actuate at least part of the ramp along the axial dimension, wherein a simultaneous movement of the first and second elevator actuators is synchronized.

Abstract: A data storage device is disclosed comprising a first disk comprising a first disk surface, a second disk comprising a second disk surface, an actuator arm, a head coupled to a distal end of the actuator arm, and a ramp for loading/unloading the head. A first elevator actuator is configured to actuate the actuator arm along an axial dimension relative to the first and second disks, and a second elevator actuator is configured to actuate at least part of the ramp along the axial dimension, wherein a simultaneous movement of the first and second elevator actuators is synchronized.

Abstract: A data storage device is disclosed comprising an elevator actuator configured to actuate a head along an axial dimension, and a position sensor configured to generate a sinusoidal sensor signal representing a position of the head along the axial dimension, wherein the position sensor comprises a sensor element and an encoder strip comprising a pattern having at least one region that causes a disturbance in the sinusoidal sensor signal. The elevator actuator is controlled to move the head in a first direction along the axial dimension to detect the disturbance in the sinusoidal sensor signal, and when the disturbance in the sinusoidal signal is detected, the elevator actuator is controlled to move the head in a second direction along the axial dimension opposite the first direction in order to measure a zero crossing of the sinusoidal sensor signal.

Abstract: A data storage device is disclosed comprising a first disk comprising a first disk surface, a second disk comprising a second disk surface, an elevator actuator configured to actuate a head along an axial dimension relative to the first and second disks, a radial actuator configured to actuate the head radially over the first disk surface or the second disk surface, and a position sensor configured to generate a sinusoidal sensor signal representing a position of the head along the axial dimension. A crashstop_offset along the axial dimension is measured from a crashstop position of the elevator actuator to a zero crossing of the sinusoidal sensor signal.

Abstract: An apparatus includes: a media; a head assembly over the media; a head actuation motor coupled to the head assembly; control circuitry, coupled to the head actuation motor, configured to position the head assembly; and a head loading ramp, adjacent to the media; wherein: the control circuitry is further configured to: generate a seek count; and park the head assembly, off of the media, on the head loading ramp, controlling a speed of the head actuation motor based on the seek count.

Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of tracks, wherein each track comprises a plurality of servo sectors. When entering an idle mode, the head is floated over the disk, and when exiting the idle mode, a radial velocity of the head is measured, a seek distance is determined in response to the radial velocity, and a seek operation seeks the head the seek distance to a first track.

Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of tracks, wherein each track comprises a plurality of servo sectors. When entering an idle mode, the head is floated over the disk, and when exiting the idle mode, a radial velocity of the head is measured, a seek distance is determined in response to the radial velocity, and a seek operation seeks the head the seek distance to a first track.

Abstract: A disk drive is disclosed comprising a head actuated over a disk, the disk comprising a plurality of servo sectors defining a plurality of servo tracks, wherein the servo tracks form a plurality of servo zones. A servo data rate of servo sectors in a first servo zone is different than a servo data rate of servo sectors in a second servo zone. A boundary of a first servo zone overlaps with a boundary of a second servo zone over a transition zone. The servo sectors of the first servo zone are interleaved with the servo sectors of the second servo zone within the transition zone. At least one servo parameter is adjusted when the head is over the transition zone in order to transition between the first servo zone and the second servo zone.

Abstract: A method is disclosed for adaptive learning of fundamental-frequency repeatable runout (1FRRO) compensation information in a disk drive. The disk drive includes a transducer head, a magnetic disk having a plurality of concentric data tracks defined by embedded servo wedges that provide position information, and a control system. In the method, 1FRRO compensation information is learned over a predetermined minimum number of disk revolutions. After the predetermined minimum number of disk revolutions, the 1FRRO compensation information is monitored for convergence while learning of the 1FRRO compensation information continues. Learning is terminated upon detection of convergence of the 1FRRO compensation information.

Abstract: Disclosed is a disk drive and method to characterize misaligned servo wedges. The disk drive includes an actuator arm, a head, a disk, and a servo controller. The head is connected to a distal end of the actuator arm in which the actuator arm is rotatable about a pivot to move the head radially over the disk. The servo controller is used to characterize misaligned servo wedges by implementing operations including: commanding the head to track follow on a track; measuring wedge-to-wedge time (WTWT) values corresponding to time intervals between identified servo wedges; calculating wedge-to-wedge time (WTWT) variations for the measured WTWT values; and characterizing the calculated WTWT variations, wherein, characterizing the calculated WTWT variations for the track includes utilizing a WTWT variation modeling function to model the WTWT variations.

Abstract: A disk drive comprising an actuator including a head, a disk, and a processor connected to the actuator by a flex circuit cable. The processor under the control of a program to: apply a control signal for a seek operation and to apply a bias signal to the control signal to approximate the bias imparted by the flex circuit cable. The bias is determined from a data structure that stores: bias values for track zones representative of a first and second bias curves that approximate a bias imparted by the flex circuit cable upon the actuator as the actuator moves the head from the OD to the ID of the disk and from the ID to the OD of the disk, respectively. The bias values representative of the first and second bias curves are determined based upon a non-linear apportionment of track zones.

Abstract: A disk drive is disclosed that estimates a sinusoidal error in a wedge time period due to eccentricity in the disk rotating to generate eccentricity compensation values. During a write operation a head is positioned over a target data sector within a target track, a write clock frequency is set using an eccentricity compensation value corresponding to the target data sector, and data is written to the target data sector using the write clock frequency. In this manner, the eccentricity compensation value adjusts the write clock frequency to better optimize the linear bit density from the inner to outer diameter tracks.

Abstract: Disclosed is a disk drive to characterize misaligned servo wedges. A disk of the disk drive includes a plurality of circumferential tracks, in which, each track includes a plurality of servo wedges spaced sequentially around the circumference of the track wherein the servo wedges may be misaligned relative to the head of the disk drive that moves about a pivot. A servo controller is used to characterize the misaligned servo wedges relative to the head during a seek operation by implementing the following operations: commanding the head to perform a seek operation from a starting track to an ending track; obtaining samples of wedge-to-wedge time (WTWT) values corresponding to time intervals between identified servo wedges for sampled tracks traversed during the seek operation; calculating WTWT variations for each sample; and calculating a calibrated misalignment value for each sample based upon WTWT variations.

Abstract: A disk drive is disclosed comprising a disk having a plurality of servo sectors defining a plurality of servo tracks, wherein each servo sector comprises a track address identifying a corresponding servo track. A head is actuated over the disk, and a ramp is positioned near an outer diameter of the disk, wherein an edge of the ramp extends over a plurality of the servo tracks. The head is loaded from the ramp onto the disk, and a track address in at least one of the servo sectors is detected and stored. The process is repeated a number of times, and then a starting track proximate an outer diameter of the disk is identified in response to the detected and stored track addresses.

Abstract: A disk drive is discloses comprising a disk, a head connected to a distal end of an actuator arm, and a voice coil motor (VCM) for rotating the actuator arm about a pivot in order to actuate the head radially over the disk. If when a power failure occurs the radial location of the head is less than a predetermined distance from the outer diameter of the disk, the VCM is controlled to move the head toward the inner diameter of the disk and stopping the head before it reaches the inner diameter of the disk. The VCM is then controlled to move the head toward the outer diameter of the disk until the actuator arm unloads onto a ramp.