Abstract: A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of tracks. An operating seek time profile is generated as a function of a base seek time profile, wherein the seek time profiles define a seek time to seek the head radially over the disk by a seek length. A seek operation is executed to seek the head by a target seek length by at least generating a target seek time based on the target seek length and the operating seek time profile, and seeking the head the target seek length based on the target seek time.

Abstract: A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of tracks defined by servo sectors, wherein each servo sector comprises a plurality of servo bursts and the servo sectors define a plurality of servo wedges. A first write operation is executed to a first track and a first absolute position for the head is generated corresponding to a first servo wedge. A second write operation is executed to a second track and a second absolute position for the head is generated corresponding to the first servo wedge. An off-track write condition is detected when executing the second write operation based on the first absolute position and the second absolute position. The first absolute position comprises a track address of the first track and a position error measurement based on the servo bursts in the first servo wedge.

Abstract: A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of tracks. An operating seek time profile is generated as a function of a base seek time profile, wherein the seek time profiles define a seek time to seek the head radially over the disk by a seek length. A seek operation is executed to seek the head by a target seek length by at least generating a target seek time based on the target seek length and the operating seek time profile, and seeking the head the target seek length based on the target seek time.

Abstract: A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of tracks, wherein at least two of the tracks comprise a thermal asperity. Prior to seeking the head from a first track to a second track, for each of at least two of the thermal asperities a minimum seek delay and a maximum seek delay that will cause the head to miss the thermal asperity are computed, and an allowed seek delay range that will cause the head to miss the thermal asperity is computed. When the undelayed seek will cause the head to hit at least one thermal asperity, the seek is delayed by a seek delay determined based on the minimum seek delays, the maximum seek delays, and the allowed seek delay ranges.

Abstract: A data storage device is disclosed comprising a disk comprising a plurality of tracks, and an actuator configured to actuate a head over the disk. While seeking the head from a first track toward a second track, a velocity of the head over the disk is measured, and a deceleration distance and a deceleration time is generated based on the measured velocity. A coast velocity is generated based on the measured velocity, the deceleration distance, and the deceleration time, and a control signal applied to the actuator is adjusted based on the measured velocity and the coast velocity.

Abstract: A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of tracks, and a load/unload ramp. When seeking the head a seek length from a starting track to an ending track, control circuit is configured to adjust a seek profile when the seek length is greater than a first threshold and the ending track is within a second threshold of the load/unload ramp.

Abstract: A method of operating a disk drive is disclosed, the disk drive comprising a disk comprising a plurality of tracks, and a closed loop servo system comprising a seek servo loop and a settle servo loop for actuating the head over the disk, the settle servo loop comprising a feed-forward compensator. The seek servo loop seeks the head toward a target track, and when the head approaches the target track a state trajectory of the feed-forward compensator is initialized with an initial value in response to a measured state of the servo system. The settle servo loop then settles the head on the target track in response to a feed-forward compensation generated by the feed-forward compensator.

Abstract: A disk drive is disclosed comprising a disk comprising a plurality of servo tracks, wherein each servo track comprises a plurality of servo sectors, and an actuator for actuating a head over the disk in response to an actuator control signal. The servo sectors are read to generate a first sequence of control samples x[k] at a sample frequency corresponding to a frequency of the servo sectors. A hybrid upsample filter is used to upsample by a factor of N the first sequence of control samples x[k] to generate a second sequence of control samples y[ki], wherein the hybrid upsample filter provides a higher phase gain than a zero-order type upsample filter at frequencies less than one kilohertz, and approximately the same attenuation as a first-order type upsample filter around the sample frequency. The actuator control signal is generated in response to the second sequence of control samples y[ki].

Abstract: A disk drive is disclosed comprising a disk comprising tracks defined by servo sectors, a head, and control circuitry comprising a servo control system operable to actuate the head over the disk in response to the servo sectors. The head is loaded over the disk during a load operation, and a radial velocity of the head is determined during the load operation. A target track is generated based on the determined radial velocity of the head, and the servo control system seeks the head to the target 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 data storage device is disclosed comprising a disk comprising a plurality of tracks defined by servo sectors, a head, and a servo controller configured to servo the head over the disk based on an estimated state generated by a state estimator. The servo controller is configured to execute a seek operation to seek the head over the disk and recover from a servo fault during the seek operation by generating an initial state estimate of the head at the beginning of the servo fault, and decelerating the head open-loop using a model-based deceleration control in response to the initial state estimate. While decelerating the head, the state estimator is re-qualified before the head reaches zero velocity, and after re-qualifying the state estimator and before the head reaches zero velocity, a seek operation is executed to seek the head to a target track closed-loop using the state estimator.

Abstract: A method of operating a disk drive is disclosed wherein the disk drive comprises a disk comprising a plurality of tracks, a head, and a closed loop servo system comprising a seek servo loop and a settle servo loop for actuating the head over the disk. When the head approaches a target track during a seek operation, the settle servo loop is enabled wherein a feedback control signal is generated based on a measured state of the servo system. The feedback control signal is adjusted with a feed-forward compensation. A phase shift between the measured state of the servo system and a corresponding estimated state of the servo system is compensated. The head is settled on the target track in response to the feed-forward compensation.

Abstract: A disk drive is disclosed wherein N data wedges of write data are buffered in a buffer. After writing at least two of the data wedges to the disk including a first data wedge and a second data wedge, a first servo metric value is measured when reading a first servo sector, and a second servo metric value is predicted based on the first servo metric value, wherein the second servo metric value corresponds to a second servo sector following the first servo sector. When the first servo metric value indicates a safe write condition and the second servo metric value indicates an unsafe write condition, the first data wedge is released from the buffer, and when the first servo metric value indicates a safe write condition and the second servo metric value indicates a safe write condition, the first and second data wedges are released from the buffer.

Abstract: A disk drive is disclosed comprising a head actuated over a disk, and control circuitry including a vibration sensor. A position error signal (PES) is generated representing a radial location of the head over the disk, and the head is servoed radially over the disk in response to the PES. A first vibration signal is generated in response to the vibration sensor, and a second vibration signal in response to the PES. The first vibration signal is combined with the second vibration signal to generate a third vibration signal, and a vibration event is detected in response to the third vibration signal.

Abstract: A data storage device is disclosed comprising a disk comprising a plurality of tracks, a head, and an actuator configured to actuate the head over the disk. An adjusted seek time is determined to seek the head from a first track to a second track, and an adjusted coast velocity and an adjusted coast time of the seek is determined based on the adjusted seek time and a power consumption of the seek when a driving current applied to the actuator is substantially constant during at least one of an acceleration time and a deceleration time of the seek.

Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of tracks, and control circuitry operable to seek the head to a target track and settle the head on the target track during a settle time, adapt a settle parameter over an adapting delay of the settle time, wherein the settle parameter is used to settle the head on the target track, and decrease the adapting delay based on a speed that the settle parameter adapts.

Abstract: A disk drive is disclosed wherein a radial offset is measured between a first head and a second head at a plurality of points along a circumference of a corresponding first and second disk surface to generate a first plurality of radial offsets. A first radial offset is determined and a second radial offset is determined based on the first plurality of radial offsets, wherein the first radial offset corresponds to approximately a maximum in the first plurality of radial offsets and the second radial offset corresponds to approximately a minimum in the first plurality of radial offsets. A plurality of access commands are stored in a command queue, and a rotational position optimization (RPO) algorithm is executed to select a next access command to execute from the command queue, wherein the RPO algorithm is responsive to the first and second radial offsets.

Abstract: A disk drive is disclosed comprising a disk comprising a plurality of tracks, a head attached to a distal end of an actuator arm, and a voice coil motor (VCM) operable to rotate the actuator arm about a pivot bearing including a race and a plurality of ball bearings. The VCM is controlled to execute a first jerk seek in a first radial direction so that the ball bearings slip within the race by a first rotation angle. The VCM is controlled to execute a second jerk seek in the first radial direction so that the ball bearings slip within the race by a second rotation angle, wherein the second rotation angle adds to the first rotation angle in order to rotate the ball bearings relative to the race at a reference angle of the pivot bearing.

Abstract: A method or apparatus for changing a performance level of a disk drive from an initial performance level to a target performance level, wherein the disk drive includes a profile table. The method including determining an initial performance level, determining a target performance level, determining constant offset values that cause the performance level of the disk drive to match the target performance level, and programming a constant offset table of the profile table with the constant offset values.

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.