A disk drive is disclosed comprising a voice coil motor (VCM) for rotating an actuator arm about a pivot in order to actuate a head over a disk. The disk is rotated by a spindle motor, and a feed-forward compensation value is computed that compensate for a non-centric alignment of the disk with respect to the spindle motor. During a calibration mode, the VCM is controlled to press the actuator arm against a crash stop, and the feed-forward compensation value is computed in response to a position error signal (PES). The PES is generated in response to embedded servo sectors recorded on the disk, wherein each embedded servo sector comprises a track address for coarse alignment and servo bursts for fine alignment.

Disk drive computing repeatable run out while actuator arm is pressed against crash stop

An ultrasound system is provided which includes a therapy ultrasound transducer and a diagnostic ultrasound transducer and operates in accordance with a method to direct the application of the therapy ultrasound. The method includes operating the diagnostic ultrasound transducer to acquire a first ultrasound image; simultaneously operating the diagnostic ultrasound transducer and therapy ultrasound transducer for a second interval to acquire a second ultrasound image; and determining a difference in the first and second images indicative of the pattern of the therapy ultrasound transducer signal. The difference in the images, which result from enhanced non-linearities and propagation distortions induced by the high intensity therapy ultrasound, can be obtained by subtracting the two images. A method is also provided for monitoring the progress of high intensity therapy ultrasound which evaluates transient changes due to in-situ heating as well as permanent changes which result from cell microstructure alteration.

System and method for ultrasonic harmonic imaging for therapy guidance and monitoring

A disk drive comprising a moveable head, a disk, and a servo controller that implements servo control techniques to preserve PES continuity during track following operations is disclosed. The disk includes a plurality of tracks in which a substantial majority of the tracks include a plurality of servo sectors having a plurality of servo bursts that are utilized in track following operations. The servo controller controls track following operations with the moveable head and implements operations to preserve PES continuity during track following. These operations include: dividing tracks of the disk into a plurality of zones wherein each zone includes zone boundaries; and utilizing a PES equation for each zone to generate a PES value based upon read servo bursts wherein each zone PES equation includes a normalizing factor to account for boundary conditions associated with zone boundaries to preserve PES value continuity between zones.

Disk drive servo control techniques to preserve PES continuity

A method is disclosed for determining fundamental-frequency repeatable runout (1FRRO) coefficients in a disk drive. The disk drive includes a transducer head, a rotating magnetic disk having a plurality of concentric data tracks defined by embedded servo wedges that provide position information, and an actuator coupled to the head. In the method, the head is caused to move in a substantially constant velocity motion across a selected portion of the tracks of the rotating magnetic disk in response to a control signal. The position information is read from the embedded servo wedges as the head moves across of the selected portion of the tracks. The 1FRRO coefficients are determined based on the position information read as the head moved in a substantially constant velocity motion across the selected portion of the tracks.

Method for improved repeatable run out learning in a disk drive

A disk drive is disclosed comprising head actuated over a disk comprising a reference pattern. The head is positioned at a first radial location, a first phase error is measured in response to the reference pattern at the first radial location, and a first repeatable runout (RRO) of the first phase error is measured. The head is positioned at a second radial location, a second phase error is measured in response to the reference pattern at the second radial location, and a second repeatable runout (RRO) of the second phase error is measured. The first and second RROs are processed to estimate an offset r 0 representing a difference between an axial rotation of the disk and an axial rotation of the reference pattern.

Disk drive estimating repeatable runout of reference pattern based on repeatable runout of phase error

A method and apparatus for compensating for repeatable run-out errors in a disc drive is disclosed. The compensation is created by determining transfer function values for a servo loop in the drive as well as a sequence of repeatable run-out values for a portion of a disc. The repeatable run-out values are divided by respective transfer function values to produce compensation values that are inverse transformed to produce time-domain compensation values. These time-domain compensation values are injected into the servo loop to compensate for repeatable run-out errors.

Compensation for repeatable run-out error

A disc drive comprises a drive motor mechanically coupled to a disc and a voice coil motor mechanically coupled to a read/write head on the disc. A power integrated circuit is electrically coupled to the drive motor and the voice coil motor. The power integrated circuit includes an integrated temperature sensor that provides a temperature output. A control circuit receives the temperature output and provides a voice coil motor control output to the power integrated circuit as a function of the temperature output.

Optimizing thermal performance of an integrated circuit in a disc drive

The present invention relates to repeatable runout (RRO) compensation of servo control systems that can be used in disc drives or spin-stands. The RRO relates to eccentricity between servo tracks, which were written onto a disc prior to the installation of the disc into the disc drive or spin-stand, and an axis of rotation of the disc. The present invention compensates the servo control loop by canceling the RRO and controlling a head to follow virtual tracks which are eccentric to the data tracks defined by the servo tracks and concentric with the axis of rotation of the disc.

Virtual tracks for repeatable runout compensation

A data storage system and a method for storing data in a data storage system are provided. The data storage system includes a data storage medium that has at least one physical track that stores at least a portion of manufacturing process data, and virtual tracks that store user data.

Utilizing a combination of physical tracks and virtual tracks to store data on a data storage medium

A method includes acquiring, by a data storage device, signals generated by one or more sensors that relate to a mechanical vibration of the data storage device. The one or more sensors are in electrical communication with the data storage device. The method includes storing a representation of the signals as data in the data storage device.

Vibration analysis methodology using data storage devices

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