Abstract: A system and method for displaying ranged measurements of objects within an image display is disclosed. Embodiments may use a range finding device to measure distances of objects from a user. Aspects of the subject technology may compensate for tilt of the object and/or of the device capturing the image.

Abstract: Magnetic reference patterns may be generated on a disk or other magnetic media without the need for seed wedges. This involves writing a first magnetic reference pattern to the disk with a servo writer. The disk may then be transferred to a hard disk drive. Control circuitry within the hard disk drive may recognize the first magnetic reference pattern and then position a RW head within the hard disk drive based on the first magnetic reference pattern. As the RW drive is accurately positioned based on the first magnetic reference pattern a second magnetic reference pattern may be written to the disk using the RW head. The RW head location is determined based on the velocity and phase between the read-write head and spiral sync marks contained within the first magnetic reference pattern.

Abstract: A method determines RW head radial position relative to tracks within a magnetic data disc. This involves sensing both a S-burst signal and a P-burst signal with the RW head. The S-burst signal and P-burst signal are associated with a two-burst servo pattern on the magnetic disc. The S-burst pattern has a phase that remains constant radially across tracks within the magnetic disc. The P-burst has a second phase that rotates radially across tracks within the magnetic disc. By determining a phase difference between a sensed S-burst signal and P-burst signal, it is possible to determine the RW head radial position relative to the tracks on the magnetic disc.

Abstract: Magnetic reference patterns may be generated on a disk or other magnetic media without the need for seed wedges. This involves writing a first magnetic reference pattern to the disk with a servo writer. The disk may then be transferred to a hard disk drive. Control circuitry within the hard disk drive may recognize the first magnetic reference pattern and then position a RW head within the hard disk drive based on the first magnetic reference pattern. As the RW drive is accurately positioned based on the first magnetic reference pattern a second magnetic reference pattern may be written to the disk using the RW head. The RW head location is determined based on the velocity and phase between the read-write head and spiral sync marks contained within the first magnetic reference pattern.

Abstract: Magnetic reference patterns may be generated on a disk or other magnetic media without the need for seed wedges. This involves writing a first magnetic reference pattern to the disk with a servo writer. The disk may then be transferred to a hard disk drive. Control circuitry within the hard disk drive may recognize the first magnetic reference pattern and then position a RW head within the hard disk drive based on the first magnetic reference pattern. As the RW drive is accurately positioned based on the first magnetic reference pattern a second magnetic reference pattern may be written to the disk using the RW head. The RW head location is determined based on the velocity and phase between the read-write head and spiral sync marks contained within the first magnetic reference pattern.

Abstract: A method determines RW head radial position relative to tracks within a magnetic data disc. This involves sensing both a S-burst signal and a P-burst signal with the RW head. The S-burst signal and P-burst signal are associated with a two-burst servo pattern on the magnetic disc. The S-burst pattern has a phase that remains constant radially across tracks within the magnetic disc. The P-burst has a second phase that rotates radially across tracks within the magnetic disc. By determining a phase difference between a sensed S-burst signal and P-burst signal, it is possible to determine the RW head radial position relative to the tracks on the magnetic disc.

Abstract: A method determines RW head radial position relative to tracks within a magnetic data disc. This involves sensing both a S-burst signal and a P-burst signal with the RW head. The S-burst signal and P-burst signal are associated with a two-burst servo pattern on the magnetic disc. The S-burst pattern has a phase that remains constant radially across tracks within the magnetic disc. The P-burst has a second phase that rotates radially across tracks within the magnetic disc. By determining a phase difference between a sensed S-burst signal and P-burst signal, it is possible to determine the RW head radial position relative to the tracks on the magnetic disc.

Abstract: The present invention provides a method of generating magnetic reference patterns on a disk or other magnetic media. This involves writing a first magnetic reference pattern to the disk with a servo writer. The disk may then be transferred to a hard disk drive. Control circuitry within the hard disk drive may recognize the first magnetic reference pattern and then position a RW head within the hard disk drive based on the first magnetic reference pattern. As the RW drive is accurately positioned based on the first magnetic reference pattern a second magnetic reference pattern may be written to the disk using the RW head. The RW head location is determined based on the velocity and phase between the read-write head and servo setter marks contained within the first magnetic reference pattern.

Abstract: A disk drive selectively provides either higher-performance seek operations or reduced-audible noise while effecting seek operations. A higher performance seek operating mode and a quiet seek operating mode are defined. The servo controller controls seek operations and may store and/or access a number of seek profiles including a first seek profile defined to provide relatively short average seek times and a second seek profile defined to provide quieter operation on average in comparison with the first seek profile. The servo controller and associated circuitry causes the drive to effect a seek operation subject to the first seek profile in response to the higher performance seek operating mode and effect a seek subject to the second seek profile in response to the quiet seek operating mode.

Abstract: A disk drive implements a technique for improving data storage capacity of data tracks having a servo wedge defect. A servo-fault position threshold is established for aborting a write operation if a transducer head position error from a circular track centerline exceeds the servo-fault position threshold. Servo wedges having operation, the servo-fault position threshold is ignored at a tagged servo wedge thereby preventing the tagged servo wedge from aborting a write operation. The data write operation is prevented for a predetermined number of servo wedges immediately following the tagged servo wedge by skipping data wedges between the tagged servo wedge and a last servo wedge of the predetermined number of servo wedges. Data may be written to a data wedge immediately following the last servo wedge.

Abstract: Disclosed is a disk drive having a plant with a moveable transducer and a servo controller that more precisely controls the transducer during short to medium seeks by producing a multi-rate feed-forward command effort signal.

Abstract: A method of operating a disk drive to efficiently recover from an event which interrupts a safe-to-write condition that occurs during a write operation includes receiving a string of data blocks for writing on respective addressable locations on a track of a disk in the disk drive. During a pass of the addressable locations under the read/write head, the head is positioned to follow the track within a tolerance limit and a first write operation is started to write the string of data blocks on the track. During the first write operation, if it is detected that a safe-to-write condition no longer exists, as may be triggered by a shock event, the first write operation is aborted. When it is later determined that the safe-to-write condition is asserted, a second write operation is defined to write a set of addressable locations within the string of data blocks which have yet to pass under the read/write head and the second write operation is performed.

Abstract: A disk drive having multi-burst servo wedges and single-burst servo wedges for improving shock performance with less impact on data space than otherwise possible and a method of increasing the servo sampling rate for effecting reasonable shock detection in such a disk drive using such multi-burst and single-burst servo wedges. The additional single-burst servo wedges may contain certain desired servo wedge fields, or may consist of just the servo burst itself. In operation, the multi-burst and single servo wedges are processed in series. The multi-burst servo wedge is read to develop a position error signal and control the head, and the single-burst servo wedge is read, the single burst amplitude is compared to one of the plurality of burst amplitudes and, if the single burst amplitude differs by more than a predetermined threshold amount from the one previous burst amplitudes, the system aborts a data write operation.

Abstract: A method in a magnetic storage disk drive for independently learning and thereafter canceling repeatable runout that is written to the servo fields of each servo track during the servo writing process. The method does not require a servo writer because the disk drive may independently detect the runout without spinning out of control in response to such runout by operating its servo control loop in a low bandwidth mode so that it is less responsive to the higher frequency components of the runout, and by removing the effect of the DC component of the runout or selected harmonics on each revolution.

Abstract: A disk drive with a disk having a servo pattern including a special “calibration track” wherein a plurality of staggered calibration burst pairs define null points that are radially shifted from a burst pair centerline by precise, predefined, fractional track amounts to collectively provide accurate information about servo signal values generated as a function of real displacement. The staggered calibration bursts beneficially allows for calibrating the PES signal after the drive is removed from the servowriter during a manufacturing phase called Intelligent Burn-In. The staggered calibration bursts are preferably written in data regions so that they are disposable and may be selectively written over with data to maximize storage space. Some or all of the calibration bursts may alternatively be retained for a subsequent recalibration.

Abstract: A method in a magnetic storage disk drive for independently learning and thereafter canceling repeatable runout that is written to the servo fields of each servo track during the servo writing process. The method does not require a servo writer because the disk drive may independently detect the runout without spinning out of control in response to such runout by operating its servo control loop in a low bandwidth mode so that it is less responsive to the higher frequency components of the runout, and by removing the effect of the DC component of the runout or selected harmonics on each revolution.The method takes several revolutions to "learn" the servo wedges of a current track by initializing a wedge runout value for each servo wedge and an average uncorrected runout value and then successively developing an interim wedge runout estimate for each servo wedge by adding a fractional portion .lambda. of a raw position error signal to a fractional portion (1-.lambda.

Abstract: A method used to implement a sampled servo control system in a magnetic disk drive for generating a fractional track portion of a position error signal to correctably maintain the alignment of a read transducer (or associated write transducer) relative to a centerline of one of a plurality of a concentric data tracks upon a rotating data storage disk. The system uses a hybrid approach of determining a fractional track position by using a two-burst algorithm when possible and using a multi-burst algorithm only when necessary. The system is particularly suited to determining fraction track position when jogging a relatively narrow magnetoresistive read transducer with a servo pattern normally useful only for wider transducers, namely a pattern of four angularly sequential servo bursts A, B, C, D that are 100% of a track pitch in width and are arranged in quadrature.

Abstract: A magnetic storage disk drive having a servo burst pattern which asymmetrically increases the linear region in which a read head may be micro-jogged from a burst pair center line to align the read head with a data track. The innovative servo pattern comprises a first pair of servo bursts that define a first burst pair centerline for writing a particular data track to a data track side of the first centerline, and a second pair of servo bursts collectively define a second burst pair centerline that is positioned to the data track side of the first burst pair centerline and is sufficiently close to the first burst pair center line so that the read head "sees" the second pair of servo bursts before "losing" the first pair of servo bursts when micro-jogged to the data track side for reading. The second burst pair centerline should be no farther from the first burst pair centerline than the linear read width of the read head.

Abstract: The invention is a method of calibrating a position error signal (PES) to overcome the problem of a measured displacement or PES that varies as a non-linear function of real displacement when the read transducer is positioned to either side of a null position where the PES equals zero. The PES is notably nonlinear while reading servo burst information with a Magneto-Resistive (MR) head which has nonlinear magnetic characteristics. The method uniquely calibrates the measured PES to provide a corrected PES without requiring any knowledge of the actual displacement from the position where the measured PES equals 0. The calibration according to this method, therefore, may be performed at anytime without need for real displacement information from a servowriter or any sort of special calibration track.

Abstract: The invention relates generally to rotating magnetic storage disk drive and, more particularly, to a method of seamlessly recording circumferentially overlapping servo bursts on a magnetic disk with successive passes of a write head that is guided by a servo track writer wherein the servo bursts are contained in at least two servo burst groups that each have at least one circumferential burst position which may contain a servo burst.