Maxtor Corporation

Seagate Technology Incorporated

Stan Shepherd

Yu Sun

Lin Guo

S Craig Smith

Xin Yang

Craig Smith

Bruce A Liikanen

Yuan Chen

Brian P Rigney

Nathan Hays

Tim Everett

Todd Franks

Erhard Theodor Schreck

Charles R Watt

Don Brunnett

Xiaoping Hu

Peter A McEwen

Bernhard Hiller

Patrick J Moran

Bill Richard Baker

John W Vanlaanen

Jason Adler

Dave McMurtrey

Eduardo Gentile Veiga

Murat Erkocevic

Jay Jeong

Mike Moser

Systems and methods from loading/unloading a data head for a disk drive provide for more efficient use of disk space. A method of loading/unloading a data head for a disk drive comprises determining a disk phase of a spinning disk arrangement, determining a loading/unloading position based on the disk phase, and loading or unloading the data head on or from, respectively, the spinning disk arrangement based on the determined disk phase. The determining a disk phase may be based on zero crossing of voltages for a three-phase motor associated with the spinning disk arrangement.

Disk-synchronized loading/unloading of magnetic head

Embodiments of the present invention allow for media erasure. Various embodiments allow for controlling an actuator based on feedback signal measurements and disk phase to seek a head across a surface of a disk systematically for an erasure operation. Also, in various embodiments, a substantially repeatable seek motion of a head across a stroke may be determined, and launch points at which the head is launched over a disk in the seek motion for erasing at least a portion of the disk are determined based on disk phase.

Angularly spaced spiral erase for media

Devices and methods for performing dynamic sampling of a back electromotive force (BEMF) measurement are provided. A device has hardware, including a voice coil motor (VCM) for receiving a VCM command signal and a correction circuit, for obtaining the VCM command signal and a coil voltage measurement from the hardware, where the correction circuit removes a transient voltage measurement due to a change in the VCM command signal from the coil voltage measurement and outputs an estimated BEMF measurement.

Methods and apparatuses for measuring VCM BEMF at a VCM control update rate

An apparatus and method for servo writing are disclosed. The method includes writing of first servo data to a medium, detecting a velocity integrated position of the first servo data, and writing second servo data in relation to the detected position of the first servo data.

Self-servo writing using staged patterning

The present invention is directed to a method and apparatus for providing an absolute reference point on a disk surface of a disk drive. A write head associated with the disk surface is used to write spirals of servo information thereon, for example, under control of a servo track writer. The spirals of servo information include standard spirals and special spirals. In one embodiment, the special spirals are shorter than the standard spirals and the special spirals are rotationally non-symmetric. For example, an unequal number of standard spirals are interposed between one pair of adjacent special spirals relative to the number of standard spirals interposed between other pairs of adjacent special spirals. The special spirals may take a variety of other forms to distinguish themselves from standard spirals.

Spiral servo patterns with absolute reference point

In accordance with various embodiments, a rotatable member is mounted to a spindle hub so that initial servo data previously provided to the rotatable member are eccentrically offset with respect to a rotational center of the spindle hub. Compensation vales are determined to characterize said offset, after which final servo data are provided to the rotatable member in relation to the initial servo data and the determined compensation values. The final servo data are nominally concentric with the rotational center of the spindle hub.

Servo writing with offset compensation for prewritten reference

In accordance with various embodiments, initial servo data are written to a storage medium as a series of radially overlapped spiral segments. Final servo data are thereafter written to the medium while concurrently servoing on said overlapped segments.

Servo writing using radially overlapped servo segments

A disk drive includes a head and a disk, spiral patterns are located on the disk, and the disk drive self-writes servo patterns on the disk using the spiral patterns as a reference for servoing the head. In an embodiment, the disk drive uses preliminary servo patterns to determine repeatable runout of the spiral patterns. In another embodiment, the disk drive reads each spiral pattern with multiple timing windows.

Method of self-servo writing in a disk drive using multiple timing windows

An apparatus and associated method for preconditioning an elastomeric stop member to create a stabilized reference position for a moveable member by repetitively biasing the moveable member against the stop member and using the stabilized reference position to initiate a writing of servo data by the moveable member to a storage surface.

Preconditioning an elastomeric stop member for use as a reference position

Methods of compensating for repeatable runout in a disk drive are provided. The disk drive includes a data storage disk, a transducer adjacent to the disk, a primary actuator for positioning the transducer over a first range of movement, and a secondary actuator for positioning the transducer over a second range of movement that is less than the first range of movement. Estimates are made of the position of the secondary actuator in the second range of movement. Data is read from the disk via the transducer. A position error signal is determined based on the read data. Positioning of the transducer by the primary actuator is controlled based on the estimated position of the secondary actuator in the second range of movement and based on the position error signal to compensate for repeatable runout.

Multi-stage actuator disk drives, methods, and computer program products that compensate for repeatable runout based on estimated secondary actuator position

Method of self-servo writing in a disk drive using a spiral pattern

A method and system for self-servo writing a disk drive by transferring a servo reference pattern by magnetic printing onto at least one storage surface of a reference disk, wherein a resulting printed reference pattern includes embedded servo information providing servo timing and transducer head position information; assembling the disk drive including the steps of installing at least said disk into the disk drive and enclosing said disk and the data transducers within a housing sealed against particulate contamination from an eternal ambient environment; reading the printed reference pattern from said disk via at least one transducer head to generate a readback signal; sampling the readback signal at a sampling rate to generate a sampled signal; processing the sampled signal waveform specturm to generate a recovered signal including the embedded servo information and a fundamental frequency of the sampled signal; using the servo information from the recovered signal to precisely position and maintain the data transducers at concentric track locations of disk storage surfaces; and self-writing disk drive servo patterns onto the storage surfaces at the concentric track locations with the data transducers in accordance with disk drive servo pattern features.

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Morgan Hill, CA, United States of America

Stan Shepherd