Maxtor Corporation

Maxtor Corporagion

Tim Everett

Stan Shepherd

Brian P Rigney

Peter A McEwen

Robert L Metz

Patrick J Moran

Bill Richard Baker

John VanLaanen

Eduardo Gentile Veiga

Bill Ray

Howard Barlow

Murat Erkocevic

Jay Jeong

Mike Moser

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

Various embodiments of the present invention are generally directed to processing servo data on a storage surface by detecting a time difference between consecutive read signal envelopes from spiral servo information on the surface.

Acquiring spiral servo information on a storage surface

The present invention is directed to a method and apparatus for reducing velocity errors when writing spiral servo information onto a disk surface of a disk drive. In one embodiment, a servo track writer is provided for moving a write head at a controlled velocity. The write head is used to write spiral servo information onto a disk surface. The write head is moved, using the servo track writer, at an actual velocity trajectory to simulate writing one spiral of spiral servo information. Differences between the actual velocity trajectory and a desired velocity trajectory are measured on a control sample by control sample basis over a window of control samples. The differences are integrated over the window. A gain, associated with the servo track writer controlling the velocity of the write head, is adjusted using the integrated differences.

Method and apparatus for reducing velocity errors when writing spiral servo information onto a disk surface

The present invention is directed to a method and apparatus for improving spiral-based position correction system stability via kernel frequency component modification. In one embodiment, a disk drive includes a disk surface with servo information written thereon, wherein the servo information includes repeatable runout. The disk drive includes a servo system having an error transfer function. Frequencies, where the error transfer function may experience phase changes, are determined and the direction of such phase changes are also determined. A kernel, which is used to calculate position correction values to compensate for repeatable runout, is provided. Phases of frequency components in the kernel, which correspond to the frequencies where the error transfer function may experience phase changes, are rotated.

Method and apparatus for improving spiral-based position correction system stability via kernel frequency component modification

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.

Self-writing of servo patterns in disk drives

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Niwot, CO, United States of America

Tim Everett