Seagate Technology Incorporated

Brian W Sudman

Kent J Forbord

John S Putnam

Robert J Nielsen

Mark A Gaertner

Dallas W Meyer

Alexei Hiram Sacks

Monty Aaron Forehand

Reed David Hanson

Lealon Ray McKenzie

Michael Edward Baum

James H McGlennen

Brian Robert Pollock

Mukund Channagiri Rao

Dennis D Duffy

Krishna Rameshwara Malakapalli

Joseph S Stoutenburgh

William C Little

Todd Phillip Fracek

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

One embodiment of the present invention is directed to a method of aligning servo wedges of a plurality of disc surfaces in a disc drive. This process of aligning servo wedges in a disc drive includes writing multiple servo wedges, one adjacent another, continuously across an entire circumference of each disc surface. Subsequently, one of the disc surfaces is designated the master surface. Every n servo wedge on the master surface is then designated as a master wedge, where n is a positive integer. Next, the servo wedges on the non-master surfaces which are most closely axially aligned with the master wedges are selected. Subsequently, all of the non-selected and non-master wedges are erased.

Method of aligning servo wedges in a disc drive

An electrical circuit package including disk drive operation and control circuitry is formed in multiple layers, including a compliant circuitry layer coextensive with the package, and additional conductive and dielectric layers to form relatively stiff circuit panels bonded to the compliant layer and spaced apart from one another. Portions of the compliant layer, between confronting edges of adjacent circuit panels, provide compliant joinder segments. Each joinder segment electrically couples its associated pair of circuit panels, and structurally couples the panels in a manner that permits a selective, non-coplanar orientation of the panels relative to each other. Thus, the panels are electrically and structurally coupled in a manner that facilitates testing the circuit package as a single unit, followed by installation of the package to a disk drive housing with the circuit panels integral with the housing and in the desired non-coplanar arrangement. The non-coplanar arrangement increases area available for supporting semiconductor components. Selectively arranging the components over the available panel surface area facilitates heat dissipation. Selective shaping and positioning of the panels about the housing enables the housing to accommodate full height actuator and spindle motors.

Disk drive housing with recess for circuit panel

A magnetic disc storage system includes a magnetic storage disc and a transducing head. During periods of inactivity the transducing head is dithered whereby the head is moved to tracks on the disc according to a number of criteria. The criteria includes wear reduction, power reduction, avoidance of textured zones, head cycling, increased fly height and clearing of debris carried on the head.

Head positioning in storage system during periods of inactivity

Unitary rigid and flexible circuit package for disk drives

Growing community of inventors

Eden Prairie, MN, United States of America

Brian W Sudman