Seagate Technology Incorporated

James H McGlennen

Alexei Hiram Sacks

Albert Van Der Schans

Ronald Eldon Anderson

Gregg Jon Severson

Thomas S Rasmussen

Riyan Alex Mendonsa

Brett Robert Herdendorf

Reed David Hanson

Pu-Ling Lu

Brian Robert Pollock

Patrick J Korkowski

Klaus Obergfell

Brian W Sudman

Thomas J Schmitt

Daniel John Brown

Gary D Sorenson

Douglas A Saunders

Waleed A Farahat

Steven C Ehret

Pradeep K Subrahamanyan

Bits are written to a track of a heat-assisted magnetic recording medium via a write transducer at a first skew angle. The track is read via a read transducer oriented at a second skew angle different from the first skew angle. The second skew angle causes the read transducer be more closely aligned with boundaries of the bits than if oriented at the first skew angle.

Reading and writing to a HAMR recording medium at different skew angles

A locking media pusher is coupled to a servo controlled stage and includes a protruding probe and a locking mechanism. The stage moves forward and backward along a base toward and away from a storage medium. If an eccentricity of a track on the storage medium exceeds a threshold, the storage medium is rotated to an orientation where the greatest eccentricity is directed toward the media pusher. The media pusher is moved toward the storage medium until a probe extending from the media pusher contacts the storage medium. The probe is locked within the media pusher. The stage and attached media pusher are retracted from the storage medium and the storage medium is unlocked. The magnitude of retraction of the stage is recorded. The stage is moved toward the storage medium a distance corresponding to the probe contact position plus the eccentricity magnitude to correct the eccentricity.

Locking media pusher

The invention is directed to methods and apparatus for repositioning a data storage disc on a spindle assembly, to reduce eccentricity of data on the disc. The eccentricity can be identified and be reduced automatically by determining the magnitude and direction of an eccentricity vector that representing a misalignment of a central point around which the data are arranged on a data storage disk with an axis of a spindle, and moving the disc so that the eccentricity vector is reduced. One technique for moving the disc is to push the edge of the disc so that the central point moves closer to the axis of the spindle.

Data storage disc track centering

A high bandwidth, large stroke spin-stand for testing components of a disc drive includes a coarse positioning stage and a rotary micropositioning stage. The spin-stand is capable of positioning a transducer head relative to the data storage disc based on one or both of: (1) an angular position of a rotary actuator arm in the rotary micropositioning stage; and (2) servo data read from the data storage disc. The angular position of the rotary actuator arm is detected by an encoder. In one embodiment, position adjustments are based on the detected angular position. In another embodiment, position adjustments are based on servo data read from the data storage disc, but are also conditional on angular position being consistent with the servo data. In yet another embodiment, both angular position and servo data from a track are linearized to generate PES adjustment parameters that are recorded on the data storage disc to redefine the track as more circular or to linearize the PES.

High bandwidth large stroke spin-stand

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 method and apparatus are provided for testing a head to be used in a disc drive. The method is performed in a spin-stand and includes steps of positioning a head over a radial position on a disc, reading test data from a track at the radial position, reading servo data from the track, and using the servo data to position the head at a desired location within the track. The apparatus for practicing this method includes a disc capable of spinning, a positioning system capable of establishing a position for a head relative to the disc, a servo circuit capable of converting a servo signal into a position value, and a feedback circuit capable of controlling the positioning system based on the position value.

Method and apparatus for closed-loop spin-stand testing

A method and apparatus are provided for testing a microactuator that forms part of a suspension assembly in a disc drive. The method and apparatus test the microactuator before placing the suspension assembly in a disc drive. In the invention, the head is positioned over a track on a disc based in part on servo information read from the disc. At least one input signal is then applied to at last one microactuator on the suspension assembly. Servo information is then read from the disc to determine a change in the position of the head. By comparing the change in the position of the head to the input signal applied to the microactuator, a performance characteristic of a microactuator can be determined.

Method and apparatus for testing microactuators on a suspension assembly

The present invention is directed to a disc heater for use with a spin-stand. The disc heater is adapted to heat a disc that is mounted to a spindle of the spin-stand. The disc heater includes a heater support, a heater, and a controller. The heater support is couplable adjacent the spindle and the disc and is adapted to support the heater near a surface of the disc. The heater produces heat that raises at least a surface of the disc to a temperature that simulates an operating temperature of a disc drive. The controller is electrically coupled to the heater and controls the heat produced by the heater. The spin-stand is adapted to perform various tests on the transducing head. Additional tests, such as accelerated aging studies, can also be performed on the disc.

Spin-stand having a disc heater

A retractable grounding device for a spindle motor having a rotor shaft is provided. The retractable grounding device includes a grounding connector configured to connect the rotor shaft to ground and a position adjuster coupled to the grounding connector. The position adjuster moves the grounding connector between a first position where the grounding connector is in contact with the rotor shaft and a second position where the grounding connector is retracted from the rotor shaft. In addition, a method of selectively grounding a rotor shaft of a spindle motor is provided.

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Eden Prairie, MN, United States of America

James H McGlennen