James H Mcglennen

6483300, Nov 19, 2002

Dec 5, 2000

09/730182

Gregg J. Severson - Prior Lake MN
James H. McGlennen - Eden Prairie MN
Daniel J. Brown - St. Anthony MN
Thomas S. Rasmussen - Kasson MN

Seagate Technology LLC - Scotts Valley CA

G01R 3312

324212, 360 9703

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.

6510752, Jan 28, 2003

Oct 25, 1999

09/426349

Alexei H. Sacks - Edina MN
James H. McGlennen - Eden Prairie MN
Albert van der Schans - Minnetonka MN

Seagate Technology LLC - Scotts Valley CA

G01N 1900

738659, 73 179, 324210, 324212, 360 75, 360 7805, 360 7812

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.

6538838, Mar 25, 2003

Oct 25, 1999

09/425808

Alexei H. Sacks - Edina MN
James H. McGlennen - Eden Prairie MN
Albert van der Schans - Minnetonka MN

Seagate Technology LLC - Scotts Valley CA

G11B 558

360 7701, 324210, 324212

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.

6952320, Oct 4, 2005

Dec 8, 2000

09/733405

Brian Pollock - Eden Prairie MN, US
Alexei H. Sacks - Edina MN, US
Brian Sudman - Eden Prairie MN, US
James H. McGlennen - Eden Prairie MN, US
Reed D. Hanson - Chaska MN, US

Seagate Technology LLC - Scotts Valley CA

G11B005/596
G11B015/12

360 7704, 360 63

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.

7791831, Sep 7, 2010

Oct 13, 2005

11/249581

James H. McGlennen - Eden Prairie MN, US
Ronald E. Anderson - Lakeville MN, US

Seagate Technology LLC - Scotts Valley CA

G11B 21/04

360 70

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.

8582228, Nov 12, 2013

Feb 10, 2011

13/024887

Ronald E. Anderson - Lakeville MN, US
James H. McGlennen - Eden Prairie MN, US
Brett R. Herdendorf - Mound MN, US

Seagate Technology - Cupertino CA

G11B 21/12
G11B 27/36

360 75, 369 5341

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.

20010048255, Dec 6, 2001

May 25, 2001

09/864361

Gary Sorenson - Eden Prairie MN, US
Thomas Schmitt - Apple Valley MN, US
Klaus Obergfell - Minneapolis MN, US
James McGlennen - Eden Prairie MN, US

H02K011/00

310/071000, 310/06700R

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.

20160254020, Sep 1, 2016

Feb 27, 2015

14/633556

- Cupertino CA, US
Wenzhong Zhu - Apple Valley MN, US
Edward Gage - Lakeville MN, US
James Mcglennen - Eden Prairie MN, US
Jon Trantham - Chanhassen MN, US

G11B 7/1263
G11B 5/596

A data storage device may be configured with at least a heat assisted magnetic recording head that has a laser and is connected to a controller. The heat assisted magnetic recording head can be positioned proximal first and second data bits stored on an adjacent data storage medium. A first laser power may be applied by the laser in response to the first data bit being a different magnetic polarity than the second data bit and a different second laser power can be applied by the laser in response to the first and second data bits having a common magnetic polarity.