Narayanan Ramakrishnan

US Patent:

7889627, Feb 15, 2011

Filed:

Nov 5, 2007

Appl. No.:

11/935003

Inventors:

Narayanan Ramakrishnan - Pittsburgh PA, US
Patrick Beckrow Chu - Wexford PA, US
Mark David Bedillion - Allison Park PA, US

Assignee:

Seagate Technology LLC - Scotts Valley CA

International Classification:

G11B 9/00

US Classification:

369126, 977947

Abstract:

An apparatus includes a data storage media and a plurality of heads, the data storage media and heads being structured and arranged for relative movement between the heads and storage media causing the heads to move along a scan path, and an actuator for changing a magnitude of head to media force as the heads move along the scan path. A method for reducing head motion hysteresis is also provided.

US Patent:

7948337, May 24, 2011

Filed:

May 31, 2007

Appl. No.:

11/755812

Inventors:

Patrick Breckow Chu - Wexford PA, US
Narayanan Ramakrishnan - Pittsburgh PA, US
Mark David Bedillion - Allison Park PA, US

Assignee:

Seagate Technology LLC - Scotts Valley CA

International Classification:

H01H 51/22

US Classification:

335 78

Abstract:

An apparatus includes a movable member, and first and second actuators coupled to the movable member at positions offset from a first axis that passes through a centroid of the movable member. A controller independently controls the first and second actuators to exert a first force on the movable member in a direction generally parallel to the first axis, thereby controlling both linear and rotational orientation of the movable member. The apparatus can further include third and fourth actuators coupled to the movable member at positions offset from a second axis that passes through the centroid of the movable member, and the controller can independently controlling third and fourth actuators.

US Patent:

7983138, Jul 19, 2011

Filed:

Nov 30, 2006

Appl. No.:

11/606528

Inventors:

Mark David Bedillion - Allison Park PA, US
Patrick Breckow Chu - Wexford PA, US
Narayanan Ramakrishnan - Pittsburgh PA, US
James Dillon Kiely - Sewickley PA, US
Gudrun Ghilaine Agnes De Gersem - Pittsburgh PA, US

Assignee:

Seagate Technology LLC - Scotts Valley CA

International Classification:

G11B 9/00
G11B 11/00

US Classification:

3692581, 3602461, 369126

Abstract:

An apparatus comprises a storage medium, a substrate separated from the storage medium by a gap, and a plurality of spacers defining a distance between the storage medium and the substrate, wherein the spacers include a curved end.

US Patent:

20130152695, Jun 20, 2013

Filed:

Dec 15, 2011

Appl. No.:

13/326575

Inventors:

Narayanan Ramakrishnan - Bloomington MN, US
Stefan Alexander Weissner - St. Louis Park MN, US

Assignee:

SEAGATE TECHNOLOGY LLC - CUPERTINO CA

International Classification:

G01B 7/16

US Classification:

73774

Abstract:

In certain embodiments, an apparatus includes a first piezoelectric (PZT) element poled in the same direction as a second PZT element. The first and second PZT elements are configured to be driven while simultaneously sensing motion. The apparatus further includes a circuit configured to add outputs of the first and second PZT elements, extract the sensed motion, and detect off-track motion from the extracted sensed motion.

US Patent:

20140022672, Jan 23, 2014

Filed:

Jul 19, 2012

Appl. No.:

13/553072

Inventors:

Narayanan Ramakrishnan - Bloomington MN, US
Ajaykumar Rajasekharan - Bloomington MN, US

Assignee:

SEAGATE TECHNOLOGY LLC - Cupertino CA

International Classification:

G11B 5/60

US Classification:

3602354, G9B 5229

Abstract:

In certain embodiments, a slider includes an air bearing surface having a cavity. The cavity includes transition features at an upstream side of the cavity to mitigate air flow expansion along the cavity. Turbulence-inducing features are positioned on the transition features.

US Patent:

7787213, Aug 31, 2010

Filed:

Dec 7, 2006

Appl. No.:

11/608017

Inventors:

A. David L. Michael - Auburndale MA, US
Ed Acciardi - Grafton MA, US
Narayanan Ramakrishnan - Pittsburgh PA, US

Assignee:

Maxtor Corporation - Longmont CO

International Classification:

G11B 33/02
G11B 33/14

US Classification:

360 9703

Abstract:

A flow control plate () for a disk drive is disclosed. The flow control plate () includes both a diffuser section () and an air displacement section (). The diffuser section () is contained within a pocket () having a plurality of spaced protuberances or ridges (). The air displacement section () may be located upstream of the diffuser section () and includes a pair of flat primary surfaces () that are disposed in opposing and parallel relation. In one embodiment, the flow control plate () is an integral structure and is fabricated from a resinous material.

US Patent:

20200211589, Jul 2, 2020

Filed:

Mar 10, 2020

Appl. No.:

16/814028

Inventors:

- Cupertino CA, US
Narayanan Ramakrishnan - New City NY, US

International Classification:

G11B 5/60
H02N 2/08

Abstract:

A method includes producing a first surface acoustic wave (SAW) on a magnetic head slider using a first interdigitated transducer (IDT), wherein the SAW has a first set of wave characteristics. The method also includes receiving the first SAW at a second IDT on the magnetic head slider. The method also includes analyzing the SAW for a second set of wave characteristics. The method also includes determining, based on the analyzing, that a substance having at least one characteristic is located in a path of the SAW on the magnetic head slider.

US Patent:

20190325904, Oct 24, 2019

Filed:

Mar 29, 2019

Appl. No.:

16/369297

Inventors:

- Cupertino CA, US
Narayanan Ramakrishnan - New City NY, US

International Classification:

G11B 5/60
H02N 2/08

Abstract:

A method includes producing a first surface acoustic wave (SAW) on a magnetic head slider using a first interdigitated transducer (IDT), wherein the SAW has a first set of wave characteristics. The method also includes receiving the first SAW at a second IDT on the magnetic head slider. The method also includes analyzing the SAW for a second set of wave characteristics. The method also includes determining, based on the analyzing, that a substance having at least one characteristic is located in a path of the SAW on the magnetic head slider.