Abhishek Dhanda

US Patent:

7916422, Mar 29, 2011

Filed:

May 28, 2010

Appl. No.:

12/790608

Inventors:

Guoxiao Guo - Foothill Ranch CA, US
Abhishek Dhanda - Mission Viejo CA, US
Jie Yu - Irvine CA, US

Assignee:

Western Digital Technologies, Inc. - Irvine CA

International Classification:

G11B 5/596
G11B 5/00

US Classification:

360 7708, 360 76

Abstract:

A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of servo tracks defined by a plurality of servo sectors, wherein each servo sector comprises a plurality of servo bursts, and each servo burst comprises a predetermined phase. After positioning the head over one of the servo tracks, a servo burst in one of the servo sectors is read to generate a read signal, and a sine and cosine component are extracted from the read signal. At least one of the sine and cosine components is rotated by an angle based on a radial location of the head. A position error signal for the head is generated in response to the rotated component.

US Patent:

8531798, Sep 10, 2013

Filed:

Dec 13, 2010

Appl. No.:

12/966474

Inventors:

Wei Xi - Mission Viejo CA, US
Abhishek Dhanda - Mission Viejo CA, US
Guoxiao Guo - Foothill Ranch CA, US
Jie Yu - Irvine CA, US

Assignee:

Western Digital Technologies, Inc. - Irvine CA

International Classification:

G11B 5/596

US Classification:

360 7814, 360 7804, 360 7708

Abstract:

A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of servo sectors that define a plurality of servo tracks, wherein the servo sectors comprise a plurality of servo bursts. A radial velocity of the head is detected relative to the servo tracks. At least two of the servo bursts are read to generate servo burst signals, and the servo burst signals are adjusted in response to the radial velocity of the head. A position error signal is generated for the head in response to the adjusted servo burst signals.

US Patent:

8576506, Nov 5, 2013

Filed:

Jun 21, 2012

Appl. No.:

13/529817

Inventors:

Honge Wang - Irvine CA, US
Michael Chang - San Jose CA, US
Abhishek Dhanda - San Jose CA, US
Huanxiang Ruan - Irvine CA, US
Guoxiao Guo - Irvine CA, US

Assignee:

Western Digital Technologies, Inc. - Irvine CA

International Classification:

G11B 5/09

US Classification:

360 50, 360 51, 360 39, 360 7708

Abstract:

A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of servo sectors defining a plurality of servo tracks. The servo tracks form a plurality of servo zones. A disk locked clock is synchronized relative to a servo data rate of the servo zone the head is over. A first reader/writer gap is measured in cycles of the disk locked clock at a first servo track in the first servo zone. A second reader/writer gap is measured in cycles of the disk locked clock at a second servo track in the second servo zone. The first and second reader/writer gaps are normalized to generate a normalized first and second reader/writer gaps. A third reader/writer gap is estimated in cycles of the disk locked clock at a third servo track in the second servo zone based on the normalized first and second reader/writer gaps.

US Patent:

20130135764, May 30, 2013

Filed:

Nov 29, 2011

Appl. No.:

13/306736

Inventors:

Abhishek Dhanda - San Jose CA, US
Toshiki Hirano - San Jose CA, US
Tetsuo Semba - San Jose CA, US
Zvonimir Z. Bandic - San Jose CA, US

Assignee:

Hitachi Global Storage Technologies Netherlands B.V. - Amsterdam

International Classification:

G11B 27/36

US Classification:

360 31, G9B 27052

Abstract:

A method, apparatus and a data storage device are provided for implementing data track pitch adjustment for data written on a recordable surface of a storage device under operational vibration conditions. An operational vibration disturbance spectrum is detected during a write operation and the data track pitch is selectively adjusted based on the detected operational vibration disturbance spectrum. The adjusted track pitch information is saved and used during a read operation.

US Patent:

20140055883, Feb 27, 2014

Filed:

Aug 24, 2012

Appl. No.:

13/593991

Inventors:

Abhishek Dhanda - San Jose CA, US
Toshiki Hirano - San Jose CA, US
Tetsuo Semba - San Jose CA, US

Assignee:

HGST NETHERLANDS B.V. - Amsterdam

International Classification:

G11B 5/596

US Classification:

360 7708, G9B 5216

Abstract:

A data storage device with improved data storage densities, coupled with lower hard error and write-inhibit events is described. A feed-forward write inhibit (FFWI) method enables data tracks to be written more densely. Alternatively, the FFWI method may reduce the hard error and write inhibit events to improve data storage performance. A concept of virtual tracks enables the FFWI method to be applied to the writing of circular data tracks with non-circular servo tracks, or to the writing of non-circular data tracks with PES data from circular servo tracks—in both cases, improvements to performance and/or storage densities are enabled. The FFWI method may also be applied to the case of both non-circular servo and data tracks.

US Patent:

7898762, Mar 1, 2011

Filed:

Oct 21, 2009

Appl. No.:

12/582863

Inventors:

Guoxiao Guo - Foothill Ranch CA, US
Abhishek Dhanda - Mission Viejo CA, US
Jie Yu - Irvine CA, US

Assignee:

Western Digital Technologies, Inc. - Irvine CA

International Classification:

G11B 5/596

US Classification:

360 7708, 360 31

Abstract:

A disk drive is disclosed comprising a head actuated over a disk, the disk including a plurality of servo sectors wherein each servo sector comprises at least one servo burst. A read signal emanating from the head is sampled while reading a servo burst in a servo sector to generate a plurality of sample values. A quality metric is generated in response to a plurality of sample values of a servo sub-burst representing part of the servo burst. When the quality metric does not exceed a threshold, the servo sub-burst sample values are excluded when generating a position error signal (PES) representing a position of the head over the disk. When the quality metric exceeds the threshold, the servo sub-burst sample values are included when generating the PES. The head is then positioned over the disk in response to the PES.

US Patent:

20230094971, Mar 30, 2023

Filed:

Dec 2, 2022

Appl. No.:

18/061395

Inventors:

- Cupertino CA, US
Abhishek Dhanda - San Ramon CA, US
Gregory Guyomarc'h - San Francisco CA, US
Andrew D. Fernandez - San Jose CA, US
Moshe Laifenfeld - Haifa, IL

Assignee:

Apple Inc. - Cupertino CA

International Classification:

H04N 5/232

Abstract:

Various embodiments disclosed herein include techniques for determining autofocus for a camera on a mobile device. In some instances, depth imaging is used to assist in determining a focus position for the camera through an autofocus process. For example, a determination of depth may be used to determine a focus position for the camera. In another example, the determination of depth may be used to assist another autofocus process.

US Patent:

20180067694, Mar 8, 2018

Filed:

Sep 6, 2016

Appl. No.:

15/257431

Inventors:

- Amsterdam, NL
Abhishek Dhanda - San Jose CA, US
Toshiki Hirano - San Jose CA, US
Satoshi Yamamoto - San Jose CA, US

International Classification:

G06F 3/06

Abstract:

The examples described herein discuss various systems, software, devices, and methods for managing a primary command queue by ordering and/or reordering and distributing incoming commands based, at least in part, on positional information of one or more components of data storage devices. More specifically, in some embodiments, the examples discussed herein describe ordering and distributing incoming commands from a primary command queue in a position-aware manner that takes into account disk rotation (e.g., rotational position) and/or actuator head location for the various data storage devices of a data storage system enclosure. Among other benefits, ordering incoming commands at the primary command queue and distributing the ordered commands to individual device queues improves overall command execution latency.