Chun Yi Tsai from Santa Clara, CA, age 58

Us Patents

Disk Drive Identifying Starting Track By Performing Multiple Load Operations
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US Patent:

7209310, Apr 24, 2007
Filed:

Jul 25, 2005
Appl. No.:

11/188947
Inventors:

Chun Sei Tsai - Tustin CA, US
Ngoc Le - Fountain Valley CA, US
Jenghung Chen - Cupertino CA, US
Hien Chu - Santa Ana CA, US
Assignee:

Western Digital Technologies, Inc. - Lake Forest CA
International Classification:

G11B 21/02
US Classification:

360 75, 360 7808
Abstract:

A disk drive is disclosed comprising a disk having a plurality of servo sectors defining a plurality of servo tracks, wherein each servo sector comprises a track address identifying a corresponding servo track. A head is actuated over the disk, and a ramp is positioned near an outer diameter of the disk, wherein an edge of the ramp extends over a plurality of the servo tracks. The head is loaded from the ramp onto the disk, and a track address in at least one of the servo sectors is detected and stored. The process is repeated a number of times, and then a starting track proximate an outer diameter of the disk is identified in response to the detected and stored track addresses.

Disk Drive To Characterize Misaligned Servo Wedges
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US Patent:

7212374, May 1, 2007
Filed:

Oct 14, 2005
Appl. No.:

11/250649
Inventors:

Zhi Wang - San Jose CA, US
Jenghung Chen - Cupertino CA, US
Chun Sei Tsai - Tustin CA, US
Carl E. Barlow - Lake Forest CA, US
Assignee:

Western Digital Technologies, Inc. - Lake Forest CA
International Classification:

G11B 5/596
G11B 21/02
US Classification:

360 7814, 360 7804
Abstract:

Disclosed is a disk drive to characterize misaligned servo wedges. A disk of the disk drive includes a plurality of circumferential tracks, in which, each track includes a plurality of servo wedges spaced sequentially around the circumference of the track wherein the servo wedges may be misaligned relative to the head of the disk drive that moves about a pivot. A servo controller is used to characterize the misaligned servo wedges relative to the head during a seek operation by implementing the following operations: commanding the head to perform a seek operation from a starting track to an ending track; obtaining samples of wedge-to-wedge time (WTWT) values corresponding to time intervals between identified servo wedges for sampled tracks traversed during the seek operation; calculating WTWT variations for each sample; and calculating a calibrated misalignment value for each sample based upon WTWT variations.

Disk Drive Storing Parameters Of A Write Operation In A Plurality Of Data Sectors
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US Patent:

7933087, Apr 26, 2011
Filed:

Jun 18, 2008
Appl. No.:

12/141693
Inventors:

Chun Sei Tsai - Tustin CA, US
William B. Boyle - Lake Forest CA, US
Carl E. Barlow - Lake Forest CA, US
Assignee:

Western Digital Technologies, Inc. - Irvine CA
International Classification:

G11B 5/09
US Classification:

360 48
Abstract:

A disk drive is disclosed comprising a disk having a plurality of data sectors, and a head actuated over the disk. The disk drive further comprises control circuitry operable to execute a write operation for writing data to the disk. A first part of the data is written to a first data sector together with a first sector signature data (SSD) record comprising a first parameter of the write operation and a first id that identifies the first parameter. A second part of the data is written to a second data sector together with a second SSD record comprising a second parameter of the write operation and a second id that identifies the second parameter.

Disk Drive Biasing Refresh Zone Counters Based On Write Commands
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US Patent:

7974029, Jul 5, 2011
Filed:

Jul 31, 2009
Appl. No.:

12/533950
Inventors:

Chun Sei Tsai - Tustin CA, US
Sang Huynh - Corona CA, US
Anthony L. Pei - Irvine CA, US
Don Brunnett - Pleasanton CA, US
Jahangir John Kasraee - Irvine CA, US
Kent W. Gibbons - Trabuco Canyon CA, US
Assignee:

Western Digital Technologies, Inc. - Irvine CA
International Classification:

G11B 27/36
US Classification:

360 31, 360 48, 360 53, 360 62
Abstract:

A disk drive is disclosed comprising a disk comprising a plurality of tracks, and a head actuated over the disk. A plurality of refresh zones are defined, wherein each refresh zone corresponds to a plurality of the tracks. Data is written to a first refresh zone, and a first zone counter is updated for a second refresh zone at a first rate. Data is written to a third refresh zone, and the first zone counter is updated for the second refresh zone at a second rate different than the first rate.

Disk Drive Employing Different Servo Tpi To Data Tpi Ratios Across The Disk Surface
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US Patent:

7982993, Jul 19, 2011
Filed:

Dec 19, 2008
Appl. No.:

12/340309
Inventors:

Chun Sei Tsai - Tustin CA, US
William B. Boyle - Lake Forest CA, US
Carl E. Barlow - Lake Forest CA, US
Assignee:

Western Digital Technologies, Inc. - Irvine CA
International Classification:

G11B 5/09
G11B 5/596
US Classification:

360 48, 360 7708
Abstract:

A disk drive is disclosed having a first disk surface, and a head actuated over the first disk surface. The first disk surface comprises a plurality of servo tracks and a plurality of data tracks. The data tracks of the first disk surface are banded together into a plurality of data zones, including a first data zone and a second data zone. A first servo tracks per inch (STPI) to data tracks per inch (DTPI) ratio of the first data zone is substantially different from a second STPI to DTPI ratio of the second data zone.

Disk Drive Write Verifying Unformatted Data Sectors
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US Patent:

8004785, Aug 23, 2011
Filed:

May 9, 2008
Appl. No.:

12/118365
Inventors:

Chun Sei Tsai - Tustin CA, US
William B. Boyle - Lake Forest CA, US
Carl E. Barlow - Lake Forest CA, US
Kenneth J. Smith - Corona CA, US
Assignee:

Western Digital Technologies, Inc. - Irvine CA
International Classification:

G11B 5/09
US Classification:

360 53
Abstract:

A disk drive is disclosed comprising a disk having a plurality of data sectors, wherein a physical block address (PBA) is associated with each data sector. When a write command is received from a host to write user data to the disk, and the write command comprises an unformatted logical block address (LBA), the user data is written to a first data sector, and the first data sector is write verified. A second data sector is defect scanned, and after the second data sector passes the defect scan, the user data is migrated from the first data sector to the second data sector and the LBA is formatted to the second data sector.

Disk Drive Generating Actual Data Tpi Profile By Combining Segments Of Predetermined Data Tpi Profiles
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US Patent:

8031423, Oct 4, 2011
Filed:

Jun 26, 2009
Appl. No.:

12/492443
Inventors:

Chun Sei Tsai - Tustin CA, US
Stephany W. Kwan - Rowland Heights CA, US
Kameron Kam-Wai Jung - Yorba Linda CA, US
Assignee:

Western Digital Technologies, Inc. - Irvine CA
International Classification:

G11B 5/09
US Classification:

360 48
Abstract:

A disk drive is disclosed comprising a head actuated over a disk having a plurality of data tracks. An ideal data tracks per inch (TPI) profile is determined for the disk, and an actual data TPI profile is generated that estimates the ideal data TPI profile by combining a first segment of a first predetermined data TPI profile and a second segment of a second predetermined data TPI profile.

Disk Drive Executing Retry Operation After Adjusting Jog Value In Response To Gain Control
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US Patent:

8116025, Feb 14, 2012
Filed:

Dec 18, 2008
Appl. No.:

12/338798
Inventors:

Tom S. Chan - San Marino CA, US
Chun Sei Tsai - Tustin CA, US
Carl E. Barlow - Lake Forest CA, US
Colin W. Morgan - Mission Viejo CA, US
Assignee:

Western Digital Technologies, Inc. - Irvine CA
International Classification:

G11B 5/596
G11B 27/36
US Classification:

360 7706, 360 31, 360 7804
Abstract:

A disk drive is disclosed comprising a disk having a plurality of tracks, wherein each track comprises a plurality of data sectors. A head is actuated radially over the disk for generating a read signal. A first read of a data sector is performed while adjusting an amplitude of the read signal in response to a gain control setting. When an error occurs while attempting to first read the data sector, a first jog value is generated in response to the gain control setting. The head is served over the data sector in response to the first jog value, and a second read of the data sector is performed.