Jie Zhen Yu

US Patent:

6636377, Oct 21, 2003

Filed:

Jun 30, 2000

Appl. No.:

09/608573

Inventors:

Jie Yu - Irvine CA
David B. Joan - Trabuco Canyon CA

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B 5596

US Classification:

360 7807, 360 7808, 360 7806, 360 7809

Abstract:

A method of tuning a servo control system in a disk drive that implements seeks using a the feed-forward command effort signal u and a PES reference signal r that were designed to be compatible with one another on the basis of a modeled frequency response G (z) that is different from an actual frequency response G(z). The steps includes scaling the feed-forward command effort signal u to substantially achieve a zero velocity condition at an end of the seek; scaling the feed-forward command effort signal u to substantially achieve an on-target condition at the end of the seek; and modifying the PES reference signal r such that it substantially varies in unison with the indicated PES signal y during the seek.

US Patent:

6987639, Jan 17, 2006

Filed:

Sep 30, 2003

Appl. No.:

10/676578

Inventors:

Jie Yu - Irvine CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B 5/55

US Classification:

360 7804, 360 7809, 710 39, 711112, 711167

Abstract:

A disk drive is disclosed comprising a disk, a head, and a voice coil motor (VCM) for actuating the head over the disk. The disk drive executes a rotational position optimization (RPO) algorithm to select a next command to execute relative to an estimated seek time computed for each command in a command queue. A motor capability of the VCM is estimated and used to modify the estimated seek time for each command in the command queue to thereby optimize the RPO algorithm.

US Patent:

7050254, May 23, 2006

Filed:

Feb 11, 2005

Appl. No.:

11/056201

Inventors:

Jie Yu - Irvine CA, US
Hasnorhafiza Husni - Selangor, MY
Jian Chen - Irvine CA, US
Hong Wan Tham - Selangor, MY

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B 5/02

US Classification:

360 55

Abstract:

Disclosed is a disk drive that provides for internal disk drive temperature estimation. The disk drive includes an actuator, a head attached to the actuator, a disk to store data, a preamplifier connected to the head to amplify read and write signals, and a processor for controlling operations in the disk drive including moving the actuator such that the head is moved to read data from and write data to the disk. The processor under the control of a program is further utilized to calculate a junction temperature (J) based on a breakthrough voltage of the preamplifier, apply a filter to the calculated Jto compensate for temperature noise, and to estimate an internal disk drive temperature based upon the filtered J.

US Patent:

7054098, May 30, 2006

Filed:

Jun 1, 2004

Appl. No.:

10/860339

Inventors:

Jie Yu - Irvine CA, US
David D. Nguyen - Fountain Valley CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B 5/596

US Classification:

360 7806, 360 7804

Abstract:

A disk drive is disclosed comprising a disk, an actuator arm, a head connected to a distal end of the actuator arm, and a voice coil motor (VCM) for rotating the actuator arm about a pivot to actuate the head over the disk, wherein the VCM rotates the actuator arm into a latched positioned when the disk drive is idle. Disk drive control circuitry unlatches the actuator arm by applying a driving current to the VCM according to an open-loop current profile. The open-loop current profile comprises an acceleration pulse having an acceleration magnitude and an acceleration interval, and a deceleration pulse having a deceleration magnitude and a deceleration interval. The deceleration magnitude is substantially smaller than the acceleration magnitude, and the deceleration interval is substantially longer than the acceleration interval, to thereby attenuate acoustic noise when unlatching the actuator arm.

US Patent:

7061714, Jun 13, 2006

Filed:

Dec 19, 2003

Appl. No.:

10/741785

Inventors:

Jie Yu - Irvine CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B 5/596

US Classification:

360 7807, 360 7808, 711111, 318560, 318632

Abstract:

A disk drive is disclosed comprising a disk, a head, and a voice coil motor (VCM) for actuating the head over the disk. The disk drive executes a rotational position optimization (RPO) algorithm to select a next command to execute relative to an estimated seek time computed for each command in a command queue. A seek time parameter is estimated and a seek time delta computed in response to the estimated seek time parameter. The seek time delta is added to a nominal estimated seek time to generate a modified estimated seek time for each command in the command queue, thereby optimizing the RPO algorithm.

US Patent:

7388728, Jun 17, 2008

Filed:

Sep 22, 2006

Appl. No.:

11/525411

Inventors:

Teddy T. C. Chen - Huntington Beach CA, US
Jinsheng Bill Jang - Irvine CA, US
Jie Yu - Irvine CA, US
Masao Miyamura - Diamond Bar CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B 5/596

US Classification:

360 7708

Abstract:

A perpendicular media recording (PMR) servo track writer (STW) system and method for writing servo sectors onto a disk is disclosed. The servo writer includes a head positioner to position a head of a head disk assembly (HDA) relative to a disk, wherein the head writes servo sectors onto the disk with a perpendicular flux. The servo writer includes a controller to control the head positioner such that the head writes servo sectors onto the disk from one of an inner diameter (ID) or an outer diameter (OD) of the disk to a middle diameter (MD) of the disk, respectively, followed by writing servo sectors between the other of the OD or the ID of the disk to the MD of the disk, respectively.

US Patent:

7466509, Dec 16, 2008

Filed:

Sep 22, 2006

Appl. No.:

11/525406

Inventors:

Teddy T. C. Chen - Huntington Beach CA, US
Jinsheng Bill Jang - Irvine CA, US
Jie Yu - Irvine CA, US
Jonathan V Nguyen - Laguna Niguel CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B 21/02

US Classification:

360 75

Abstract:

A disk drive operable with first and second servo patterns in a perpendicular media recording (PMR) environment is disclosed. The disk drive comprises a head operable with a perpendicular flux, a disk, and a servo controller. The disk includes a plurality of tracks, wherein each track has a plurality of servo sectors utilized in seek operations. The servo sectors of the disk include a first servo pattern between one of an inner diameter (ID) or an outer diameter (OD) of the disk and a middle diameter (MD) of the disk, respectively, and a second servo pattern between the other of the OD or the ID of the disk and the MD of the disk, respectively. The servo controller operates in a first mode when seeking within one of the first or second servo patterns and a second mode when seeking between the first servo pattern and the second servo pattern.

US Patent:

7518819, Apr 14, 2009

Filed:

Aug 31, 2007

Appl. No.:

11/849029

Inventors:

Jie Yu - Irvine CA, US
Guoxiao Guo - Foothill Ranch CA, US
Jack M. Chue - Los Altos CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B 21/02
G11B 27/36

US Classification:

360 75, 360 31, 360 7708, 360 7814

Abstract:

A disk drive is disclosed comprising a disk having a plurality of tracks, wherein each track comprises a plurality of data sectors and a plurality of servo sectors. The disk drive further comprises a head actuated over the disk, the head comprising a read element radially offset from a write element by a reader/writer offset. In order to rewrite a marginal servo sector detected in a target track, control circuitry within the disk drive relocates user data recorded in a first data sector of a near adjacent track to a staging memory. Servo data is written over the first data sector, and the read element is used to read the servo data written over the first data sector to actuate the head to rewrite the marginal servo sector of the target track. The user data stored in the staging memory is then rewritten to the first data sector.