Method and disk drive for enhanced performance in the presence of stationary PES outliers

Number of patents in Portfolio can not be more than 2000

United States of America Patent

PATENT NO 6700728
APP PUB NO 20020191325A1
SERIAL NO

09873490

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ATTORNEY / AGENT: (SPONSORED)

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Abstract

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A method and apparatus are provided for enhanced performance in the presence of stationary position error signal (PES) outliers in a direct access storage device (DASD). A plurality of PES samples are obtained from a plurality of servo sectors around a track. Utilizing the PES samples, a normalized outlier value is computed for each of the plurality of servo sectors around the track. The computed normalized outlier values are sequentially stored and compared with a set threshold value. A stationary PES outlier is identified responsive to each stored outlier value being greater than the set threshold value. Each identified stationary PES outlier is utilized during predefined operations of the DASD. During a recalibration mode of the DASD, a different track for feedforward generation is selected to avoid an identified stationary PES outlier. When more than one stationary PES outlier is identified from the servo sectors around a track, then data from the track is reassigned to an alternate track and the flawed track is marked to avoid use for future data storage.

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Patent Owner(s)

Patent OwnerAddressTotal Patents
HITACHI GLOBAL STORAGE TECHNOLOGIES NETHERLANDS B.V.AMSTERDAM115

International Classification(s)

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Inventor(s)

Inventor Name Address # of filed Patents Total Citations
Ottesen, Hal Hjalmar Rochester, MN 80 2733
Smith, Gordon James Rochester, MN 127 2533

Cited Art Landscape

Patent Info (Count) # Cites Year
 
INTERNATIONAL BUSINESS MACHINES CORPORATION (1)
* 5241433 Disk drive servo control 33 1992
 
WESTERN DIGITAL TECHNOLOGIES, INC. (3)
* 6078445 Gain control for a dual burst, dual frequency PES servo pattern 22 1997
* 6097559 System and method for detecting head-to-disk contact in-situ a direct access storage device using a position error signal 66 1998
* 6226140 Shock detector in a disk drive servo control system 23 1998
 
SEAGATE TECHNOLOGY LLC (4)
* 5930068 Detecting servo defects in a disc drive 32 1996
* 6243224 Asynchronous digital demodulator and method for a null-type servo pattern 23 1999
* 6611397 Servo burst pattern defect detection 23 1999
* 6469849 Field ratioing demodulation circuit for a null-type servo pattern 18 2000
 
HITACHI GLOBAL STORAGE TECHNOLOGIES NETHERLANDS B.V. (1)
* 6219198 State estimator alteration for odd sample times in a disk drive servo control system 5 1998
 
RATEZE REMOTE MGMT. L.L.C. (2)
* 6545836 Servo control apparatus and method using absolute value input signals 29 1999
* 6594103 Read channel generating absolute value servo signal 34 1999
 
RESEARCH INVESTMENT NETWORK, INC. (1)
* 5510939 Disk drive with adaptive positioning 53 1992
* Cited By Examiner

Patent Citation Ranking

Forward Cite Landscape

Patent Info (Count) # Cites Year
 
Riospring, Inc. (1)
* 2006/0145,721 Testing printed circuit boards of disk drives and servo track writers 0 2004
 
HEADWAY TECHNOLOGIES, INC. (2)
* 2010/0238,588 FEED-FORWARD METHOD FOR REPEATABLE RUNOUT CANCELLATION 6 2009
7787210 Feed-forward method for repeatable runout cancellation 3 2009
* Cited By Examiner