US Patent No: 6,097,559

Number of patents in Portfolio can not be more than 2000

System and method for detecting head-to-disk contact in-situ a direct access storage device using a position error signal

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Abstract

An apparatus and method for detecting low flying read/write heads provides for the detection of contact between an air bearing slider/transducer assembly and a surface feature developed on a surface of a data storage disk. The apparatus includes a transducer disposed on an air bearing slider. An actuator is coupled to the slider/transducer assembly typically by employment of a head suspension assembly. The processor, in response to position error signals developed from servo information provided on the disk surface, moves the actuator and slider/transducer assembly to prescribed disk surface locations. The processor further processes non-repeatable position error signal values developed at a plurality of disk surface locations to detect an occurrence of contact between the slider/transducer assembly and a surface feature arising from the disk surface. Detecting the occurrence of a head-to-disk contact event generally involves acquiring position error signals from a first disk location and a second disk location using a particular transducer. The processor computes a power ratio value using a first power value and a second power value respectively derived from non-repeatable position error signals acquired from the first and second disk locations. The processor then compares the power ratio value with a power ratio threshold value, such that a power ratio value exceeding the power ratio threshold value indicates an occurrence of contact between the air bearing slider and a surface feature of the disk. The head-to-disk contact detection methodology of the present invention may be field upgradable in-situ a data storage system.

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First Claim

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Patent Owner(s)

Patent OwnerAddressTotal Patents
HGST NETHERLANDS B.V.AMSTERDAM, NL3016

International Classification(s)

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  • [Patents Count]

Inventor(s)

Inventor Name Address # of filed Patents Total Citations
Ottesen, Hal Hjalmar Rochester, MN 80 1718
Smith, Gordon James Rochester, MN 128 1443

Cited Art

Patent Info (Count) # Cites Year
 
KABUSHIKI KAISHA TOSHIBA (2)
5,831,781 Method and apparatus for detecting flying height variation of head in disk storage system 50 1996
6,014,282 Magnetic disk apparatus and method of detecting head fault 14 1997
 
SEAGATE TECHNOLOGY LLC (2)
5,901,001 Detection of asperities in recording surface of storage medium 25 1996
6,008,640 Detection and measurement of head disc interference using read back signal (without acoustic emission sensor or laser doppler vibrometer) 39 1997

Patent Citation Ranking

Forward Cites

Patent Info (Count) # Cites Year
 
SEAGATE TECHNOLOGY LLC (8)
6,822,814 Write head collision detection using MR read element in disc drives 3 2001
7,194,802 Tool for certifying a head-gimbal assembly 4 2002
7,430,083 Virtual head fly profile measurement 3 2003
7,391,586 Servowriter ramp detection 3 2006
7,690,100 Techniques for certifying a head-gimbal assembly 1 2007
7,952,829 Detecting contact between a slider and a data storage medium without a separate contact-detection voltage source 0 2008
7,804,661 Microactuator control that avoids thermal asperities on disk surfaces 0 2008
7,889,447 Readback signal-based head-disc contact detection using AM/FM demodulation 1 2009
 
WESTERN DIGITAL TECHNOLOGIES, INC. (8)
7,551,390 Disk drive to characterize misaligned servo wedges 2 2007
7,839,595 Feed forward compensation for fly height control in a disk drive 4 2008
7,630,162 Disk drive servoing off of first head while determining fly height for second head 7 2008
7,675,707 Disk drive employing repeatable disturbance compensation for fly height control 6 2008
8,320,069 Disk drive detecting positive correlation in fly height measurements 0 2010
8,059,357 Disk drive adjusting fly height when calibrating head/disk contact 2 2010
7,916,420 Disk drive employing comb filter for repeatable fly height compensation 3 2010
8,300,338 Disk drive correlating different fly height measurements to verify disk warpage 0 2010
 
MARVELL INTERNATIONAL LTD. (7)
7,199,961 Detecting fly height of a head over a storage medium 24 2003
7,136,250 Detecting fly height of a head over a storage medium 22 2005
7,359,139 Detecting fly height of a head over a storage medium 10 2007
7,518,820 Detecting fly height of a head over a storage medium 5 2008
7,986,487 Harmonic sensor 2 2009
8,154,820 Harmonic sensor 0 2011
8,422,160 Harmonic sensor 0 2012
 
HGST NETHERLANDS B.V. (4)
6,710,952 System and method for gracefully relinquishing a computer hard disk drive from imminent catastrophic failure 6 2000
6,587,301 System and method for calibrating and controlling the internal pressure of a hard disk drive 11 2000
6,680,806 System and method for gracefully relinquishing a computer hard disk drive from imminent catastrophic failure 13 2002
7,206,159 Method and apparatus for rejecting contact-induced disturbances 5 2005
 
HITACHI GLOBAL STORAGE TECHNOLOGIES NETHERLANDS B.V. (3)
6,522,495 System, method and program for determining the magnetic center shift within a disk drive system 5 1999
6,700,728 Method and disk drive for enhanced performance in the presence of stationary PES outliers 1 2001
6,985,317 Method and apparatus for testing the reliability of a disk drive 2 2002
 
WESTERN DIGITAL (FREMONT), LLC (3)
7,440,220 Method for defining a touch-down power for head having a flying height actuator 6 2007
7,436,620 Method for selecting an electrical power to be applied to a head-based flying height actuator 6 2007
7,583,466 Disk drive determining operating fly height by detecting head disk contact from disk rotation time 6 2007
 
EMC CORPORATION (2)
7,230,781 Information storage system, and a method of operating it 3 2003
7,567,398 Detection of fly height change in a disk drive 0 2007
 
MAXTOR CORPORATION (2)
6,721,121 In-situ determination of landing zone transition for improved disk drive reliability 7 2000
7,158,325 Disk drive head touchdown detection with improved discrimination 31 2004
 
AGENCY FOR SCIENCE, TECHNOLOGY AND RESEARCH (1)
6,888,694 Active control system and method for reducing disk fluttering induced track misregistrations 19 2002
 
KABUSHIKI KAISHA TOSHIBA (1)
7,599,141 Disk drive apparatus, electronic circuit for disk drive apparatus and powering method therefor 1 2007
 
TEXAS INSTRUMENTS INCORPORATED (1)
6,751,043 Digital servo control system for a hard disc drive using a voice coil motor in voltage mode 7 2001
 
TOSHIBA STORAGE DEVICE CORPORATION (1)
7,692,890 Flying height control method and circuit 1 2009