JP2007250170A - 磁気抵抗信号振幅によって磁気記録ディスクドライブ内のヘッド・ディスク間接触を決定するシステムおよび方法 - Google Patents

磁気抵抗信号振幅によって磁気記録ディスクドライブ内のヘッド・ディスク間接触を決定するシステムおよび方法 Download PDF

Info

Publication number
JP2007250170A
JP2007250170A JP2007063507A JP2007063507A JP2007250170A JP 2007250170 A JP2007250170 A JP 2007250170A JP 2007063507 A JP2007063507 A JP 2007063507A JP 2007063507 A JP2007063507 A JP 2007063507A JP 2007250170 A JP2007250170 A JP 2007250170A
Authority
JP
Japan
Prior art keywords
disk
head
hdc
slider
actuator
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2007063507A
Other languages
English (en)
Japanese (ja)
Other versions
JP2007250170A5 (enExample
Inventor
Yong Shen
ヨン・シェン
Jing Zhang
ジグ・チャン
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
HGST Netherlands BV
HGST Inc
Original Assignee
Hitachi Global Storage Technologies Netherlands BV
Hitachi Global Storage Technologies Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Global Storage Technologies Netherlands BV, Hitachi Global Storage Technologies Inc filed Critical Hitachi Global Storage Technologies Netherlands BV
Publication of JP2007250170A publication Critical patent/JP2007250170A/ja
Publication of JP2007250170A5 publication Critical patent/JP2007250170A5/ja
Pending legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
    • G11B5/58—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B5/60—Fluid-dynamic spacing of heads from record-carriers
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/33—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only
    • G11B5/39—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects
    • G11B5/3903—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects using magnetic thin film layers or their effects, the films being part of integrated structures
    • G11B5/3906—Details related to the use of magnetic thin film layers or to their effects
    • G11B5/3945—Heads comprising more than one sensitive element
    • G11B5/3948—Heads comprising more than one sensitive element the sensitive elements being active read-out elements
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
    • G11B5/58—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B5/60—Fluid-dynamic spacing of heads from record-carriers
    • G11B5/6005—Specially adapted for spacing from a rotating disc using a fluid cushion
    • G11B5/6011—Control of flying height
    • G11B5/6029—Measurement using values derived from the data signal read from the disk

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Recording Or Reproducing By Magnetic Means (AREA)
JP2007063507A 2006-03-14 2007-03-13 磁気抵抗信号振幅によって磁気記録ディスクドライブ内のヘッド・ディスク間接触を決定するシステムおよび方法 Pending JP2007250170A (ja)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US11/376,660 US7292401B2 (en) 2006-03-14 2006-03-14 System and method for determining head-disk contact in a magnetic recording disk drive by magnetoresistive signal amplitude

Publications (2)

Publication Number Publication Date
JP2007250170A true JP2007250170A (ja) 2007-09-27
JP2007250170A5 JP2007250170A5 (enExample) 2010-03-25

Family

ID=38517519

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2007063507A Pending JP2007250170A (ja) 2006-03-14 2007-03-13 磁気抵抗信号振幅によって磁気記録ディスクドライブ内のヘッド・ディスク間接触を決定するシステムおよび方法

Country Status (3)

Country Link
US (1) US7292401B2 (enExample)
JP (1) JP2007250170A (enExample)
CN (1) CN101038769A (enExample)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011065719A (ja) * 2009-09-17 2011-03-31 Hitachi Global Storage Technologies Netherlands Bv ヘッドスライダ及び磁気ディスク装置
JP2011210358A (ja) * 2010-03-26 2011-10-20 Samsung Electronics Co Ltd データ保存装置におけるヘッドとメディア間のタッチダウン及び接触の検出方法及びその装置並びにこれを適用したディスクドライブ及び記録媒体
JP2021101400A (ja) * 2019-12-24 2021-07-08 株式会社東芝 磁気ディスク装置
US11887634B2 (en) 2022-03-24 2024-01-30 Kabushiki Kaisha Toshiba Magnetic disk device and control method of magnetic disk device

Families Citing this family (38)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4255869B2 (ja) * 2004-03-24 2009-04-15 ヒタチグローバルストレージテクノロジーズネザーランドビーブイ 磁気ディスク装置およびそれに用いる磁気ヘッドスライダ
JP2007066460A (ja) * 2005-09-01 2007-03-15 Hitachi Global Storage Technologies Netherlands Bv 磁気ヘッド評価装置及びそれを用いた磁気ディスク装置の製造方法
US7558015B2 (en) * 2006-03-29 2009-07-07 Maxtor Corporation Actuation efficiency based contact detection
US7423830B2 (en) * 2006-04-10 2008-09-09 Iomega Corporation Detecting head/disk contact in a disk drive using a calibration parameter
JP2007293948A (ja) * 2006-04-21 2007-11-08 Fujitsu Ltd 情報記録再生装置、ヘッド浮上量制御方法、ヘッド浮上制御回路
US7508616B2 (en) * 2006-05-18 2009-03-24 Seagate Technology Llc Regulating data writes responsive to head fly height
US20070291401A1 (en) * 2006-05-19 2007-12-20 Maxtor Corporation Contact detection using calibrated seeks
JP2008047241A (ja) * 2006-08-18 2008-02-28 Tdk Corp 浮上量測定方法及び浮上量の調整が可能な磁気ディスク装置
US20080055772A1 (en) * 2006-09-01 2008-03-06 Mcmillan Chris Method and apparatus for predicting contact of a read-write head in a hard disk drive
US20080088962A1 (en) * 2006-10-17 2008-04-17 Samsung Electronics Co., Ltd. Detection of HDI in disk drives using read back signal
US20080291564A1 (en) * 2007-05-25 2008-11-27 Samsung Electronics Co., Ltd. Detecting head-disk contact during off-track operations
JP2008293625A (ja) * 2007-05-28 2008-12-04 Hitachi Global Storage Technologies Netherlands Bv ヘッドとディスクとの間のクリアランスを制御する制御値を決定する装置、その方法及び磁気ディスク・ドライブ装置
JP2009032325A (ja) * 2007-07-26 2009-02-12 Fujitsu Ltd 記憶装置、制御方法及び制御ユニット
US7583466B2 (en) * 2007-11-15 2009-09-01 Western Digital (Fremont), Llc Disk drive determining operating fly height by detecting head disk contact from disk rotation time
US7724461B1 (en) * 2007-12-21 2010-05-25 Western Digital Technologies, Inc. Determining head non-linearity in a disk drive
US7933085B2 (en) * 2008-03-31 2011-04-26 Hitachi Global Storage Technologies Netherlands, B.V. Head spacing verification in magnetic disk drive systems during end-user operation
US7920346B2 (en) * 2008-05-21 2011-04-05 Sae Magnetics (H.K.) Ltd. Method for testing performance of a magnetic head slider
US7965459B2 (en) * 2008-12-18 2011-06-21 Seagate Technology Llc Wavelets-based detection of proximity between a sensor and an object
US20100157765A1 (en) * 2008-12-19 2010-06-24 Seagate Technology Llc Collection of readback signal modulation data
US7719786B1 (en) * 2008-12-23 2010-05-18 Hitachi Global Storage Technologies Netherlands B.V. Active fly height control using radio frequency feedback
US7830634B2 (en) * 2008-12-23 2010-11-09 Hitachi Global Storage Technologies Netherlands, B.V. Head-disk contact detection and work function difference determination
US7889447B2 (en) * 2009-01-14 2011-02-15 Seagate Technology Llc Readback signal-based head-disc contact detection using AM/FM demodulation
US8665546B1 (en) 2010-01-07 2014-03-04 Western Digital Technologies, Inc. Adaptive threshold for detecting touchdown or contamination
KR20110108180A (ko) * 2010-03-26 2011-10-05 삼성전자주식회사 헤드의 터치-다운 검출 방법 및 이를 이용한 헤드 부상 높이 조정 방법 및 디스크 드라이브
US8730611B2 (en) 2011-02-28 2014-05-20 Seagate Technology Llc Contact detection
CN102280112B (zh) * 2011-04-13 2013-12-18 华中科技大学 一种用于硬盘驱动器的热飞高控制滑块
US9053740B1 (en) 2011-05-04 2015-06-09 Western Digital Technologies, Inc. Disk drive determining touchdown threshold
US8643981B2 (en) * 2011-12-28 2014-02-04 HGST Netherlands B. V. Magnetic domain control for an embedded contact sensor for a magnetic recording head
US8611036B2 (en) * 2012-05-06 2013-12-17 HGST Netherlands B.V. Disk drive with head thermal fly-height actuator and controller for compensation of write head expansion
US8797671B2 (en) 2012-05-17 2014-08-05 HGST Netherlands B.V. Excitation of airbearing oscillation with tar nearfield device for touchdown detection
US8582231B1 (en) 2012-06-06 2013-11-12 Western Digital Technologies, Inc. Disk drive determining head touchdown threshold based on curve fitting prediction error
US20140063644A1 (en) * 2012-08-29 2014-03-06 Seagate Technology Llc Magnetic Element with Multiple Selective Transducing Elements
US8891193B1 (en) 2013-05-09 2014-11-18 Western Digital Technologies, Inc. Disk drive calibrating threshold and gain of touchdown sensor
US9384774B1 (en) 2015-03-23 2016-07-05 Western Digital Technologies, Inc. Data storage device calibrating a laser power for heat assisted magnetic recording based on slope of quality metric
US9373346B1 (en) 2015-06-27 2016-06-21 International Business Machines Corporation Adjustable spacing formatter head
US11315592B1 (en) 2021-02-10 2022-04-26 Seagate Technology Llc Adjusting HGA z-height via HSA elevator using head/actuator feedback
US11875830B2 (en) 2021-02-10 2024-01-16 Seagate Technology Llc Adjusting HGA z-height via HSA elevator using head/actuator feedback
US11900965B2 (en) 2022-02-14 2024-02-13 Seagate Technology Llc Z-height control for disc drive using servo wedge timing

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0944979A (ja) * 1995-07-31 1997-02-14 Toshiba Corp ディスク記録再生装置及びディスク記録再生装置に適用するヘッド衝突検出装置
JPH10188248A (ja) * 1996-09-19 1998-07-21 Hitachi Ltd サーボ信号処理回路及びそれを用いた磁気ディスク装置

Family Cites Families (48)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5021906A (en) 1989-10-31 1991-06-04 International Business Machines Corporation Programmable air bearing slider including magnetic read/write element
US5130866A (en) 1990-07-17 1992-07-14 International Business Machines Corporation Method and circuitry for in-situ measurement of transducer/recording medium clearance and transducer magnetic instability
JP2884774B2 (ja) 1990-12-01 1999-04-19 株式会社日立製作所 情報記憶装置及びその製法
US5455730A (en) 1993-02-18 1995-10-03 International Business Machines Corporation Contact magnetic recording disk file with a magnetoresistive read sensor
US6088176A (en) * 1993-04-30 2000-07-11 International Business Machines Corporation Method and apparatus for separating magnetic and thermal components from an MR read signal
US5777815A (en) * 1996-06-13 1998-07-07 International Business Machines Corporation Disk drive with shock detection based on thermoresistive signal from magnetoresistive head
US5909330A (en) 1996-12-12 1999-06-01 Maxtor Corporation Method and apparatus for detecting head flying height in a disk drive
US5991113A (en) 1997-04-07 1999-11-23 Seagate Technology, Inc. Slider with temperature responsive transducer positioning
US6735027B2 (en) 1998-06-02 2004-05-11 Texas Instruments Incorporated Head fly height by using the applied peak area ratio to determine signal PW50
US6275345B1 (en) 1998-12-02 2001-08-14 International Business Machines Corporation System and method for estimating a frequency of slider airbearing resonance
US6570730B1 (en) * 1999-06-09 2003-05-27 Seagate Technology, Llc. Shear-based transducer for HDD read/write element height control
US6344949B1 (en) 1999-07-13 2002-02-05 International Business Machines Corporation Flying height adjustment for air bearing sliders
US6452735B1 (en) * 1999-07-19 2002-09-17 Maxtor Corporation Disk drive that monitors the flying height of a dual element transducer using a thermally induced signal during write operations
US6417981B1 (en) * 1999-09-23 2002-07-09 International Business Machines Corporation System and method for measuring absolute transducer-medium clearance using a thermal response of an MR transducer
US6501606B2 (en) * 1999-12-02 2002-12-31 Seagate Technology Llc Fly height control for a read/write head over patterned media
JP3647708B2 (ja) 2000-02-09 2005-05-18 ヒタチグローバルストレージテクノロジーズネザーランドビーブイ 磁気ヘッド浮上量異常検出方法、データ書込方法およびハード・ディスク・ドライブ装置
US6600622B1 (en) * 2000-02-11 2003-07-29 Hitachi Global Storage Technologies Netherlands B.V. System and method for detecting displacement of disk drive heads on micro actuators due to contact with disks
US6407874B1 (en) 2000-03-30 2002-06-18 International Business Machines Corporation Method and apparatus for detection slider airbearing resonance using SAT P-list data
US6479988B2 (en) * 2000-06-06 2002-11-12 Tdk Corporation Method and apparatus for testing thin-film magnetic head
US6611399B1 (en) 2000-12-07 2003-08-26 Seagate Technology Llc Micro-actuated micro-suspension(MAMS) slider for both fly height and tracking position
US6717776B2 (en) 2001-01-19 2004-04-06 Seagate Technology Llc Adjustable fly height control using an adjustable head actuator assembly
US6785079B2 (en) 2001-03-16 2004-08-31 Hitachi Global Storage Technologies Netherlands B.V. Method and apparatus for estimating the flyheight of an airbearing slider in a storage device
US6775103B2 (en) 2001-04-02 2004-08-10 Hitachi Global Storage Technologies Netherlands B.V. Slider head having thermally controlled distal end and assembly with a rotating disc
US6865040B2 (en) 2001-05-22 2005-03-08 Seagate Technology, Llc Method and system for measuring fly height
US6801376B2 (en) * 2001-06-21 2004-10-05 Hitachi Global Storage Technologies Netherlands B.V. Method and apparatus for evaluating a head-disk interface condition for disk drives
US6898034B2 (en) 2001-10-10 2005-05-24 Seagate Technology Llc Fly height measurement for a disc drive
US6765745B2 (en) 2001-12-28 2004-07-20 Hitachi Global Storage Technologies Netherlands, B.V. Method and apparatus for in situ detection of high-flying sliders over customer data
US7486457B2 (en) * 2002-02-15 2009-02-03 Hitachi Global Storage Technologies Netherlands B.V. Method and apparatus for predicting write failure resulting from flying height modulation
KR100468766B1 (ko) 2002-09-19 2005-01-29 삼성전자주식회사 헤드와 디스크간의 플라잉 높이를 제어하기 위한 방법 및그 제어장치
JP3626954B2 (ja) 2003-03-12 2005-03-09 Ｔｄｋ株式会社 薄膜磁気ヘッドの製造方法、薄膜磁気ヘッド、ヘッドジンバルアセンブリ及びハードディスク装置
JP2004335069A (ja) 2003-04-14 2004-11-25 Tdk Corp 薄膜磁気ヘッド、ヘッドジンバルアセンブリ、及び、ハードディスク装置
US6940691B2 (en) 2003-04-30 2005-09-06 Hitachi Global Storage Technologies Netherlands B.V. Electrically resistive heating device for data storage systems
US7133254B2 (en) 2003-05-30 2006-11-07 Hitachi Global Storage Technologies Netherlands B.V. Magnetic recording head with heating device
US7038875B2 (en) 2003-07-31 2006-05-02 Seagate Technology Llc Dynamic measurement of head media spacing modulation
JP4072469B2 (ja) 2003-08-01 2008-04-09 株式会社日立グローバルストレージテクノロジーズ 磁気ヘッドスライダおよび磁気ディスク装置
JP4223897B2 (ja) 2003-08-28 2009-02-12 ヒタチグローバルストレージテクノロジーズネザーランドビーブイ サーマルプロトリューション量を浮上量管理に用いる機能を持つ磁気ディスク装置、その機能を有す検査装置。
US6947246B2 (en) 2003-08-29 2005-09-20 Hitachi Global Storage Technologies Netherlands, B.V. Large protrusion recording head for controlled magnetic spacing recording/reading
US7016131B2 (en) 2003-08-29 2006-03-21 Agency For Science, Technology And Research Method and implementation of in-situ absolute head medium spacing measurement
US7054084B2 (en) 2003-08-29 2006-05-30 Hitachi Global Storage Technologies Netherlands B.V. Method, apparatus and program storage device for sensing increased resistance changes in an MR element to detect MR sensor events
US6972919B2 (en) 2003-09-05 2005-12-06 Hitachi Global Storage Technologies Netherlands, B.V. Increasing head-disk interface reliability using controlled heating
US6975472B2 (en) 2003-09-12 2005-12-13 Seagate Technology Llc Head with heating element and control regime therefor
US20050094303A1 (en) 2003-11-04 2005-05-05 Tom Chan Flying height monitor with servo AGC voltage for write operation in a hard disk drive
JP4131950B2 (ja) 2003-11-04 2008-08-13 ヒタチグローバルストレージテクノロジーズネザーランドビーブイ 回転円板形記憶装置
US8531796B2 (en) * 2004-01-09 2013-09-10 International Business Machines Corporation Fly height extraction system
US7119979B2 (en) * 2004-06-30 2006-10-10 Hitachi Global Storage Technologies Netherlands B.V. Measurement of slider clearance by inducing collision of the slider with disk surface
JP2006252593A (ja) * 2005-03-08 2006-09-21 Hitachi Global Storage Technologies Netherlands Bv 磁気ディスク装置、制御方法及び製造方法
US7215495B1 (en) * 2005-12-27 2007-05-08 Hitachi Global Storage Technologies Netherlands B.V. System and method for determining head-disk contact in a magnetic recording disk drive
US7180692B1 (en) * 2005-12-27 2007-02-20 Hitachi Global Storage Technologies Netherlands B.V. System and method for calibrating and controlling a fly-height actuator in a magnetic recording disk drive

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0944979A (ja) * 1995-07-31 1997-02-14 Toshiba Corp ディスク記録再生装置及びディスク記録再生装置に適用するヘッド衝突検出装置
JPH10188248A (ja) * 1996-09-19 1998-07-21 Hitachi Ltd サーボ信号処理回路及びそれを用いた磁気ディスク装置

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011065719A (ja) * 2009-09-17 2011-03-31 Hitachi Global Storage Technologies Netherlands Bv ヘッドスライダ及び磁気ディスク装置
JP2011210358A (ja) * 2010-03-26 2011-10-20 Samsung Electronics Co Ltd データ保存装置におけるヘッドとメディア間のタッチダウン及び接触の検出方法及びその装置並びにこれを適用したディスクドライブ及び記録媒体
JP2021101400A (ja) * 2019-12-24 2021-07-08 株式会社東芝 磁気ディスク装置
JP7293105B2 (ja) 2019-12-24 2023-06-19 株式会社東芝 磁気ディスク装置
US11887634B2 (en) 2022-03-24 2024-01-30 Kabushiki Kaisha Toshiba Magnetic disk device and control method of magnetic disk device

Also Published As

Publication number Publication date
US20070217051A1 (en) 2007-09-20
US7292401B2 (en) 2007-11-06
CN101038769A (zh) 2007-09-19

Similar Documents

Publication Publication Date Title
US7292401B2 (en) System and method for determining head-disk contact in a magnetic recording disk drive by magnetoresistive signal amplitude
US7215495B1 (en) System and method for determining head-disk contact in a magnetic recording disk drive
US7180692B1 (en) System and method for calibrating and controlling a fly-height actuator in a magnetic recording disk drive
CN1074565C (zh) 带有基于磁致电阻磁头的热阻信号的冲击检测的磁盘驱动器
US8711508B2 (en) Contact detection between a disk and magnetic head
US7423830B2 (en) Detecting head/disk contact in a disk drive using a calibration parameter
JP3723651B2 (ja) 磁気抵抗ヘッドの熱応答を復元するための方法および装置
US8416521B2 (en) Magnetic recording and reproduction device and flying height control method
US20090002870A1 (en) Flying height measurement and control with user data signal
US6611397B1 (en) Servo burst pattern defect detection
US10395678B1 (en) Method and system for determining slider-disk contact in a magnetic recording disk drive with dual fly-height actuators
US7489466B2 (en) Enabling intermittent contact recording on-demand
US7656600B2 (en) Monitoring transducer potential to detect an operating condition
US20130335852A1 (en) In-Situ Contact Potential Measurement in Hard-Disk Drives
US9595280B2 (en) Hard disk drive head-disk interface dithering
US20030184899A1 (en) Low flying head detection using readback signal amplitude modulation
US8804275B1 (en) System and method for determining head-disk contact in a magnetic recording disk drive having a fly-height actuator
US6611389B1 (en) Method of determining the variation of the clearance between a magnetic transducer and a recording media during track seeking
US20140240871A1 (en) Interface voltage control operating point determination in a hard disk drive
US7933085B2 (en) Head spacing verification in magnetic disk drive systems during end-user operation
JP2005507538A (ja) 低振幅スキップ書込み検出器
US20030030934A1 (en) In-situ detection of transducer magnetic instability in a disc drive
US7224548B1 (en) Determining contact write current in disk drive using position error signal variance
US20080291564A1 (en) Detecting head-disk contact during off-track operations
US6483657B1 (en) Head flight characterization using thermal asperity detection

Legal Events

Date Code Title Description
A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20100208

A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20100208

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20110520

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20110607

A02 Decision of refusal

Free format text: JAPANESE INTERMEDIATE CODE: A02

Effective date: 20111101