International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Hitachi Global Storage Netherlands, B.v.

Peter Michael Baumgart

Andrew Ching Tam

Bernhard E Knigge

Thao Anh Nguyen

Wing P Leung

Michael Barenboim

Hong S Seing

Pieter J Kerstens

Peter P Chrusch

Benjamin Karni

Thomas R Albrecht

Chie Ching Poon

Gurinder P Singh

Benny Michael Harper

Karl Arthur Flechsig

Ullal Vasant Nayak

Anthony W Wu

Timothy C O'Sullivan

James Hammond Brannon

Hung V Nguyen

Huizong Lu

Michael F Lee

John Thomas Contreras

Bruce Alvin Gurney

Luiz M Franca-Neto

Virgil S Speriosu

Charles Mathew Mate

Michael G Lisanke

Dennis R Wilhoit

Ali Reza Taheri

Bernard Dieny

Lanphuong Thi Pena

Eric V Schnetzer

Iraj Kahkesh Pour

Maik Duwensee

Mathew Mate

Iraj Kakesh Pour

Son Van Nguyen

Erhard Theodor Schreck

Cherngye Hwang

Bruce Alexander Wilson

Steven W Meeks

Kurt A Rubin

Christopher S Gudeman

Tim Minvielle

Timothy Carl Strand

Thomas A Gregory

Gary Allan Herbst

Robert Nolan Payne

Andrei Khurshudov

Robert E Eaton

Jia-Yang Juang

Run-Han Wang

Douglas J Krajnovich

Russell Dean Moates

Gerard H Vurens

Fior D Sargent

Jorge Rubio

Martin Yu-Wen Chen

Pieter J M Kerstens

Richard Kroeker

Sujit Kirpekar

Charles Raymond Davis

Benjamin Kami

Ulla Vasant Nayak

Michael Luis Ramirez

Malk Duwensee

Doug John Krajnovich

Peter B Chrusch

Jean-Pierre Nozieres

Real time monitoring inconsistent operations in a hard disk drive, wherein the hard disk drive comprises a magnetic disk, a controller and a channel clock. A timing signal from the channel clock is measured in real time in the controller. Time intervals between sector identifier marks of the magnetic disk are detected using the timing signal from the channel clock during reading and writing operations of the hard disk drive in the controller. An inconsistency in the drive operations is detected in the controller based on changes in the time intervals between the sector identifier marks is detected during operation of the hard disk drive. The detection of the inconsistency in the drive operations is responded to.

Real time monitoring inconsistent operations in a hard disk drive

A system according to one embodiment includes a thin film stack having a magnetic transducer and a contact pad; and a heater in the thin film stack for inducing thermal protrusion of a media-facing side of the thin film stack, wherein the thin film stack is characterized by the contact pad protruding farther than the magnetic transducer upon the thin film stack being heated by the heater. A method for calibrating a protrusion of a magnetic head includes increasing a thermal protrusion of a magnetic head to induce head-medium contact; determining that the head has contacted the medium, wherein a portion of the head that contacts the medium is a contact pad or overcoat of the contact pad; determining parameters for inducing a desired amount of protrusion based in part on the determination that the head has contacted the medium; and storing the parameters.

System for controlling contact location during TFC touchdown and methods thereof

A hard disk drive (HDD) including a first resistive temperature detector (RTD) configured to detect a temperature generated by proximity of a slider and a media. The first RTD is proximate an air bearing surface (ABS) of the slider. The HDD also includes a second RTD configured to detect at least one temperature correlated to a fly-height of the slider. The second RTD is not required to be proximate the ABS of the slider. HDD also includes a read/write integrated circuit (IC) configured to determine the fly-height of the slider based on detection of temperatures by the first RTD and the second RTD.

Fly-height management in a hard disk drive (HDD)

A method of swaging a head gimbal assembly (HGA) to an actuator arm comprises positioning a tubular element on the HGA adjacent a hole in the actuator arm; restraining the subassembly; providing a rod formed from a shape memory alloy (SMA), the SMA having a martensitic phase at a low temperature and an austenitic phase above a phase transition temperature that is higher than the low temperature, the rod having an initial diameter that is smaller than diameters of the tubular element and the hole; extending the rod through the tubular element and hole; heating the rod above the phase transition temperature such that the rod expands to a second diameter that is greater than the initial diameter to plastically deform the HGA and swage together the HGA and actuator arm to form an assembly; cooling the rod and removing the rod from the assembly such that the rod returns to the initial diameter.

Method for joining components with shape memory alloys

Magnetic disk drive systems and associated methods are described for verifying a spacing between read/write heads on a slider and a magnetic recording disk during end-user operation. An operating power applied to heating elements in the slider controls the spacing due to thermal protrusion. While in end-user operation, the operating power is temporarily increased to a test power to decrease the spacing. The test power is then evaluated to determine if contact between the read/write heads and the magnetic recording disk is detected. If contact is not detected, then the spacing due to the operating power is determined to be adequate. If contact is detected, then the operating power is recalibrated.

Head spacing verification in magnetic disk drive systems during end-user operation

In a method of actively controlling slider fly height, a modulated radio frequency (RF) carrier signal is received from a slider. The modulated RF carrier signal comprises an amplitude modulated component which is modulated onto the modulated RF carrier signal by vibration of the slider. The amplitude associated with the amplitude modulated component is measured. Thermal fly height control (TFC) voltage generation is controlled by feeding back on the amplitude. A TFC voltage to apply to the slider is generated such that a selected amplitude of the amplitude modulated component is achieved and maintained. The selected amplitude is associated with a particular preselected fly height of the slider above a surface of a disk. The TFC voltage is provided to the slider.

Active fly height control using radio frequency feedback

In a method of pre-contact detection and active damping of air bearing vibrations in a hard disk drive, a slider is isolated from ground. The slider is then capacitively coupled with a hard disk of the hard disk drive via a thermal fly-height control (TFC) heating element. An alternating current (AC) signal is applied to the slider via the TFC heating element to control the amplitude of the slider.

Method and system for pre-contact detection and active damping of air bearing vibrations in a hard disk drive

A method according to one embodiment comprises detecting a change in a rotational velocity of a magnetic disk or a spindle coupled to the magnetic disk, the change being caused by head-disk contact. A method for detecting head-disk contact according to another embodiment comprises measuring a rotational velocity of a magnetic disk or a spindle coupled to the magnetic disk; detecting a change in the rotational velocity, the change being caused by head-disk contact; and correlating the change in rotational velocity with the head-disk contact.

Method and system for detecting a change in a rotational velocity of a magnetic disk or a spindle coupled to the magnetic disk

In method of feedback control for active damping of slider air bearing vibrations in a hard disk drive slider, a slider is isolated from ground. A velocity signal is acquired from the slider. The velocity signal is filtered to acquire a vibration signal. The vibration signal is adjusted in amplitude to achieve an amplitude adjusted vibration signal. The amplitude adjusted vibration signal is applied to the slider to actively dampen vibrations in the slider.

Method of feedback control for active damping of slider air bearing vibrations in a hard disk drive slider

A method and system for determining contact potential voltages between a slider body and a hard disk of a hard disk drive. In embodiments of the present invention, at least one continuous negative direct current (DC) voltage is applied between a slider body and a hard disk of a hard disk drive. Then, at least one continuous positive direct current (DC) voltage is applied between the slider body and the hard disk. A contact potential voltage between the slider body and the hard disk is then determined in response to the applying of the direct current voltages.

Method and system for determining contact potential in a hard disk drive

A method and system for measuring slider body clearance in a hard disk drive using positive and negative electrical pulses. In one embodiment, at least one positive direct current (DC) pulse is applied between a slider body and a hard disk of the hard disk drive. Furthermore, at least one negative direct current (DC) pulse is applied between the slider body and the hard disk. A contact potential voltage between said slider body and said hard disk is then determined in response to applying the at least one positive direct current (DC) pulse and the at least one negative direct current (DC) pulse.

Measurement of slider body clearance in a magnetic disk drive using positive and negative electrical pulses

A method for simultaneously measuring contact potential and slider body clearance in a hard disk drive. In embodiments of the present invention, a plurality of direct current (DC) pulses are applied between a slider body and a hard disk of a magnetic disk drive. The contact potential voltage between the slider body and the hard disk is determined in response to applying the plurality of direct current (DC) pulses. The voltage of the plurality of direct current (DC) pulses is increased until a contact between the slider body and the hard disk is detected.

Simultaneous measurement of contact potential and slider body clearance in a magnetic disk drive

A method and system for determining localized contact potential voltages and localized clearance data between a slider body and a hard disk of a hard disk drive. In embodiments of the present invention, a plurality of direct current (DC) pulses are applied between said slider body and a discreet location of the hard disk. In embodiments of the present invention, the discreet location of the hard disk comprises a portion of a data track of the hard disk. In embodiments of the present invention, a variation in the clearance of the slider body is determined when a given voltage is applied. Furthermore, a first set of DC pulses has a positive/negative bias while a second set of DC pulses has a negative/positive bias. The voltage of the sets of DC pulses is increased until a contact between the slider body and the hard disk is detected.

Disk drive with localized clearance and contact potential measurement capability

In a method of feedback control for active damping of slider air bearing vibrations in a hard disk drive slider, a slider is isolated from ground. A slider velocity signal is filtered to acquire a vibration signal. The vibration signal is adjusted in amplitude to achieve an amplitude adjusted vibration signal. The amplitude adjusted vibration signal is applied to the slider to actively dampen air bearing vibrations in the slider.

An electrical potential difference between a slider body and a hard disk of a hard disk drive is eliminated based on the flying-height spacing of the slider body between the slider body and the hard disk. A predetermined bias voltage is applied between the slider body and the hard disk that includes a DC component and an AC component and that is based on the detected flying-height spacing of the slider body. The flying-height spacing can be detected based a minimum slider-to-disk clearance change from a design flying height of the slider at a frequency of the AC component as the DC component of the predetermined bias voltage is varied. Alternatively, the flying-height spacing can be detected based on a minimum electrodynamic response of the slider to a first harmonic of the AC frequency of the AC component as the DC component is varied.

Method for actively controlling electric potential at the head/disk interface of a magnetic recording disk drive

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San Jose, CA, United States of America

Peter Michael Baumgart