Hitachi Global Storage Technologies Netherlands B.v.

Western Digital Technologies, Inc.

Other

Hgst Netherlands, B.v.

Wd Media, LLC

Hitachi Global Storage Netherlands, B.v.

Bernhard E Knigge

Peter Michael Baumgart

John Thomas Contreras

Luiz M Franca-Neto

Joey Martin Poss

Charles Mathew Mate

Thomas R Albrecht

Noureddine Kermiche

Zvonimir Z Bandic

Jian J Xu

Robert Nolan Payne

Robert E Eaton

James P R McFadyen

Ronald Chang

Erhard Theodor Schreck

Bruce Alexander Wilson

Donald Ray Gillis

Kurt A Rubin

Bruno Jean Marchon

Oscar Jaime Ruiz

Petrus Antonius Van Der Heijden

Qinghua Zeng

Gary Allan Herbst

Gurinder P Singh

Jia-Yang Juang

Mathew Mate

Maik Duwensee

Martin Yu-Wen Chen

Toshiki Hirano

Michael L Mallary

Stefan Maat

Mike Suk

Qing Dai

Norbert A Feliss

Bernd Lamberts

Remmelt Pit

Elizabeth Ann Dobisz

Michael Anthony Moser

Derrick E Burton

Andreas Moser

Dennis W Hogg

Ullal Vasant Nayak

Phillip Scott Haralson

Walton Fong

Stanley H Shepherd

Naoto Ito

Jih-Ping Peng

Gabriel Zeltzer

Kazuhiro Saito

Lisha Wang

Mousumi Mani Biswas

Steven Nowlen Guilliams

Puneet Bhargava

Sujit Kirpekar

Karthik Venkatesh

Abhishek Srivastava

Charles Raymond Davis

Richard Kroeker

Zhen Ye

Mousumi M Biswas

Malk Duwensee

A data storage device comprises a first resistive temperature detector (RTD) and a second RTD coupled to a first voltage source. A tuning bridge coupled between the first and second RTDs and a second voltage source reduces offset between a first bias voltage across the first RTD and a second bias voltage across the second RTD. A low noise amplifier (LNA) receives the first and second bias voltages as a differential bias voltage. A modulator coupled between the first and second RTDs and the LNA modulates the differential bias voltage.

Differential sense of embedded contact sensor (ECS) and near-field temperature sensor (NTS) utilizing chopping amplifier

Various illustrative aspects are directed to a data storage device, comprising one or more disks; an actuator mechanism configured to position one or more heads proximate to a corresponding disk surface of the one or more disks; and one or more processing devices. The one or more processing devices are configured to receive signals indicative of conditions of a write operation by the selected head. The one or more processing devices are further configured to determine, based on the signals, a verification status indicating whether the write operation was successful. The one or more processing devices are further configured to output the verification status within a selected time limit.

Data storage device with write protection and guaranteed rapid write verification in energy-assisted recording (EAR)

Various illustrative aspects are directed to a data storage device comprising a disk, a read/write head configured to read data from and write data to the disk, a laser diode (LD) coupled to a nearfield transducer configured to heat an area of the disk near the read/write head, a first resistive temperature detector (RTD), a second RTD, and one or more processing devices configured to: apply a laser bias to the LD during a write operation; obtain a plurality of differential signal measurements, based at least in part on a plurality of measurements from each of the first and second RTDs; and adjust the laser bias applied to the LD, based at least in part on comparing the plurality of differential signal measurements to a target value for the differential signal.

Laser mode hop compensation using multi-sector feedback in heat assisted magnetic recording

A data storage device comprises a disk and a head having a read and write elements. A read heater is powered based on a dual heater ratio (DHR) to thermally adjust a spacing of the read element from a disk surface, and a write heater is powered based on the DHR to thermally adjust a spacing of the write element from the disk surface. A read spacing slope profile is determined comprising read touchdowns (TDs) over a range of DHRs, and a write spacing slope profile is determined comprising write TDs over the range of DHRs. An operating DHR of the head is set to be where the read spacing slope profile intersects the write spacing slope profile.

Pole tip recession compensation by dual heater ratio optimization in a hard disk drive

Various illustrative aspects are directed to a data storage device, comprising one or more disks; an actuator mechanism configured to position a selected head among one or more heads proximate to a corresponding disk surface among the one or more disks; and one or more processing devices. The one or more processing devices are configured to generate a map of laser mode hop effects across the corresponding disk surface, for the selected head. The one or more processing devices are further configured to apply a laser mode hop mitigation in operating the selected head, based on the map of laser mode hop effects.

Data storage device with mapping and mitigation of laser mode hop effects in heat-assisted magnetic recording (HAMR)

Various illustrative aspects are directed to a data storage device comprising a slider with a resistive temperature detector (RTD) having a first resistance electrically connected to a first amplifier and a plurality of controlled current sources and switches, and one or more processing devices configured to: control the switches to generate an alternating-bias signal having a first clock frequency for biasing the first resistance, modulate an input signal of the first amplifier using the first clock frequency to generate a modulated signal, demodulate an amplified modulated signal at an output of a second amplifier using the first clock frequency to generate a resistance detection signal, the second amplifier coupled to the first amplifier, and process the resistance detection signal to determine the first resistance and/or a change in value of the first resistance.

Alternating-bias signal resistance detection for resistive temperature detectors in disk drives

Methods are provided for utilizing machine learning operations configured for use in processing missing pieces of visual data in image data to predict potential location of defects and/or damage in storage device disks. These predictions can allow for a sufficient ability to categorize disks during storage device quality inspections. This can allow for quality inspections to conclude before all areas of the disk surface are scanned. Because less surface area of the disks within the storage device require scanning, the time required for quality inspection scanning prior to deployment can be greatly reduced. Additionally, the partial scans occurring prior to deployment may be supplemented or updated after deployment through the performance of a dense scan. These secondary scans can be configured to scan all previously unscanned areas during storage device downtimes or in response to an environmental trigger such that the storage device will not exhibit any loss in performance.

Machine learning supplemented storage device inspections

Various illustrative aspects are directed to a data storage device comprising a slider with a resistive temperature detector with a first resistance, a resistance detection circuit electrically coupled to the first resistance and comprising a low and high frequency path corresponding to a DC and AC mode, respectively, and one or more processing devices configured to: bias the first resistance with a voltage bias, where the first resistance is coupled to a first and second amplifier, control a pulse generator to add a bias pulse on the HF path to generate a HF resistance detection signal, where the second amplifier is biased using the voltage bias and the bias pulse, control a clock to chop a LF signal at the first amplifier on the LF path, demodulate the chopped LF signal to generate a LF resistance detection signal, and concurrently process the HF and LF resistance detection signals.

Continuous dual path resistance detection for resistive temperature detectors in disk drives

Various illustrative aspects are directed to a data storage device comprising a disk; a read/write head having read and write portions configured to read data from and write data to the disk; read and write heaters configured to thermally adjust read and write spacings of the read and write portions from the disk surface; and a controller configured to control power applied to the read and write heaters based on a dual heater power ratio (DHR) of the respective power applied to each heater. The DHR is set based on a point during touchdown at which a reader shield and a writer shield have maximum contact with the surface of the disk (DHRmax).

Adaptive dual heater mode for hard disk drive

A data storage device is disclosed comprising a head actuated over a disk, wherein the head comprises a fly height actuator (FHA). A FHA control signal is applied to the FHA, wherein the FHA control signal comprises a DC component and an AC component. A fly height metric is measured representing a fly height of the head over the disk for different levels of the DC component. A modulation amplitude of the fly height metric is detected, and a minimum in the modulation amplitude of the fly height metric is detected.

Data storage device detecting minimum stable fly height of a head over a disk

Lubricants having perfluoropolyether side chains which have a high thermal stability and high shear modulus.

Lubricants with high thermal stability for heat-assisted magnetic recording

A novel lubricant comprising a fluorinated graphene nanoribbon for a magnetic recording media structure is disclosed. The magnetic recording media structure includes a substrate, a magnetic recording layer for recording information disposed over the substrate, a protective overcoat layer for protecting the magnetic recording layer disposed over the magnetic recording layer, and a lubricant layer disposed over the protective overcoat layer and comprising a fluorinated graphene nanoribbon.

Lubricants comprising fluorinated graphene nanoribbons for magnetic recording media structure

A disk drive is disclosed comprising a disk, and a slider comprising a head, where the head comprises a write component electrically insulated from the slider. A bias voltage is applied to the write component, and a current flowing between the write component and the disk is measured, wherein the current is indicative of a fly height of the head.

Disk drive measuring fly height by applying a bias voltage to an electrically insulated write component of a head

A data storage device is disclosed comprising a disk, a head comprising a touchdown sensor, and a fly height actuator (FHA) configured to actuate the head vertically over the disk based on an FHA setting. The data storage device is configured into a read mode, and while in the read mode, the FHA setting is adjusted until the head contacts the disk and a touchdown read mode resistance of the touchdown sensor is measured. The data storage device is configured into a write mode and the FHA setting is adjusted so the head is not contacting the disk. While in the write mode, a non-touchdown write mode resistance of the touchdown sensor is measured, and a write touchdown FHA setting that will cause the head to contact the disk while in the write mode is estimated based on the touchdown read mode resistance and the non-touchdown write mode resistance.

Data storage device calibrating fly height actuator based on read mode touchdown resistance of touchdown sensor

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San Jose, CA, United States of America

Bernhard E Knigge