Seagate Technology Incorporated

Burroughs, Inc.

Western Digital Technologies, Inc.

Other

Exabyte Corporation

Irwin Magnetic Systems, Inc.

Housan Dakroub

Edward Charles Gage

Tim Rausch

Alvin E Cox

Kaizhong Gao

Steven S Eckerd

Alfredo Gay Sam

Song Sheng Xue

Todd Michael Lammers

Jason Charles Jury

Hieu Van Nguyen

Jon David Trantham

Bruce Douglas Buch

Shaoping Li

James Gary Wessel

Mark R Ayres

Insik Jin

Sining Mao

Jan-Ulrich Thiele

Dadi Setiadi

James Dillon Kiely

John West Dykes

Barmeshwar Vikramaditya

Dennis W Hogg

Raul Horacio Andruet

Stefan Andrei Ionescu

Jeffrey A Heydt

Mukund Channagiri Rao

Thomas Lee Schick

Ghassan M Abdelnour

Michael L Bolt

Marlin K Klumpp

Christine Green

Jeffrey Howard Lake

Mike Montemorra

Mallika Roy

Charles Paul Henry

Richard A Farkas

David J Concannon

William Bruce Fitzpatrick

Jin Insik

The implementations disclosed herein provide for a storage device including a preamplifier that dynamically adjusts at least one of a rise time and fall time of an analog write current pulse based on a length of a corresponding write transition and/or characteristics of a media location where the write transition is to be recorded.

Preamplifier for adjustable write current

A transducer is configured to interact with a magnetic storage medium, a first channel comprises a first sensor and first circuitry configured to adjust a plurality of first channel parameters, and a second channel comprises a second sensor and second circuitry configured to adjust a plurality of second channel parameters. The first and second channel parameters are independently adjustable by the first and second circuitry, respectively. A detector is coupled to the first and second channels, and configured to detect a head-medium interface event.

Clearance sensor and circuitry using adjustable channel parameters

A circuit may be configured to reduce the power consumption and extend the life of a near field transducer of a heat-assisted magnetic recording (HAMR) device by pulsing a laser. The current that drives the laser may be of a frequency and magnitude so as to approximate the value of a continuous current in a continuous, non-pulsed laser. A system on chip (SOC), which may include a HAMR channel, can generate a laser data signal that may be synchronous with, and offset from, a write signal by a certain period of time, and may calculate certain parameters such as peak current and pulse width that may be applied to the signals in a preamp. The preamp signals can be used to program data to a disc medium.

HAMR channel to preamp interface

Polarity transitions of a write signal applied to a write coil correspond to first bit boundaries written to a magnetic recording media. A heat signal is applied to heat the magnetic recording media via a heat source while bits are being written. The heat signal includes negative pulses that de-energize the heat source during cooling periods corresponding to the writing of the first bit boundaries. The negative pulses are offset from the polarity transitions by a predetermined time.

Cooling periods used during the writing of bit boundaries to a magnetic recording media

Controlling a laser diode involves activating a first current source in preparation for writing to a magnetic recording medium. The first current source applies a threshold current to a laser diode that brings the laser diode close to an operating point. Responsive to a write signal, a second current source is activated that applies a write current to the laser diode. A combination of the write current and the threshold current fully energizes the laser diode and is less than a target recording current. Coincident with the activation of the second current source, a photodiode is activated that is optically coupled to the laser diode. The activated photodiode causes a feedback current to be applied to the laser diode.

Magnetic recording laser diode control

An apparatus includes a write element configured to apply a magnetic field to write data on a portion of a heat-assisted magnetic recording media in response to an energizing current. An energy source is configured to heat the portion of the media being magnetized by the write element. A preheat energizing current is applied to the write element during an interval before writing the data to the portion of the media. The preheat energizing current does not cause data to be written to the media and brings at least one of the write element and driver circuitry into thermal equilibrium prior to writing the data on the portion.

Heat assisted magnetic recording device with pre-heated write element

A first parameter associated with a writer preamp is defined. A write current of the writer preamp is adjusted in accordance with the first parameter so that an asymmetric signal is applied at a write head. The asymmetric signal results in symmetric writing of bits to a medium.

Adjusting a preamp write current to apply an asymmetric signal at a write head

A disk drive is disclosed. The disk drive comprises a disk, a head configured to write data to and read data from the disk, and an actuator configured to position the head relative to the disk. The disk drive also comprises a die including internal circuitry electrically coupled to the head and a bypass trace electrically coupled to the actuator, wherein the internal circuitry comprises one or more preamplifiers and the bypass trace is electrically isolated from the internal circuitry.

Actuator trace through a die

Data storage systems are provided. Data storage systems illustratively include a recording head having a writing element and a bit patterned medium having a plurality of media dots. In some embodiments, the plurality of media dots pass the recording head at a media dot frequency. In some embodiments, the writing element writes data to the bit patterned media at a writing frequency that is less than the media dot frequency.

BPM recording with more than one dot per bit

A disk drive comprising a head actuated over a disk, and a touchdown sensor for generating a sensor signal. The sensor signal is filtered using at least three bandpass filters to generate at least three filtered signals. The fly height of the head is decreased until one of the filtered signals indicates the head has contacted the disk.

Finding touchdown frequency for a head in a disk drive

The disclosure is related to detecting a fault condition of a transducer for reading and writing data to a data storage medium. The fault condition can be detected based on a potential difference between a reference voltage and a common mode of the transducer.

Monitoring transducer potential to detect an operating condition

A system includes a magnetic device for writing to and reading from a magnetic medium and a sensor disposed adjacent to the magnetic device and proximate to the magnetic medium. The sensor generates signals related to thermal variations in the sensor caused by changes in a distance between the magnetic device and the magnetic medium.

Magnetic recording device including a thermal proximity sensor

A readback system includes a magnetic sensor that receives a sensor current. The magnetic sensor senses magnetic bits at a bit frequency and generates a sensor output. The readback system includes a channel circuit that modulates the sensor current at a modulation frequency higher than the bit frequency. The channel circuit samples the sensor output and combines multiple samples of the sensor output per magnetic bit into a combined sample output.

Readback system providing a combined sample output including multiple samples per bit

Method and apparatus for characterizing the flight characteristics of a read/write head. A disc is accelerated to a selected rotational velocity sufficient to aerodynamically support the head. The head is positioned over a portion of the disc non-accessible to customer data and a magnetoresistive element of the read/write is biased using a suitable voltage or current. A media noise landing signature obtained as the element transduces white noise from the surface identifies the head as a low-flying head.

Media noise low-fly height test for a disc drive

Growing community of inventors

Dearborn Heights, MI, United States of America

Housan Dakroub