Western Digital Technologies, Inc.

Western Digital (fremont), Inc.

Eric J Champion

Kroum Stanimirov Stoev

Christopher B Wolf

Gerardo Bertero

Michael Alex

Matthew R Gibbons

Adam F Torabi

Shaoping Li

Michael L Mallary

Qunwen Leng

James N Malina

Francis H Liu

Ge Yi

William C Cain

Davide Guarisco

A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of tracks, each track comprising a plurality of data sectors. A circular buffer is defined comprising a plurality of the tracks. During a garbage collection operation, write data is read from previously written valid data sectors corresponding to a tail of the circular buffer and stored in a non-volatile cache. During a flush operation, the write data is flushed from the non-volatile cache to the disk.

Disk drive using non-volatile cache when garbage collecting log structured writes

A method and system provide a magnetic transducer including a first shield, a plurality of read sensors, and a second shield. The read sensors are between the first shield and the second shield. The read sensors have a plurality of widths in a track width direction and are separated by at least one distance in a down track direction. The down track direction is perpendicular to the track width direction.

Multiple sensor array usable in two-dimensional magnetic recording

A perpendicular magnetic recording (PMR) disk used in energy assisted magnetic recording drives is described. The PMR disk includes a substrate, a magnetic recording layer disposed above the substrate, an exchange coupling layer disposed above the magnetic recording layer, and a capping layer disposed above the exchange coupling layer. The capping layer has a Curie temperature greater than the Curie temperature of the magnetic recording layer.

Energy assisted magnetic recording medium capable of suppressing high DC readback noise

A disk drive is disclosed comprising a head actuated over a disk, wherein the head comprises a laser operable to heat the disk while writing data to the disk. An initial laser power of the laser is configured. After a time interval, an operating laser power of the laser is measured, and when the operating laser power falls below the initial laser power, a control signal applied to the laser is first adjusted until the operating laser power substantially matches the initial laser power. After first adjusting the control signal applied to the laser, a quality metric representing a recording quality of the head is measured, and when the quality metric indicates a poor recording quality, the control signal applied to the laser is second adjusted so that the operating laser power exceeds the initial laser power.

Disk drive calibrating laser power and write current for heat assisted magnetic recording

A disk drive is disclosed comprising a head actuated over a disk, wherein the head comprises a write element, a read element, and a laser operable to heat the disk while writing data to the disk. The disk is magnetized by writing a first test pattern to the disk using the write element and a first power applied to the laser. The magnetization of the first test pattern is destabilized by heating the disk using a second power applied to the laser, wherein the second power is less than the first power. After destabilizing the magnetization of the first test pattern, the first test pattern is read with the read element to generate a read signal, and the read signal is evaluated to detect a defect on the disk.

Disk drive destabilizing magnetization of test pattern using head laser to enhance defect detection

Embodiments described herein include systems and methods for correcting for errors caused by disturbances to disk drives, such as disturbances due to shocks or vibrations incident on the drive. For example, systems and methods described herein advantageously correct for corruption to current data as well as previously written. Data may be rewritten in the current track that was being written to when the disturbance occurred, and may also be rewritten to one or more nearby previously written tracks, such as one or more adjacent tracks. According to some aspects, the direction of head deviation is used to select the appropriate corrective action.

Directional write retry for shingled disk drive application

A near field transducer (NFT) for use in an energy assisted magnetic recording (EAMR) head and configured to direct energy to a recording media is disclosed. The NFT comprises a disk section; and a pin section extending towards an air bearing surface (ABS) from the disk section. The pin section has a proximal end adjoining the disk section and a distal end opposite to the proximal end and facing the ABS, wherein the distal end of the pin section has a non-rectangular cross section in a plane parallel to the ABS and the proximal end of the pin section has a rectangular cross section in the plane parallel to the ABS.

Recording head with near field transducer having non-rectangular pin cross section

A method and system for providing an EAMR transducer is described. The EAMR transducer has an ABS and is coupled with a laser. The EAMR transducer includes a write pole, coil(s), and an energy delivery device. The write pole magnetically writes to the media. The coil(s) energize the write pole. The energy delivery device is optically coupled with the laser and includes a top distal from the ABS, a bottom proximate to the ABS, a first side, and a second side opposite to the first side. The first side has a first apex angle from a normal to the ABS and is reflective. The second side has a second apex angle from the normal and is reflective. The first and second apex angles are each at least three and not more than twenty-five degrees. The first and second sides converge such that the top is wider than the bottom.

Energy-assisted magnetic recording head having waveguide capable of providing small beam spots

A method and system for writing data to a media utilizing an energy assisted magnetic recording (EAMR) head are described. The EAMR head includes at least one laser and at least one EAMR transducer. The laser(s) provide energy. The EAMR transducer(s) are coupled with the laser. The EAMR transducer(s) are configured to direct the energy to spot(s) on the media and to write a plurality of tracks of data in a block. The method and system include writing a track of the plurality of tracks on the media within the spot(s) using the EAMR transducer and stepping a track pitch along a particular radial direction on the media. The method and system also include repeating the writing and stepping steps until the plurality of tracks for the block is written.

Method and system for performing EAMR recording at high density using a large thermal spot size

A near field transducer (NFT) for use in an energy assisted magnetic recording (EAMR) head and configured to direct energy to a recording media is disclosed. The NFT comprises a disk section; and a pin section extending towards an air bearing surface (ABS) from the disk section. The pin section has a proximal end adjoining the disk section and a distal end opposite to the proximal end and facing the ABS, wherein at least the distal end of the pin section has a non- rectangular cross section in a plane parallel to the ABS.

Trailing edge optimized near field transducer having non-rectangular pin cross section

An energy assisted magnetic recording (EAMR) head for writing to a recording media is disclosed. The EAMR head includes a write pole for providing a magnetic field for writing to the recording media; and a near field transducer disposed adjacent to the write pole and comprising a disk section and a pin section extending towards an air bearing surface (ABS) from the disk section. At least a portion of the pin section is electrically isolated from the write pole by an insulator material.

Trailing edge optimized near field transducer

A discrete track perpendicular magnetic recording (PMR) disk and a method of fabricating the disk are described. The PMR disk may include a heat sink layer disposed above a substrate, intermediate layers disposed above the heat sink layer, and a magnetic recording layer disposed above the intermediate layers. The magnetic recording layer may have raised and recessed areas, where a heat conductive material may be disposed within one or more of the recessed areas.

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San Jose, CA, United States of America

Eric J Champion