Western Digital Technologies, Inc.

Other

Phillip Scott Haralson

Galvin Chia

Naoto Ito

Joey Martin Poss

Pierre-Olivier Jubert

Dennis W Hogg

Huanxiang Ruan

Prakash Balasubramaniam

Farzad Novin

Bernhard E Knigge

Sukumar Rajauria

Memphis Zhihong Yin

Derrick E Burton

Kent Douglas Anderson

Steven R Vasquez

Poornima Nookala

Jimmy Zhang

Galvin T P Chia

Mark McDaniel

Navin E Prabhu

Clifford A Redden

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, wherein the selected head comprises a magnetic write element and a laser generating component; and one or more processing devices. The one or more processing devices are configured to measure a magnetic saturation responsiveness of the corresponding disk surface to heat-assisted write operations using a range of values of write laser current applied to the laser generating component. The one or more processing devices are further configured to calibrate a nominal write laser current of the selected head for the corresponding disk surface based on the measured magnetic saturation responsiveness of the corresponding disk surface.

Data storage device with laser write bias optimization using disk thermal-magnetic response mapping in heat-assisted magnetic recording

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 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 generate a determination of magnetic responsiveness to thermal energy of at least one position of the corresponding disk surface in response to an operation of the selected head. The one or more processing devices are further configured to determine and apply a pre-bias current to the thermally energizing component prior to a write operation, with the selected head proximate to the at least one position of the corresponding disk surface, wherein the pre-bias current is based on the determination of magnetic responsiveness to thermal energy of the at least one position of the corresponding disk surface.

Data storage device with laser pre-bias optimization using disk thermal-magnetic response mapping in heat-assisted magnetic recording

A data storage device is disclosed comprising a head actuated over an energy assisted magnetic media comprising a plurality of data tracks, wherein each data track comprises a plurality of data sectors. A write operation to a first data sector is executed by applying a first current to a write coil of the head while the head is over a second data sector preceding the first data sector, wherein the first current comprises a first amplitude. A second current is applied to the write coil while the head is over the first data sector, wherein the second current comprises a second amplitude lower than the first amplitude.

Data storage device pre-biasing write current for energy assisted magnetic recording

A data storage device is disclosed comprising a head actuated over a magnetic media. A write operation is executed to a first data sector by writing to at least part of a defective data sector preceding the first data sector in order to achieve a target fly height of the head prior to writing to the first data sector.

Data storage device writing to defective data sector for fly height control

A data storage device is disclosed comprising a first head actuated over a first disk surface, wherein the first head comprises a laser configured to heat the first disk surface while writing data to the first disk surface. A write power is applied to the laser and a first write operation is executed to write first data to the first disk surface during a first revolution of the first disk surface. A first transient decrease in an output power of the laser is detected during the first write operation, and when the first transient decrease in the output power of the laser is detected during the first write operation, a write-verify of the first data is executed during a second revolution of the first disk surface.

Data storage device modifying write operation when a laser mode hop is detected

An apparatus includes: a media; a heat assisted magnetic recording (HAMR) head over the media; and control circuitry, coupled to the HAMR head, the control circuitry being configured to: receive a write command to write the media; apply a dynamic flying height (DFH) control before asserting a write gate of the HAMR head; assert the write gate to the HAMR head; and enable a flying height compensation mechanism to maintain a constant value of a flying height of the HAMR head over the media during a next assertion of the write gate.

Electronic system with head management mechanism and method of operation thereof

A data storage device is disclosed comprising a first head actuated over a first disk surface, wherein the first head comprises a laser configured to heat the first disk surface while writing data to the first disk surface. A write power is applied to the laser when executing a first write operation, and the first write operation is paused when a transient increase in the output power of the laser is detected. In another embodiment, a write-verify of the written data is executed when a transient decrease in the output power of the laser is detected.

A data storage device is disclosed comprising a disk comprising a plurality of data sectors and a plurality of servo sectors, and a head actuated over the disk, wherein the head comprises a laser configured to heat the disk while writing data to the disk. When the head is over a first data sector not being written, a first prelase bias is applied to the laser, and when the head is over a servo sector, a second, lower prelase bias is applied to the laser. When the head is over a second data sector being written, a write bias higher than the first prelase bias is applied to the laser.

Data storage device boosting prelase bias while over data sector for heat assisted magnetic recording

A data storage device is disclosed comprising a head actuated over a disk, wherein the head comprises a laser configured to heat the disk while writing data to the disk. While writing data to the disk, an updated power setting for the laser is stored in a staging register, and during a non-write mode, the updated power setting is transferred from the staging register to an operating register in order to update an operating power for the laser.

Data storage device updating laser power during non-write mode for heat assisted magnetic recording

A data storage device is disclosed comprising a disk and a head actuated over the disk, wherein the head comprises a laser configured to heat the disk while writing data to the disk. The laser power is adjusted and a pattern is written to a target track at the adjusted laser power. The pattern is read from the target track to generate a read signal, and a quality metric is generated based on the read signal. The process is repeated at least once, and a write power for the laser is configured based on a slope of the quality metric.

Data storage device calibrating a laser power for heat assisted magnetic recording based on slope of quality metric

A data storage device is disclosed comprising a disk comprising a plurality of tracks and a head actuated over the disk, wherein the head comprises a read element radially offset from a write element. A first pattern is written to a single track, and the first pattern is read from the single track to generate a first read signal from which a first quality metric is generated. A second pattern is written to the single track, wherein the second pattern is different from the first pattern. The second pattern is read from the single track to generate a second read signal from which a second quality metric is generated. The radial offset of the read element and write element is measured based on the first and second quality metrics.

Data storage device measuring radial offset between read element and write element

A disk drive is disclosed comprising a head actuated over a disk, the head comprising a fly height actuator (FHA). A fly height of the head is measured, and a closed-loop fly height control signal is generated based on the measured fly height and a target fly height. The target fly height is adjusted based on a delta generated based on a change in an environmental condition, and an FHA control signal is applied to the FHA based on the closed-loop fly height control signal.

Disk drive adjusting closed-loop fly height target based on change in open-loop fly height control signal

A disk drive is disclosed comprising a plurality of disk surfaces, and a head actuated over each disk surface, where each head comprises a fly height actuator (FHA) operable to control a fly height of the head over the corresponding disk surface. A fly height is measured for each head to generate a plurality of fly height measurements. An average value is generated in response to the plurality of fly height measurements, and a first control value is generated for a first head based on the average value and the fly height measurement for the first head. The first FHA of the first head is controlled in response to the first control value.

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Huntington Beach, CA, United States of America

Phillip Scott Haralson