Western Digital Technologies, Inc.

Hongchao Tim Zhao

Jiangang Liang

Soo-Choon Kang

Guoxiao Guo

Siri S Weerasooriya

Don Brunnett

Duc H Banh

Kazuhiro Saito

Yilin Cai

David Scott C Amiss

Jianfeng Xu

A data storage device is disclosed comprising a head actuated over a disk, wherein the head comprises a spin torque oscillator (STO). A first bias signal is applied to the STO during a first interval preceding a write operation to write data to the disk, wherein the first bias signal causes the STO to protrude toward the disk. After the first interval, a second bias signal is applied to the STO during a second interval spanning at least part of the write operation, wherein an amplitude of the first bias signal is in the range of 1.1 to 1.5 times an amplitude of the second bias signal.

Data storage device pre-biasing a spin torque oscillator prior to a write operation

A method is disclosed for selecting a global digital-to-analog setting for a plurality of heads in a disk drive, the disk drive comprising a plurality of disk surfaces and a plurality of respective heads. The method comprises: adjusting a first digital-to-analog setting for a first head to generate a first signal, adjusting a second digital-to-analog setting for a second head to generate a second signal, selecting a first scalar setting for scaling the first signal, selecting a second scalar setting for scaling the second signal, and selecting the global digital-to-analog setting in response to the adjusted first digital-to-analog setting, the adjusted second digital-to-analog setting, the first scalar setting, and the second scalar setting.

Disk drive selecting a global digital-to-analog setting for a plurality of heads

A disk drive is disclosed comprising a head actuated over a disk, and a fly height actuator operable to control a fly height of the head over the disk. A periodic control signal is applied to the fly height actuator, a frequency response of a touchdown metric at a frequency of the periodic control signal is measured, and a touchdown event is detected in response to the frequency response of the touchdown metric.

Disk drive detecting touchdown event by evaluating frequency response of a touchdown metric

A disk drive is disclosed comprising a disk, a head for writing data to the disk, and control circuitry coupled to the head. The control circuitry is operable to determine a first set of fly height values and determine a threshold based on the first set of fly height values. The control circuitry determines a second set of fly height values, adjusts the threshold based on the second set of fly height values, and detects a head characteristic based on the adjusted threshold. The head characteristic is detected by detecting a head touchdown event and/or detecting contamination related to the head based on the adjusted threshold.

Adaptive threshold for detecting touchdown or contamination

A disk drive to reduce head instability during disk drive manufacturing is disclosed. The disk drive comprises: a disk; a dynamic flying height (DFH) read/write head; a flying height actuator to control the spacing between the DFH read/write head and the disk; and a controller. The controller controls operations in the disk drive including applying a sloped increasing power between a first voltage and a second voltage to move the DFH read/write head towards the disk.

Disk drive to reduce head instability

A method is disclosed for selecting a dynamic fly height (DFH) control setting for a head in a disk drive, the disk drive comprising a plurality of disk surfaces and plurality of respective heads. The method comprises servoing a first head over a first disk surface in response to servo data recorded on the first disk surface, adjusting a DFH control setting for a second head, and while servoing the first head over the first disk surface, detecting whether the second head has contacted a second disk surface.

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San Jose, CA, United States of America

Hongchao Tim Zhao