Western Digital Technologies, Inc.

Shravankumar Girish Bhat

Gary Allan Herbst

Hideaki Ito

Shrey Khanna

Christopher David Wiederholt

Yuanyuan Zhao

Kun Zhang

Yongzhi Liu

Various illustrative aspects are directed to a data storage device, comprising one or more disks; an actuator mechanism configured to position heads proximate to a recording medium of the disks; a spindle motor configured for rotating the one or more disks; and one or more processing devices comprising a servo control processor. The servo control processor is configured to receive a spindle speed error signal indicative of an error in a rotational speed of the spindle motor. The servo control processor is further configured to output an initial frequency offset signal, wherein the initial frequency offset signal is proportional to the spindle speed error signal.

Data storage device with servo control processor with initial fast lock of disk lock clock

Example systems, data storage devices, and methods to provide data protection during concurrent operations for multiple actuator data storage devices are described. The data storage device includes a plurality of actuators configured to actuate a plurality of heads over different subsets of a plurality of disk surfaces. Responsive to receiving a write command for one of the actuators, the coupling state with at least one other of the actuators is determined and execution of write commands is inhibited if the coupling state indicates a possible coupling event. The inhibit of the write commands in the presence of coupling events may prevent off-track writes and protect data.

Data protection during concurrent operations for multiple actuator data storage devices

A data storage device is disclosed comprising a first plurality of heads actuated over a first subset of disk surfaces by a first servo control loop comprising a first coarse actuator and a first fine actuator, and a second plurality of heads actuated over a second subset of the disk surfaces by a second servo control loop comprising a second coarse actuator and a second fine actuator. A plurality of access commands are received, wherein each access command is associated with one of the heads. While executing a first access command using the first servo control loop, a disturbance is ramped while injecting the disturbance into the second servo control loop, and the second fine actuator is calibrated based on the disturbance.

Data storage device calibrating fine actuator by ramping disturbance to attenuate servo transient

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Broomfield, CO, United States of America

Shravankumar Girish Bhat