An electronic device includes a sensing unit, a first control unit, and a second control unit. The sensing unit detects a parameter of the electronic device when the electronic device is tilted and sends a detection signal if the detected parameter exceeds the critical parameter. The first control unit and the second control unit receive the detection signal from the sensing unit. If the first control unit receives the detection signal before the second control unit, the first control unit controls the mechanical hard disk to power off and controls a magnetic head on the mechanical hard disk to reset from a working position to an original position. If the second control unit receives the detection signal before the first control unit, the second control unit controls the magnetic head on the mechanical hard disk to reset from the working position to the original position.

A modified hard disk drive (HDD) state is provided. The modified HDD state corresponds to a state wherein the heads of a hard disk drive assembly are parked as a baseline setting, but permitted to float over the platters for completing requests on a limited basis. This prioritizes HHD protection in certain contexts.

According to one embodiment, a magnetic disk device includes a disk, a first head, a second head, an actuator configured to position the first head and the second head over the disk, and a controller configured to control the actuator based on a first value having a first waveform suppressing a disturbance component, wherein the controller is configured to invert, in the first waveform, a polarity of a third waveform succeeding a first timing with respect to a polarity of a second waveform preceding the first timing in a case where the first head is changed to the second head at the first timing.

According to one embodiment, a magnetic disk device includes a base that includes a bottom wall and side walls standing along a circumference of the bottom wall, a housing that includes a cover facing the bottom wall and closing the base, an actuator assembly that is housed inside the housing and is rotatable around a rotation axis, a head movably supported by the actuator assembly, a control circuit board provided outside of the housing, a first sensor disposed on the control circuit board, and a second sensor disposed inside the housing.

According to one embodiment, a magnetic disk device includes an actuator assembly including an actuator block including a rotatable bearing unit, a plurality of heads movably supported by the actuator assembly, a first sensor provided to the actuator block, and a second sensor provided at a position different from the first sensor.

A data storage device is disclosed comprising a first disk comprising a first disk surface, a second disk comprising a second disk surface, an elevator actuator configured to actuate a head along an axial dimension relative to the first and second disks, a radial actuator configured to actuate the head radially over the first disk surface or the second disk surface, and a position sensor configured to generate a sinusoidal sensor signal representing a position of the head along the axial dimension. A crashstop_offset along the axial dimension is measured from a crashstop position of the elevator actuator to a zero crossing of the sinusoidal sensor signal.

According to one embodiment, a magnetic disk device includes a base that includes a bottom wall and side walls standing along a circumference of the bottom wall, a housing that includes a cover facing the bottom wall and closing the base, an actuator assembly that is housed inside the housing and is rotatable around a rotation axis, a head movably supported by the actuator assembly, a control circuit board provided outside of the housing, a first sensor disposed on the control circuit board, and a second sensor disposed inside the housing.

According to one embodiment, a magnetic disk device includes an actuator assembly including an actuator block including a rotatable bearing unit, a plurality of heads movably supported by the actuator assembly, a first sensor provided to the actuator block, and a second sensor provided at a position different from the first sensor.

According to one embodiment, a magnetic disk device includes a disk, a first head, a second head, an actuator configured to position the first head and the second head over the disk, and a controller configured to control the actuator based on a first value having a first waveform suppressing a disturbance component, wherein the controller is configured to invert, in the first waveform, a polarity of a third waveform succeeding a first timing with respect to a polarity of a second waveform preceding the first timing in a case where the first head is changed to the second head at the first timing.

According to one embodiment, a magnetic disk device includes a disk, a head, and a controller that estimates a first frequency component resulting from a disturbance in a first range of a frequency corresponding to the disturbance in a signal with the disturbance, estimates a second frequency component corresponding to a second frequency of a positive integral multiple of 2 or larger of a first frequency of the first frequency component in a second range different from the first range, and suppresses a first harmonic component corresponding to the positive integral multiple of the first frequency in a position error of a target position of the head on the disk.