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 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.

A disc drive includes a data storage surface having a system data zone and a user data zone, and a head that communicates with the data storage surface. The disc drive also includes a control circuit communicatively coupled to the head. The control circuit is configured to, during power up initialization of the disc drive, apply a fly height control value to direct the head to fly at a first target fly height for reading system data from the system data zone. The first target fly height is substantially higher than a second target fly height for reading user data from the user data zone. The control circuit determines whether an actual fly height of the head is substantially equal to the first target fly height. The control circuit performs fly height correction when the actual fly height is not substantially equal to the first target fly height.

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 magnetic disk including at least one servo zone that includes a first data storage track with a first servo pattern having a first frequency and a second data storage track with a second servo pattern having a second frequency, wherein the first data storage track is located closer to an outer diameter of the magnetic disk than the first data storage track and the first frequency is greater than the second frequency; a magnetic head that faces the magnetic disk; and a zone servo switching unit that switches a servo pattern frequency employed to position the magnetic head in a radial direction based on a radial position of the magnetic head.

A data storage device has a closed loop extended park mode during spin down operation. A data storage device comprises a spindle motor configured to rotate one or more disks, and one or more processing devices. The one or more processing devices are configured to determine a value of current that is discharged from the spindle motor over time during a spin down of the spindle motor, and control a braking duty cycle for braking the spindle motor during the spin down such that the value of current discharged from the spindle motor over time does not exceed a selected current limit.

A data storage device is disclosed comprising a voice coil motor (VCM) and a secondary actuator configured to actuate a head over a disk. A position error signal (PES) is generated based on servo data recorded on the disk, and a first control signal is generated based on the PES. The PES is adjusted based on the first control signal to generate a first adjusted PES, and a second control signal is generated based on the first adjusted PES. A secondary actuator control signal is generated based on the first control signal and the second control signal, wherein the secondary actuator control signal is applied to the secondary actuator. The first adjusted PES is adjusted based on the second control signal to generate a second adjusted PES, and a VCM control signal is generated based on the second adjusted PES, wherein the VCM control signal is applied to the VCM.

A magnetic disk device includes a magnetic disk, a magnetic head, a voice coil motor which drives movement of the magnetic head relative to the magnetic disk, a drive circuit which drives the voice coil motor, a memory in which a seek time for a seek operation is stored in association with a seek distance of the magnetic head, and a controller. The controller changes the seek time stored in the memory in association with the seek distance based on a temperature and a power supply voltage of the drive circuit.

A microactuator for a dual stage actuated suspension for a hard disk drive is constructed as a longitudinal stack of piezoelectric (PZT) elements acting in the d33 mode, expanding or contracting longitudinally when an electric field is applied across them in the longitudinal direction. The microactuator has interlaced electrode fingers that separate and define the individual PZT elements, and apply the electric field. A stiff constraint layer having a high Young's modulus is affixed to the microactuator on the side opposite the suspension to which the microactuator is bonded. The constraint layer may be a layer of substantially inactive PZT material that is formed integrally with the PZT elements but without electrodes in the inactive PZT layer. The presence of the stiff constraint layer increases the effective stroke length of the microactuator.

Embodiments of disk drive head suspensions are described that include a spring metal layer. The spring metal layer includes a base region, support arms extending from the base region, and a slider mounting region. The slider mounting region includes a proximal portion, a distal portion, and a pair of motor openings. The motor openings are configured to receive motors such that the longitudinal axes of the motors are non-parallel with the longitudinal axis of the slider mounting region. The suspensions include traces that include a base portion on the base region of the spring metal layer, a spring metal-unsupported portion extending from the base region to the slider mounting region, and a slider mounting portion extending from the spring metal-unsupported portion onto the slider mounting region. And, the suspensions include an insulating layer between portions of the spring metal layer and the conductor layer.