Various illustrative aspects are directed to a data storage device comprising: a voice coil motor (VCM) and one or more processing devices, configured to actuate the VCM, switch on measuring a back electromotive force (BEMF) from the VCM for intervals of an initial BEMF measurement that are free of spikes in the initial BEMF measurement, and process a measured BEMF signal from the intervals of the initial BEMF measurement that are free of spikes in a change of current term of the initial BEMF measurement.

Various illustrative aspects are directed to a data storage device comprising: a voice coil motor (VCM) and one or more processing devices, configured to actuate the VCM, switch on measuring a back electromotive force (BEMF) from the VCM for intervals of an initial BEMF measurement that are free of spikes in the initial BEMF measurement, and process a measured BEMF signal from the intervals of the initial BEMF measurement that are free of spikes in a change of current term of the initial BEMF measurement.

According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head, a sensor, a non-volatile semiconductor storage device, and a controller. The magnetic head performs writing and reading to and from the magnetic disk. The sensor detects a degree of a physical influence applied from an outside. The controller generates a log when a detection value detected by the sensor satisfies a condition for abnormality determination, and stores the log in the non-volatile semiconductor storage device in response to generation of the log.

According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head, a sensor, a non-volatile semiconductor storage device, and a controller. The magnetic head performs writing and reading to and from the magnetic disk. The sensor detects a degree of a physical influence applied from an outside. The controller generates a log when a detection value detected by the sensor satisfies a condition for abnormality determination, and stores the log in the non-volatile semiconductor storage device in response to generation of the log.

A tape drive may calculate the slopes for three successive timing-based-servo marks in a timing-based-servo group. The timing-based-servo marks may be arranged in a one or more M-patterns. The three successive timing-based-servo marks may be across the one or more M-patterns. The tape drive may perform a parabolic fit of a gradient of the slopes. The tape drive may determine whether the gradient is demonstrative of tape-creep.

A temperature measuring unit includes a base including a first face, a second face on a side opposite to the first face, and a first opening portion penetrating the first face and the second face, a support member including a body portion provided on the second face side to overlap with the first opening portion, and a plurality of extending portions extending from the body portion along the second face and overlapping with the second face, and a thermocouple inserted into the first opening portion and including a measuring portion located on the body portion.

A data storage device is disclosed comprising a coarse actuator configured to actuate a first head over a first disk surface and a second head over a second disk surface. A first fine actuator is configured to actuate the first head over the first disk surface, and a second fine actuator is configured to actuate the second head over the second disk surface. A first bias signal is calibrated for the first fine actuator, and a second bias signal is calibrated for the second fine actuator. The first fine actuator is controlled based on the first bias signal and the second fine actuator is controlled based on the second bias signal in order to concurrently access the first disk surface and the second disk surface.

According to one embodiment, a head suspension assembly includes a support plate having a proximal end and a distal end, a wiring member on the support plate and including a metal plate and a wiring board laid on the metal plate, the metal plate including a first joined portion joined to the support plate close to the distal end and a second joined portion joined to the support plate and located on a proximal end side of the support plate, a head mounted on the wiring member, an extendable piezoelectric element mounted on the wiring member, and a damper including a viscoelastic layer and a constraint layer stacked on the viscoelastic layer and attached to the support plate to cover the first joined portion and the second joined portion.

A data storage device is disclosed comprising a voice coil motor (VCM) having a resonance frequency, a first disk surface comprising a first set of servo sectors written at a frequency less than twice the VCM resonance frequency, and a second disk surface comprising a second set of servo sectors circumferentially offset from the first set of servo sectors and written at a frequency less than twice the VCM resonance frequency. An access of the first disk surface is performed by reading at least one of the first set of servo sectors to generate a first position error signal (PES), reading at least one of the second set of servo sectors to generate a second PES, and controlling the VCM based on the first PES and the second PES to position a first head over the first disk surface while accessing the first disk surface.

Provided herein is an apparatus including a disk drive base, wherein the disk drive base includes a first metal composition with a first CTE (coefficient of thermal expansion). A disk drive cover is attached to the disk drive base, wherein the disk drive cover includes a second metal composition with a second CTE that are different from the first metal composition and the first CTE. An arm is connected to a reader and a writer, wherein the arm is coupled to the disk drive base, the reader and the writer are separated by a distance, and the distance affects an MR (magnetoresistive) offset. In response to temperature changes between 0 C. and 60 C., the first material and the second material expand and contract comparably and proportionally. In further response to the temperature changes between 0 C. and 60 C., a change in the MR offset is less than 10% or a preferably defined range of a track pitch on a recording medium attached to the disk drive base.