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.

A data storage device is disclosed comprising a disk comprising servo data, a spindle motor configured to rotate the disk, and a head actuated over the disk. A position error signal (PES) is generated based on the servo data, and the head is actuated over the disk based on the PES. While swinging a speed of the spindle motor, the swinging is disabled based on the PES.

A data storage device is disclosed comprising a head actuated over the disk. A first notch filter is calibrated at a first temperature, and a second notch filter is computed for a second temperature based on the first notch filter and a first delta temperature between the first temperature and the second temperature. The second notch filter is computed by transforming a continuous-time transfer function of the first notch filter adjusted by the first delta temperature into a discrete-time transfer function of the second notch filter.

In a two-dimensional magnetic recording (TDMR) system, a first finite impulse response (FIR) filter processes data read from a track of a magnetic medium by a first head using first filter tap values determined a priori independently of a second head. A second FIR filter processes data read from a track by the second head using second filter tap values determined a priori independently of the first head. An off-track detector detects whether one or more of the first and second heads is off of the tracks being read. A gain controller controls gains for the first and second FIR filters based on whether one or more of the first and second heads is off of the tracks being read.

Various illustrative aspects are directed to a data storage device, comprising one or more disks; an actuator mechanism configured to position one or more heads proximate to one or more disk surfaces of the one or more disks; and one or more processing devices, comprising an actuator mechanism control system configured for controlling the actuator mechanism. The one or more processing devices are configured to: output a multi-rate excitation to at least one multi-rate notch filter of the actuator mechanism control system; detect a frequency response of the actuator mechanism in response to the multi-rate excitation; and calibrate the at least one multi-rate notch filter of the actuator mechanism control system, based at least in part on the detected frequency response of the actuator mechanism.

Various illustrative aspects are directed to a data storage device, comprising one or more disks; an actuator mechanism configured to position one or more heads proximate to one or more disk surfaces of the one or more disks; and one or more processing devices, comprising an actuator mechanism control system configured for controlling the actuator mechanism. The one or more processing devices are configured to: output a multi-rate excitation to at least one multi-rate notch filter of the actuator mechanism control system; detect a frequency response of the actuator mechanism in response to the multi-rate excitation; and calibrate the at least one multi-rate notch filter of the actuator mechanism control system, based at least in part on the detected frequency response of the actuator mechanism.

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 drive includes a notch filter, a parameter storage unit and a computation unit, when the sampling period changes from a first sampling period to a second sampling period, the computation unit computes a damping ratio parameter related to the damping ratio in a second set of parameters at the second sampling period, based on a first absolute value at a first angular frequency of a first transfer function computed from a first set of parameters at the first sampling period and a second absolute value at the first angular frequency of a second transfer function computed from the first set of parameters at the second sampling period, and the notch filter is set with the second set of parameters at the second sampling period is computed.

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 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..