A data storage device comprises a lead actuator that actuates a first read-write head over a first disk and a support actuator that actuates a second read-write head over a second disk. A spindle motor rotates the first and second disks. In response to an emergency power off (EPO) event, a processing device retracts and parks the actuators using an internal supply voltage generated from a back electromotive force (BEMF) voltage of the spindle motor, and brakes the spindle motor. The spindle motor is not braked until both the lead and support actuators have been retracted and parked.

An approach to a reduced-head hard disk drive (HDD) involves an actuator elevator subsystem that includes a ball screw cam assembly with an axial flux permanent magnet (AFPM) motor affixed to a cam screw to drive rotation of the screw, which drives translation of an actuator arm assembly so that a corresponding pair of read-write heads can access different magnetic-recording disks of a multiple-disk stack.

A device disclosed herein includes an upper shape memory alloy (SMA) wire, a lower SMA wire, a flexure having an opening, and a spring configured within the flexure opening, wherein the lower SMA wire, and the flexure are attached at one end to an anchor and at another end to a pin.

According to one embodiment, a magnetic disk device includes a first disk having a first user data region and a first system area, a second disk having a second user data region and a second system area, a first head that writes data to the first disk, a second head that writes data to the second disk, a first actuator having the first head, a second actuator having the second head, a first controller that controls the first disk, the first head, and the first actuator, and a second controller that controls the second disk, the second head, and the second actuator, wherein the first controller records first information related to the first head and the first disk in the second system area.

A hard disk drive includes a drive case and a cover plate, the storage media platers and a spindle, the recording heads and actuators, the connection port, the control logic board and one or more voice coil motor, where the actuators are operated via a voice coil motor; wherein the voice coil motor magnets comprise of a pair of composite permanent magnets on both sides of the voice coil, where each piece of composite permanent magnet comprising: a first core magnet M1, a cladding magnet Mc12 and a second core magnet M2; the magnetization direction of M1 and M2 are opposite to each other; the magnetization direction of Mc12 is substantially perpendicular to the magnetization direction of M1 and M2; the ratio of the width of Mc12 to the thickness or the height of Mc12 is 4:1 or less as seen from the back view.

A hard disk drive includes a drive case and a cover plate, the storage media platers and a spindle, the recording heads and actuators, the connection port, the control logic board and one or more voice coil motor, where the actuators are operated via a voice coil motor; wherein the voice coil motor magnets comprise of a pair of composite permanent magnets on both sides of the voice coil, where each piece of composite permanent magnet comprising: a first core magnet M1, a cladding magnet Mc12 and a second core magnet M2; the magnetization direction of M1 and M2 are opposite to each other; the magnetization direction of Mc12 is substantially perpendicular to the magnetization direction of M1 and M2; the ratio of the width of Mc12 to the thickness or the height of Mc12 is 4:1 or less as seen from the back view.

According to one embodiment, a magnetic disk device includes a first disk having a first user data region and a first system area, a second disk having a second user data region and a second system area, a first head that writes data to the first disk, a second head that writes data to the second disk, a first actuator having the first head, a second actuator having the second head, a first controller that controls the first disk, the first head, and the first actuator, and a second controller that controls the second disk, the second head, and the second actuator, wherein the first controller records first information related to the first head and the first disk in the second system area.

Systems and methods are disclosed for calibrating actuators in a multi-stage servo system. In certain embodiments, a method may comprise performing a calibration process on a multi-stage actuated servo system, including simultaneously injecting voltage injections into multiple microactuators of the servo system, measuring a resulting position error signal (PES), and determining gain settings for each of the multiple microactuators based on the PES. Multiple microactuators can therefore be calibrated during a single-injection calibration operation.

A data storage device is disclosed comprising a voice coil motor (VCM) configured to actuate a head over a disk. The data storage device further comprises control circuitry comprising a digital current control loop including a windowed delta-sigma analog-to-digital converter (ADC) configured to control the VCM. A vibration of the data storage device is measured, and at least one of a gain or a window of the windowed delta-sigma ADC is configured based on the measured vibration.

According to one embodiment, there is provided a hard disk drive including a first recording surface, a second recording surface, a first magnetic head, a first actuator and a second actuator that move the first magnetic head, a second magnetic head, a third actuator and a fourth actuator that move the second magnetic head, a fifth actuator that moves the second actuator and the fourth actuator, a drive circuit that implements at least one of a first mode in which the second actuator and the fourth actuator operate differently from each other or a second mode in which the first and third actuators operate differently from each other, and a controller that controls the drive circuit.