According to one embodiment, a disk device includes a plurality of recording media each including a recording layer and an actuator assembly including an actuator block rotatably supported around a rotation shaft, a plurality of arms extending from the actuator block, and suspension assemblies respectively attached to the arms and supporting respective magnetic heads. Of the plurality of arms, at least one arm has vibration characteristics different from those of the other arms.

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 disk device includes one or more disks, a base shaft, a bearing shaft, first and second bearing units, first and second actuator assemblies, and a damping member. The bearing shaft has a tubular portion fixed around the base shaft. The first and second bearing units are attached around the bearing shaft and aligned in an axial direction of the bearing shaft. The first and second actuator assemblies are coupled to the first and second bearing units, respectively. The damping member is provided between an outer circumferential surface of the base shaft and an inner circumferential surface of the tubular portion of the bearing shaft.

A rotor includes a rotor hub including a through-hole to which the shaft is fixed. An upper end and a lower end of an opposing region where an outer peripheral surface of the shaft and an inner peripheral surface of the through-hole oppose each other in a radial direction are respectively provided with an upper gap portion and a lower gap portion opposing each other through a space in the radial direction. The upper gap portion and the lower gap portion each include a bottom portion extending in a direction intersecting the center axis and a peripheral wall portion connected to a radial outer edge of the bottom portion and extending along the center axis.

Motion of a first actuator in a multi-actuator drive is prevented from affecting a second actuator in the drive or from being affected by the second actuator. A coupling coordinator generates a hold command for the second actuator based on an operation to be carried out using the first actuator, where the hold command is generated before commands to carry out the operation are issued. The hold command may cause an aggressor actuator in the drive to halt a disturbance-generating operation being performed by the aggressor actuator or delay initiation of such an operation that is to be performed by the aggressor actuator. The hold command may cause a victim actuator in the drive to pause the execution of a sensitive operation being performed by the victim actuator or delay initiation of such an operation that is to be performed by the victim actuator.

A motor includes a rotor, a stator, a shaft, a base part, a hole part, a connector, and a metal connection portion. The rotor is rotatable about the axial direction. The stator radially opposes the rotor. The shaft extends axially along the central axis and supports the rotor. The base part is disposed on axial one side relative to the stator, and radially expands from the shaft. The hole part axially penetrates the base part. The connector covers the hole part when viewed from the axial direction. The metal connection portion connects the connector to the base part. The metal connection portion is disposed between the base part and the connector in the axial direction, and surrounds the hole part when viewed from the axial direction.

A spindle motor is provided, the motor comprising: a base plate, a PCB on the base plate, a bearing assembly arranged on the base plate, a stator coupled to a periphery of the bearing assembly, a rotor rotationally coupled to the bearing assembly, the rotor including a yoke and a magnet, and a rotation shaft rotationally coupled to the bearing assembly. The base plate includes a planar portion and a protruding portion arranged along with a periphery of the yoke, the protruding portion being apart from the yoke. The base plate is partially covered with the PCB in a region where the stator is arranged. And, a height from the planar portion to an upper surface of the protruding portion is smaller than a height from the planar portion to a lower surface of the periphery of the yoke.

According to one embodiment, a magnetic disk device includes a power supply, a magnetic disk, a magnetic head, a communication unit that is communicable with a host computer and transmits a signal to the host computer at a first interval, a power supply monitor, a volatile memory that stores data related to read/write processing on the magnetic disk by the magnetic head, a non-volatile memory, and a controller that controls the communication unit to start processing of backing up the data stored in the volatile memory to the non-volatile memory and transmit the signal at a second interval longer than the first interval if power supplied from the power supply is detected to be disconnected based on monitoring of the power supply monitor.

A spindle motor configured to be used for a hard disk drive device with a gas having a density lower than a density of air sealed in an internal space includes a rotor magnet. The rotor magnet has a radial thickness of 1.0 to 1.4 mm and a density of 5.6 to 6.0 g/cm.sup.3.

A spindle motor includes a shaft fixed to a base portion and a hub rotatably supported by the shaft. The hub is a cold-forged product made of low-carbon steel having a carbon content of 0.23 mass % or less.