Provided are at least two bearings; an outer shaft having a tubular shape and supporting the bearings at an outer circumferential surface; and an inner shaft housed in the outer shaft with one end extending out from one opening part of the outer shaft. The inner shaft includes a male thread part at least at a portion extending out from the outer shaft.

Provided are at least two bearings; an outer shaft having a tubular shape and supporting the bearings at an outer circumferential surface; and an inner shaft housed in the outer shaft with one end extending out from one opening part of the outer shaft. The inner shaft includes a male thread part at least at a portion extending out from the outer shaft.

A data storage device is disclosed comprising a head actuated over an energy assisted magnetic media comprising a plurality of data tracks, wherein each data track comprises a plurality of data sectors. A write operation to a first data sector is executed by applying a first current to a write coil of the head while the head is over a second data sector preceding the first data sector, wherein the first current comprises a first amplitude. A second current is applied to the write coil while the head is over the first data sector, wherein the second current comprises a second amplitude lower than the first amplitude.

A data storage device includes a ramp configured to support at least one head in the data storage device, and a movement mechanism coupled to the ramp and configured to move the ramp from a first position to a second position by at least one of expansion or contraction of at least a portion of the movement mechanism. The data storage device further includes a ramp motion control module operably coupled to the movement mechanism. The ramp motion control module is configured to provide the movement mechanism with a first control signal that causes the movement mechanism to move the ramp from the first position to the second position. The data storage device additionally includes a latch configured to hold the ramp.

A data storage device includes a ramp configured to support at least one head in the data storage device, and a movement mechanism coupled to the ramp and configured to move the ramp from a first position to a second position by at least one of expansion or contraction of at least a portion of the movement mechanism. The data storage device further includes a ramp motion control module operably coupled to the movement mechanism. The ramp motion control module is configured to provide the movement mechanism with a first control signal that causes the movement mechanism to move the ramp from the first position to the second position. The data storage device additionally includes a latch configured to hold the ramp.

A disk device includes magnetic disks, ramps, suspensions, and magnetic disks. The magnetic disks are arranged above a housing bottom and configured to be rotated around a first rotation axis. The ramps are arranged above the housing bottom. The suspensions are configured to be rotated around a second rotation axis parallel to the first rotation axis, The magnetic heads are mounted on the suspensions, respectively. Each of the suspensions is configured to be rotated around the second rotation axis from a first position above or below one of the magnetic disks to a second position on one of the ramps. The plurality of ramps includes a first ramp and a second ramp that is above the first ramp. An inner end of the second ramp is closer to the first rotation axis than is an inner end of the first ramp.

A disk device includes magnetic disks, ramps, suspensions, and magnetic disks. The magnetic disks are arranged above a housing bottom and configured to be rotated around a first rotation axis. The ramps are arranged above the housing bottom. The suspensions are configured to be rotated around a second rotation axis parallel to the first rotation axis, The magnetic heads are mounted on the suspensions, respectively. Each of the suspensions is configured to be rotated around the second rotation axis from a first position above or below one of the magnetic disks to a second position on one of the ramps. The plurality of ramps includes a first ramp and a second ramp that is above the first ramp. An inner end of the second ramp is closer to the first rotation axis than is an inner end of the first ramp.

According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head, an actuator, a controller, and a ramp. The magnetic head is configured to record data on and reproduce data from the magnetic disk. The actuator is configured to move the magnetic head relative to the magnetic disk. The controller is configured to control the actuator. The ramp is configured to hold the magnetic head. The controller is configured to, in a retract operation for causing the actuator to retract the magnetic head to the ramp, alternate detection of a back electromotive force of the actuator and application of a voltage corresponding to the back electromotive force to the actuator, and skip the detection of the back electromotive force a predetermined number of times in response to an event that the magnetic head moves at a speed outside a predetermined range.

According to one embodiment, a magnetic disk device comprises a magnetic disk, a magnetic head, a monitoring unit, and a control unit. When carrying out write of data to a first track, if an absolute difference between a light output monitored by the monitoring unit at the time of write and a light output monitored last time by the monitoring unit exceeds a predetermined value, the control unit controls a position of a write head and writes data again to the first track or a second track one track before the first track.

A disk device according to one embodiment includes a magnetic disk, a magnetic head, and a flexible printed circuit board. The flexible printed circuit board is electrically connected to the magnetic head. The flexible printed circuit board includes a first layer, a second layer having conductive property, and a third layer having insulation property. The first layer includes a first surface having insulation property. The second layer overlays the first surface, and includes a first conductor and a second conductor spaced from the first conductor. The third layer covers at least a part of the first surface and at least a part of the second layer. The flexible printed circuit board is provided with a first hole that is located between the first conductor and the second conductor with spacing from the second layer and penetrates the third layer.