An exemplary data storage device includes an actuator arm assembly, a top guide rail, a bottom guide rail, and a first ball bearing. The actuator arm assembly includes a first post defining a pivot axis that is inclined between about 5 degrees and about 25 degrees from a horizontal plane defined by a data storage disk surface. The top guide rail includes a first rolling surface that is parallel to the pivot axis. The bottom guide rail is spaced from the top guide rail and includes a second rolling surface that is parallel to the first rolling surface. The first ball bearing includes a first inner race and a first outer race, the first inner race surrounding the first post, and the first outer race in contact with the first rolling surface or the second rolling surface. An exemplary method of assembling a data storage device is also described.

A hard disk drive includes multiple actuator assemblies, each of which includes a head-stack assembly (HSA) including an end-arm to which a single head-gimbal assembly (HGA) is coupled, where this end-arm is configured with a notch along one side and a triangular or quadrilateral-shaped through-hole at a root-side of the end-arm, and where the HSA further includes a plurality of other end- and inner-arms to each of which two HGAs are coupled and none of which have a through-hole near their root. The single-HGA end-arm may be further configured with an outer damper having a through-hole coincident with the end-arm through-hole, such that the through-hole of the end-arm is not covered by this damper, and an inner damper having no through-hole, such that the through-hole of the end-arm is covered by this damper. Gains are thereby better matched across all HGAs for problematic arm and system modes.

A motor driver circuit includes: a current detection circuit configured to generate a current detection signal according to a drive current of a motor as an object to be driven; a first amplifier configured to amplify the current detection signal; a second amplifier configured to multiply a voltage across the motor by a gain smaller than 1 and output the multiplied voltage; and a third amplifier configured to generate a back electromotive force detection signal according to a difference between an output of the first amplifier and an output of the second amplifier.

A first tone is written at a first frequency to outer tracks that surround an inner track of a magnetic recording medium. A second tone is written at a second frequency different from the first frequency to the inner track. The first and second frequencies are both lower than a frequency of an AC erase signal. A crosstrack profile of the inner track is determined based on reading amplitude of the second frequency via the read/write head.

A data storage device includes a stack of a plurality of disks, first and second arms, first and second heads, first and second linear drivers and an elevator. Each of the plurality of disks includes a read/write surface. The first arm has a first head end that is movable relative to the stack. The first head is configured to interact with a selected one of the read/write surfaces. The first linear driver is configured to move the first arm along a first straight line in a x-y plane defined by the one of the read/write surfaces. The elevator is configured to move the first arm in a z direction. The second arm has a second head end that is movable relative to the stack and supports the second head. The second linear driver is configured to move the second arm along a second straight line in the x-y plane.

A hard disk drive includes multiple actuator assemblies, each of which includes a head-stack assembly (HSA) including an end-arm to which a single head-gimbal assembly (HGA) is coupled, where this end-arm is configured with a notch along one side and a triangular or quadrilateral-shaped through-hole at a root-side of the end-arm, and where the HSA further includes a plurality of other end- and inner-arms to each of which two HGAs are coupled and none of which have a through-hole near their root. The single-HGA end-arm may be further configured with an outer damper having a through-hole coincident with the end-arm through-hole, such that the through-hole of the end-arm is not covered by this damper, and an inner damper having no through-hole, such that the through-hole of the end-arm is covered by this damper. Gains are thereby better matched across all HGAs for problematic arm and system modes.

A recording head has a magnetic write transducer having a first crosstrack width operable to write a single track of data at a time to a magnetic disk. The recording head also has a magnetic erase transducer separate from the magnetic write transducer. The magnetic erase transducer has a second crosstrack width operable to simultaneously erase multiple tracks of data at from the magnetic disk

A self servo-write process in performed on two or more recording surfaces simultaneously. In a dual-stage servo system, a first fine positioning servo system that includes a first microactuator independently controls the position of a first read/write head over a first recording surface of a hard disk drive, while a second fine positioning servo system that includes a second microactuator independently controls the position of a second read/write head over a second recording surface of the hard disk drive.

A brake crawler for an elevator-type hard disk drive generally includes a first and second set of clamp arms vertically arranged, each of the first and second sets of clamp arms being capable of exerting a clamping force on a shaft or slider via activation or deactivation of an actuator element associated with each set of clamp arms. The brake crawler further includes an actuator element disposed between the first and second set of clamp arms which allows for movement of the first set of clamp arms away from the second set of clamp arms upon a change in state of the actuator element. Via a specific sequence of activating and deactivating various of the actuator elements associated with the brake crawler, the brake crawler is capable of inch worm-type movement up and down the shaft.

A voice coil motor yoke having a magnet bonding surface includes an annular groove inside a bonding region on the magnet bonding surface, the bonding region having substantially the same shape as a contour of a magnet to be bonded on the magnet bonding surface of the yoke. A region surrounded by the annular groove on the magnet bonding surface is an adhesive application region. A voice coil motor includes: a pair of the voice coil motor yokes; an adhesive applied to the adhesive application region of each of the pair of yokes; and a pair of rare earth magnets bonded via the adhesive to the bonding region of each of the pair of yokes.