HDDs including multiple heads driven by separate actuator spindles can read from or write to one or more platters simultaneously. Simultaneous active heads can be used to increase data rate or for other purposes. The multiple independently-actuated heads can access the same platter or different platters and may be moved across an associated platter surface in a number of different ways. However, multiple independently operating actuators may lead to mechanical coupling between the actuators. For example, as certain resonant frequencies, the movement of one actuator arm may cause unacceptable movement of another actuator arm within the HDD. This mechanical coupling can have detrimental effects on the HDD. The disclosed coupling observer and disable systems detect and mitigate detrimental effects of mechanical coupling between the independently operated actuators.

A technique for swinging swing arms stably by reducing vibrations of bearing units due to resonance in rolling bearings is provided. A pivot assembly bearing device 1 includes a shaft 10 extending in an axis Y1 direction, and an upper bearing unit 20 and a lower bearing unit 60 that are provided along the axis Y1 direction of the shaft 10. A natural frequency of the upper bearing unit 20 and a natural frequency of the lower bearing unit 60 in the axis Y1 direction of the shaft 10 differ from each other.

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.

According to one embodiment, a disk device includes a plurality of magnetic disks, a casing, a column, a rotary component, and a screw. The casing includes a base having an inner space in which the plurality of magnetic disks is accommodated, and a first cover attached to the base to close the space. The column with a screw hole, is located in the space and is attached to the base by being fitted into a recess formed in the base. The rotary component is located in the space, surrounds the column, and is configured to rotate about the column. The screw is fitted into the screw hole through the first cover.

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 from the magnetic disk.

According to one embodiment, a disk device includes a plurality of magnetic disks, a casing, a column, a rotary component, and a screw. The casing includes a base having an inner space in which the plurality of magnetic disks is accommodated, and a first cover attached to the base to close the space. The column with a screw hole, is located in the space and is attached to the base by being fitted into a recess formed in the base. The rotary component is located in the space, surrounds the column, and is configured to rotate about the column. The screw is fitted into the screw hole through the first cover.

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.

An actuator pivot shaft assembly for a multi-actuator data storage device may include one or more annular grooves extending radially inward from an outer surface of the pivot shaft, thereby desirably weakening or structurally decoupling the shaft between the actuators, to assist with inhibiting transmission of vibration between the actuators during operation. The shaft assembly may further include an elastomeric damper positioned within the annular groove(s), to damp transmission of vibrational forces between the actuators through the shared shaft.

A disk drive including multiple magnetic recording disks and at least one read/write head, wherein the disk drive includes a rotatable center block having a vertical axis and a mounting member, a first motor attached to the center block for rotating the center block about the vertical axis, a vertical threaded rod positioned in the mounting member, a second motor moveable along the vertical threaded rod, at least one head suspension arm extending outwardly from the second motor, and at least one read/write head mounted to a distal end of one of the arms. The disk drive further includes multiple disks in a stack, wherein at least one of the arms is vertically moveable along the vertical threaded rod by the second motor to position the at least one read/write head in a position to access data on one of the disk surfaces of the plurality of disks.

A disk drive including multiple magnetic recording disks and at least one read/write head, wherein the disk drive includes a rotatable center block having a vertical axis and a mounting member, a first motor attached to the center block for rotating the center block about the vertical axis, a vertical threaded rod positioned in the mounting member, a second motor moveable along the vertical threaded rod, at least one head suspension arm extending outwardly from the second motor, and at least one read/write head mounted to a distal end of one of the arms. The disk drive further includes multiple disks in a stack, wherein at least one of the arms is vertically moveable along the vertical threaded rod by the second motor to position the at least one read/write head in a position to access data on one of the disk surfaces of the plurality of disks.