The invention generally relates to hard disk drives with a disk and a read/write head, and methods for preventing contact between the disk and the read/write head. The hard disk drive includes a z-axis actuator configured to control movement of the read/write head, and to prevent contact between the read/write head and the disk, based on signals from a controller that indicate when the distance between the read/write head and the disk are outside a predetermined range, such as between 0 and 10.0 nm.

According to one embodiment, a magnetic head includes first and second magnetic poles, a conductive part, an element part, and first to fourth terminals. The conductive part is electrically insulated from the first and second magnetic poles. The first and second terminals are electrically connected to the conductive part. The element part is provided between the first and second magnetic poles and electrically connected to the first and second magnetic poles. The element part is conductive. The third terminal is electrically connected to the first magnetic pole. The fourth terminal is electrically connected to the second magnetic pole. A first magnetic pole temperature in a first state is higher than a second magnetic pole temperature of the second magnetic pole in the first state. A first current is supplied between the first and second terminals in the first state.

An exemplary data refresh method disclosed herein reading data into volatile memory from a first storage region using a read element controlled by a first actuator assembly and writing the data from the volatile memory to a second storage region using a write element controlled by a second actuator assembly, where the first actuator assembly and the second actuator assembly are configured to receive data from control circuitry via independent read/write communication channels.

A magnetic disk device includes a magnetic head that writes data on and reads data from the magnetic disk, and a controller circuit. The controller circuit is configured to control a gap between the magnetic head and the magnetic disk, and select one of two or more gap values for the fly height, based on a write location in the magnetic disk of data to be written by the magnetic head.

A magnetic disk device includes a magnetic head that writes data on and reads data from the magnetic disk, and a controller circuit. The controller circuit is configured to control a gap between the magnetic head and the magnetic disk, and select one of two or more gap values for the fly height, based on a write location in the magnetic disk of data to be written by the magnetic head.

According to one embodiment, a magnetic disk device includes an actuator assembly including an actuator block including a rotatable bearing unit, a plurality of heads movably supported by the actuator assembly, a first sensor provided to the actuator block, and a second sensor provided at a position different from the first sensor.

Apparatus and method for disturbance rejection in a control system. In some embodiments, a controller is adapted to position a control object. A disturbance observer generates a disturbance compensation value which is applied to reduce position error resulting from application of mechanical disturbance to the control object. The disturbance observer includes an adaptive filter with at least one dead zone providing a pass-through response with a scalar gain of less than one.

Disclosed herein is a magnetic storage device that comprises a suspension arm co-movably fixed to a carriage arm. The suspension arm comprises a slider attachment side and at least one first electrical contact pad on the slider attachment side. The suspension arm also comprises a slider co-movably fixed to the suspension arm. The slider comprises a suspension attachment side, a non-head side facing the suspension arm and intersecting the suspension attachment side at a first slider edge of the slider, a head side facing away from the suspension arm, and at least one electrical contact component on the suspension attachment side up to the first slider edge. At least one solder weldment is directly coupled to the at least one first electrical contact pad and the at least one electrical contact component. Additionally, a read-write head is coupled to the head side of the slider.

Embodiments of disk drive head suspensions are described that include a spring metal layer. The spring metal layer includes a base region, support arms extending from the base region, and a slider mounting region. The slider mounting region includes a proximal portion, a distal portion, and a pair of motor openings. The motor openings are configured to receive motors such that the longitudinal axes of the motors are non-parallel with the longitudinal axis of the slider mounting region. The suspensions include traces that include a base portion on the base region of the spring metal layer, a spring metal-unsupported portion extending from the base region to the slider mounting region, and a slider mounting portion extending from the spring metal-unsupported portion onto the slider mounting region. And, the suspensions include an insulating layer between portions of the spring metal layer and the conductor layer.

According to one embodiment a magnetic disk device, includes a disk which includes a plurality of servo sectors radially extending in a radial direction and being discretely disposed with a gap in a circumferential direction, a head which writes data to the disk and reads data from the disk, and a controller which writes a plurality of pieces of correction data with respect to a repeatable run-out of the disk to a plurality of first sectors disposed between the servo sectors in a first region, and writes the pieces of correction data to a plurality of second sectors disposed between the servo sectors in a second region different from the first region.