Patent classifications
G11B5/55
Data storage device attenuating multiple actuator coupling disturbance
A data storage device is disclosed comprising a first actuator configured to actuate a first head over a first disk, and a second actuator configured to actuate a second head over a second disk. The first actuator is controlled based on a first feed-forward seek profile to seek the first head over the first disk, and the second actuator is controlled to position the second head over a second data track on the second disk including to process the first feed-forward seek profile to attenuate a coupling disturbance from the first actuator.
Hysteresis compensation in a disc drive
Systems and methods for compensating for hysteresis in a disc drive are described. In one embodiment, a method may use an inverse hysteresis model to linearize effects of hysteresis of a microactuator in the disc drive. The hysteresis model may be a Coleman-Hodgdon hysteresis model. The hysteresis of the microactuator may be characterized, and the inverse hysteresis model may be based at least in part on the characterization. The inverse hysteresis model may be used to implement a digital filter. The digital filter may be employed in series with the microactuator to linearize the effects of hysteresis.
Determining bit aspect ratios for multiple, independent, actuator storage device
Performance data of two or more actuators of a storage device is determined. The actuators independently move respective two or more heads over one or more disks coupled to a spindle motor. The independent movement of the two or more heads causes coupling therebetween that affects tracking of the two or more heads. Based on the performance data, bit aspect ratios associated with each of the two or more heads are selected that minimize performance impacts due to the coupling.
Loop shaping methods and devices for disturbance observer in servo control systems
An apparatus includes voice coil motor (VCM) control circuitry and microactuator control circuitry. The VCM control circuitry includes a VCM disturbance observer configured to generate a VCM disturbance compensation signal. The microactuator control circuitry includes a microactuator disturbance observer configured to generate a microactuator disturbance compensation signal. The VCM disturbance observer and the microactuator disturbance observer are decoupled from each other.
LOW WEAR DEBRIS POLYOXYMETHYLENE COMPOSITION AND A RAMP MADE OF SUCH POLYOXYMETHYLENE COMPOSITION SUITABLE FOR VARIOUS HDD DESIGNS
A polyoxymethylene composition includes a polyoxymethylene copolymer with 1,3-dioxolane as a comonomer, a wear resistance agent, a nucleating agent, and an antistatic agent. A ramp is made of the polyoxymethylene composition. The ramp and the polyoxymethylene have excellent low-wear-debris property. The low wear debris polyoxymethylene composition can be used to produce a ramp for many different designs of hard disks, such as PMR (perpendicular recording)+TDMR (Two-Dimensional Magnetic Recording), SMR (Shingled Magnetic Recording), HAMR.sup.+ (HAMR (Heat Assisted Magnetic Recording)+SMR+TDMR), BPMR.sup.+ (BPMR (Bit Pattern Media Recording)+SMR+TDMR), and helium-filled hard disk.
Feedforward compensation for multi-actuator hard drives
An apparatus includes a first controller, a second controller, and a coupling compensator. The first controller is configured to generate a first voice coil motor (VCM) control signal in response to a first position error signal. The second controller is configured to generate a second VCM control signal in response to a second position error signal. The coupling compensator is configured to generate a first feedforward correction signal in response to the first VCM control signal. The first feedforward correction signal modifies the second VCM control signal to generate a modified second VCM control signal.
RECALLING FILES STORED ON A TAPE
The time required for recalling the file is reduced when the file is written in a mounted plurality of tapes in comparison to recalling the file when written in a non-mounted plurality of tapes. In the non-mounted state, criteria does not typically exist in order to recall the written file within the plurality of tapes. Embodiments of the present invention provide systems and methods for recalling files based on criteria which considers: the mounted state of a tape; the type of tape; the type of available tape drive; the number of files included in a tape; and the location of the written file in a tape.
RECALLING FILES STORED ON A TAPE
The time required for recalling the file is reduced when the file is written in a mounted plurality of tapes in comparison to recalling the file when written in a non-mounted plurality of tapes. In the non-mounted state, criteria does not typically exist in order to recall the written file within the plurality of tapes. Embodiments of the present invention provide systems and methods for recalling files based on criteria which considers: the mounted state of a tape; the type of tape; the type of available tape drive; the number of files included in a tape; and the location of the written file in a tape.
RECALLING FILES STORED ON A TAPE
The time required for recalling the file is reduced when the file is written in a mounted plurality of tapes in comparison to recalling the file when written in a non-mounted plurality of tapes. In the non-mounted state, criteria does not typically exist in order to recall the written file within the plurality of tapes. Embodiments of the present invention provide systems and methods for recalling files based on criteria which considers: the mounted state of a tape; the type of tape; the type of available tape drive; the number of files included in a tape; and the location of the written file in a tape.
METHOD FOR CORRECTING A MOUNTING POSITION OF A DISK DEVICE ON A RACK
A method for correcting a mounting position of a disk device on a rack, includes performing a normal seek to position a head of the disk device above a target position on the disk, determining that the normal seek has failed, and performing an excitation seek that causes a position of a base supporting the disk to move and reposition the disk. The disk device includes a carriage arm supporting the head, a voice coil motor configured to drive the carriage arm to position the head, the base supporting the magnetic disk, the voice coil motor, and the carriage arm, and a control unit configured to control a current to the voice coil motor to be supplied with a first current profile during the normal seek and with a second current profile during the excitation seek.