Abstract: A tape drive configured to accurately position a head actuator in the presence of physical disturbances is disclosed. The tape drive includes a track-follow controller to position a head actuator over data tracks on magnetic tape. The tape drive further includes a disturbance observer configured to estimate a vibration disturbance and output a compensation signal to assist the track-follow controller to accurately position the head actuator over the data tracks in the presence of vibration. When estimating the vibration disturbance, the disturbance observer takes into account vibration frequency characteristics, such as frequency characteristics derived from a vibration specification associated with the tape drive, or frequency characteristics derived from known vibration disturbances experienced by the tape drive. A corresponding method is also disclosed.

Abstract: A maximum velocity is dynamically determined during a tape drive operation to obtain a statistical standard deviation of a position error signal (PES) that yields an amount of stopwrite (SW) operations that avoids backhitching. The tape velocity is adjusted to the maximum velocity.

Abstract: A magnetic tape drive has a drive system to move a magnetic tape longitudinally; servo head(s) for reading servo band information from a magnetic tape as the magnetic tape is moved longitudinally; a magnetic tape read write head configured to read and to write the magnetic tape, having a data write width (w) greater than a normal shingled track pitch width (p) of the magnetic tape; an actuator system for positioning the read write head laterally; and a control. The magnetic tape drive stores an overwrite erase format of non-shingled track pitch longitudinal pattern(s) whose pitch is greater than the normal shingled track pitch width (p); and, the control, in response to activation of overwrite erasure of the tape drive, operates the actuator system and the magnetic tape read write head to write non-data to magnetic tape in the stored overwrite erase format.

Abstract: An apparatus for controlling an electric motor is provided. A plurality of switches is provided for controlling a direction of current through motor coils of the electric motor. A brushless motor control circuit is connected to each of the plurality of switches. Responsive to a request to adjust one of an angular velocity and an angular acceleration of the electric motor, the plurality of switches are activated to place the motor coils in a predetermined configuration to maximize torque or reduce a total back electromotive force (BEMF) from the motor coils.

Abstract: In accordance with the present invention, a method of operating a magnetic tape drive, a magnetic tape drive and a servo control system are provided for obtaining and maintaining velocity control in a magnetic tape drive. In one embodiment, a method is provided for operating a magnetic tape drive. The tape drive includes a plurality of DC motors, and each DC motor has a plurality of Hall sensors. The DC motors are under the control of a servo system which is configured to read location information from the magnetic tape, and compute a primary tape velocity from the location information, and sense a secondary and tertiary velocity signal and compute a tape velocity based on one of the sensed secondary velocity signal and tertiary velocity. The method includes detecting if the primary velocity location information is available. In response to detecting that the primary velocity location information is available the primary velocity is employed to control the servo system.

Abstract: A tape movement constraint for a tape drive system, comprises a tiltable tape roller bearing having a grooved surface adapted to contact and engage a surface of the tape as the roller barrel rotates, and an actuator adapted to pivot the roller bearing surface when the actuator is actuated, to control the lateral position of a tape. In operation, in one embodiment, a roller barrel of the tiltable roller bearing is biased in a first position on a pivot axis, using magnetic attraction between a movable magnet and a return path structure of magnetically permeable material. The roller barrel is pivoted on the pivot axis by conducting current through a fixed coil to generate a magnetic field which is conducted by the return path structure to interact with the magnetic field of the magnet. Other embodiments are described and claimed.

Abstract: Dynamic reconfiguration-switching of motor windings is optimized between winding-configurations. Acceleration is traded off in favor of higher velocity upon detecting an electric motor is at an optimal angular-velocity for switching to an optimal lower torque constant and voltage constant. The total back electromotive force (BEMF) is prohibited from inhibiting further acceleration to a higher angular-velocity.

Abstract: A tape movement constraint for a tape drive system, comprises a tiltable tape roller bearing having a grooved surface adapted to contact and engage a surface of the tape as the roller barrel rotates, and an actuator adapted to pivot the roller bearing surface when the actuator is actuated, to control the lateral position of a tape. In operation, in one embodiment, a roller barrel of the tiltable roller bearing is biased in a first position on a pivot axis, using magnetic attraction between a movable magnet and a return path structure of magnetically permeable material. The roller barrel is pivoted on the pivot axis by conducting current through a fixed coil to generate a magnetic field which is conducted by the return path structure to interact with the magnetic field of the magnet. Other embodiments are described and claimed.

Abstract: Dynamic reconfiguration-switching of motor windings in an electric motor in an electric vehicle is optimized between winding-configurations. Acceleration is traded off in favor of higher velocity upon detecting the electric motor in the electric vehicle is at an optimal angular-velocity for switching to an optimal lower torque constant and voltage constant. The total back electromotive force (BEMF) is prohibited from inhibiting further acceleration to a higher angular-velocity.

Abstract: Dynamic reconfiguration-switching of motor windings is optimized between winding-configurations. Acceleration is traded off in favor of higher velocity upon detecting a tape storage drive is at an optimal angular-velocity for switching to an optimal lower torque constant and voltage constant. The total back electromotive force (BEMF) is prohibited from inhibiting further acceleration to a higher angular-velocity.

Abstract: Dynamic reconfiguration-switching of motor windings is optimized between winding-configurations. Acceleration is traded off in favor of higher velocity upon detecting a brushless DC motor is at an optimal angular-velocity for switching to an optimal lower torque constant and voltage constant. The total back electromotive force (BEMF) is prohibited from inhibiting further acceleration to a higher angular-velocity.

Abstract: A calculation function, which optimizes a dynamic reconfiguration-switching of motor windings between winding-configurations, is dynamically configured. Acceleration is traded off in favor of higher velocity upon detecting the electric motor is at an optimal angular-velocity for switching to an optimal lower torque constant and voltage constant. The total back electromotive force (BEMF) is prohibited from inhibiting further acceleration to a higher angular-velocity.

Abstract: An apparatus for controlling a wheel motor is provided. A plurality of switches is provided for controlling a direction of current through motor coils of the wheel motor. A brushless motor control circuit is connected to each of the plurality of switches. Responsive to a request to adjust one of an angular velocity and an angular acceleration of the wheel motor, the plurality of switches are activated to place the motor coils in a predetermined configuration to maximize torque or reduce a total back electromotive force (BEMF) from the motor coils.

Abstract: In one embodiment, a tape movement constraint for a tape drive system, comprises a tiltable tape roller bearing having a roller barrel biased in a first position on a pivot axis, using magnetic attraction between a movable magnet and a return path structure of magnetically permeable material. The roller barrel is pivoted on the pivot axis by conducting current through a fixed coil to generate a magnetic field which is conducted by the return path structure to interact with the magnetic field of the magnet. At least a portion of any air bearing between the moving tape and the barrel surface is quenched using grooves formed in the barrel surface. Other embodiments are described and claimed.

Abstract: A method to position a head module, where the head module comprises at least one servo element and a plurality of data elements, where the servo element and each of the plurality of data elements can detect a servo signal, wherein the method includes moving a sequential information storage medium having a servo band encoded therein across the head module and detecting the servo band using the at least one servo element or any one of the plurality of data elements.

Abstract: A sequential information storage medium, comprising a plurality of servo patterns encoded lengthwise thereon, wherein each servo pattern encodes at least one LPOS bit and comprises a width less than 187 microns.

Abstract: A method to position a head module, where the head module comprises at least one servo element and a plurality of data elements, where the servo element and each of the plurality of data elements can detect a servo signal, wherein the method includes moving a sequential information storage medium having a servo band encoded therein across the head module and detecting the servo band using the at least one servo element or any one of the plurality of data elements.

Abstract: A sequential information storage medium, comprising a plurality of servo patterns encoded lengthwise thereon, wherein each servo pattern encodes at least one LPOS bit and comprises a width less than 187 microns.

Abstract: An alternative time interval is taken of a timing based servo band to determine lateral position of a servo read head. The servo band is arranged in a sequence bursts with non-parallel servo stripes in sequentially adjacent sub-frames of a linear tape. The timing intervals comprise at least a first time interval (A) between a first pair of non-parallel servo stripes of a sub-frame; and an alternative time interval (C) between a pair of non-parallel servo stripes intermediate the first time intervals (A), the alternative interval servo stripes of sequentially adjacent sub-frames comprising a second servo stripe of the first pair, and a first servo stripe of a sequentially succeeding first pair. Position signals are ratios involving the first and second time intervals.

Abstract: The method employs a servo system for positioning a head laterally to follow lateral motion of a longitudinal tape having longitudinal defined servo track(s), the servo system comprising a servo element configured to sense lateral position of the head with respect to an acquired servo track, a fine actuator configured to translate the head laterally with respect to the longitudinal tape, and a position error signal loop to operate the fine actuator to translate the head laterally to reduce position error. If the servo element is positioned away from the defined servo track(s), a continuous position error offset signal is applied to the fine actuator in a direction towards the defined servo track(s), whereby the fine actuator translates the head in accordance with the continuous position error offset signal; and, in response to the servo system acquiring the defined servo track(s), the continuous position error offset signal is discontinued.