Abstract: A tape drive (232) that receives a tape cartridge (42) having a tape (256) comprises a tape head (280) and a control system (270). The tape head (280) transfers data between the tape drive (232) and the tape (256). The control system (270) utilizes linear parameterization to control the position of the tape head (280) relative to the tape (256). The control system (270) can include a compensator (J) and a filter (Q). The compensator (J) is a combination of the information contained in a nominal control system (370A) and the information contained in a model of the servo system (370B). The model of the servo system (370B) estimates system disturbances that affect the tracking ability of the control system (270). The filter (Q) filters the estimated system disturbances to generate a filtered system disturbance signal. The filtered system disturbance signal is then used to adjust the output of the compensator (J).

Abstract: A tape drive (232) that receives a tape cartridge (42) having a tape (256) comprises a tape head (280) and a control system (270). The tape head (280) transfers data between the tape drive (232) and the tape (256). The control system (270) utilizes linear parameterization to control the position of the tape head (280) relative to the tape (256). The control system (270) can include a compensator (J) and a filter (Q). The compensator (J) is a combination of the information contained in a nominal control system (370A) and the information contained in a model of the servo system (370B). The model of the servo system (370B) estimates system disturbances that affect the tracking ability of the control system (270). The filter (Q) filters the estimated system disturbances to generate a filtered system disturbance signal. The filtered system disturbance signal is then used to adjust the output of the compensator (J).

Abstract: Some embodiments of the present invention provide a system that attenuates noise from a fan exhaust of a computer system. During operation, the system monitors the noise from the fan exhaust and calculates a frequency spectrum of the noise from the monitored noise. Next, the system generates an antiphase spectrum from the frequency spectrum and generates a flow of air which exhibits a property of the antiphase spectrum. Finally, the system directs the flow of air into the fan exhaust so that the noise is attenuated by a reduction of turbulence in the fan exhaust by the flow of air.

Abstract: A method of quantifying a shape of a surface includes measuring an elevation (z) of the surface at a plurality of locations in an x-y plane of the surface. The measurement data is fit to a series expansion in terms of one or more base functions that include a series expansion fit. A vector of shape coefficients are calculated from the series expansion fit. A vector of shape coefficients are output.

Abstract: Some embodiments of the present invention provide a system that assures stability of the speed of a cooling fan in a computer system. During operation, a temperature of the computer system, an ambient temperature, and a current fan speed for the cooling fan are monitored. Next, a validated ambient temperature based on parameters including the temperature of the computer system, the ambient temperature, and the current fan speed is computed. Then, a control signal is generated in response to the validated ambient temperature, and the control signal is sent to the cooling fan to assure stability of the fan speed of the cooling fan.

Abstract: A method for quantifying a shape of a surface comprising: measuring an elevation (z) of the surface at a plurality of locations in an x-y plane of the surface comprising measurement data; performing a fit of the measurement data to a series expansion in terms of one or more base functions comprising a series expansion fit; calculating a vector of shape coefficients from the series expansion fit; and outputting the vector of shape coefficients.

Abstract: Some embodiments of the present invention provide a system that attenuates noise from a fan exhaust of a computer system. During operation, the system monitors the noise from the fan exhaust and calculates a frequency spectrum of the noise from the monitored noise. Next, the system generates an antiphase spectrum from the frequency spectrum and generates a flow of air which exhibits a property of the antiphase spectrum. Finally, the system directs the flow of air into the fan exhaust so that the noise is attenuated by a reduction of turbulence in the fan exhaust by the flow of air.