Abstract: A broadband through printed circuit board (PCB) for millimeter wave application and methods of manufacture are disclosed. The structure includes a multiple layered body and an opening in the multiple layered body. The structure further includes at least one signal via extending through the opening. The structure further includes ground vias extending through the opening and on opposing sides of the at least one signal via. The structure further includes a ground plate above and below the opening and electrically connected to the ground vias at respective ends. The structure further includes a microstrip signal via above and below the opening and electrically connected to the at least one signal via.

Abstract: A broadband through printed circuit board (PCB) for millimeter wave application and methods of manufacture are disclosed. The structure includes a multiple layered body and an opening in the multiple layered body. The structure further includes at least one signal via extending through the opening. The structure further includes ground vias extending through the opening and on opposing sides of the at least one signal via. The structure further includes a ground plate above and below the opening and electrically connected to the ground vias at respective ends. The structure further includes a microstrip signal via above and below the opening and electrically connected to the at least one signal via.

Abstract: A direct access storage device may handle various disk drive management functions without contemporaneous host computer involvement by buffering commands for the management functions in controller memory. The commands may be read into controller memory from the disk drive on power up or programmed by the host computer. Initially the commands are treated as processes in a blocked state. Operating statistics kept by a supervisor program for the controller are monitored by an event handler, which moves processes to a ready to run state upon occurrence of specified conditions. A dispatcher then moves commands into the direct access storage controller for execution and subsequent return to blocked status.

Abstract: A method and apparatus are provided for servo demodulation in a direct access storage device. A readback signal is sensed from at least one disk surface and locations of positive and negative peaks in the sensed readback signal are detected for providing a detected peak signal. A square wave signal having a period variable with distance between detected locations of positive and negative peaks is generated using the detected peak signal and applied to a servo demodulator in the direct access storage device.

Abstract: A disk drive stores multimedia data in long spiral data tracks. The tracks on opposite surfaces of the disk spiral in opposite directions, so that a track on one surface can be read as the actuator sweeps in, and a track on the opposite surface can be read as the actuator sweeps out. Because the actuator only follows spiral tracks without performing long seek operations, the actuator motor can be reduced in size and stresses on actuator bearings and other parts are reduced. Additionally, due to reduced disturbances associated with seeks, it is possible to follow tracks more closely and therefore reduce the width of individual tracks. Further cost reductions are accomplished by spinning the disks at a slower speed and reducing the size of the spin motor accordingly. Finally, data density can be increased simply because multimedia data does not require the same low error rate as conventional data. Preferably, a group of disk drives optimized for multimedia data is used to form a video-on-demand system.

Abstract: A self servo writing file and method for writing servo patterns in a direct access storage device are provided. First servo information is written on a data storage media at a first crash stop. The transducer heads are moved offset from the written servo information while reading the last written servo information until the detected servo signal equals a predetermined value. Then servo information is written on the data storage media responsive to the detected servo signal equal to the predetermined value. The moving and writing steps are sequentially repeated until a second crash stop is reached. A quad-burst servo amplitude pattern or phase pattern can be used for the servo information. The servo writing method is adapted easily for many different servo options. When the file uses a hybrid servo or sector servo, the other surfaces can be written by duplicating the servo bursts with a high bandwidth servo system of the file.

Abstract: A secondary data storage system for a host computer system includes a disk drive system having a device controller, at least a first magnetic disk and a read/write magnetic transducer positionable with respect to a recording surface of each magnetic disk. A write operation exposes data on adjacent tracks to potential damage if an off track condition occurs to the transducer during a write. A method for controlling write operations through the device controller provides backup of data in tracks adjacent to a target track for the write operation prior to the write operation occurring. The method detects occurrence of events resulting in an off track condition of the magnetic transducer relative to a target track. Occurrence of such an event triggers a determination of damage to the contents of tracks adjacent to the target track and restoration of those tracks. Write operations to the target track are blocked until shock events discontinue.

Abstract: Apparatus and method are provided for servo signal demodulation using a servo processor and a partial-response maximum-likelihood (PRML) data channel in a disk file. A servo burst timing window is identified. Then a plurality of digital samples are detected with the PRML data channel responsive to identifying the servo burst timing window. Sequential sets of the detected digital samples are accumulated by the PRML data channel and transmitted to the servo processor. The digital samples are processed by the servo processor for providing servo phase information that is used to provide servo position information.

Abstract: A laser (10) provides an output beam to an interferometer (12). A portion of the output beam is directed by a beamsplitter to a receiver (18) as a reference beam while the remaining portion of the output beam passes through the beamsplitter and impinges on a plane mirror reflective surface (14a) mounted upon or integrally formed with or upon a surface of a body of interest, such as rotary actuator or arm (14). The arm has a fixed center of rotation O and rotates through an angular range indicated by theta-max. Phi is the angle of incidence of the laser beam with the arm in its original position when theta equals zero. .vertline.OC.vertline. and .vertline.CD.vertline. are distances which locate the intersection point between the arm and the laser beam relative to the center of rotation O when theta equals zero. A corner cube (16) is located at a convergence plane and returns all reflected beams back to the plane mirror and hence to the receiver via the interferometer.