Abstract: Impellers are used in the pull tray of a failure tolerant cooling system and are isolated from each other by baffles, so that each impeller has its own exhaust air flow path with an predetermined airflow resistance. The exhaust airflow resistance is sufficiently low that the associated impeller can exhaust enough air to provide sufficient airflow over the components during normal operation. In particular, the airflow is sufficient so that if a fan in the push tray fails, the pressure drop created by the impellers in the pull tray is sufficient to draw air through the space occupied by the failed fan. However, the exhaust airflow resistance for each impeller in the pull tray is sufficiently high that, if an impeller fails, the resistance limits the amount of air that the remaining impellers can pull in through the failed impeller opening, thereby enabling the airflow delivered by the fans in the push tray to continue to be distributed evenly across the components.

Abstract: A method and apparatus for partitioning network data services among multiple subscribers uses information stored in several tables to define a plurality of independent networks where each independent network comprises a set of access ports and a unique set of destination addresses and is logically separate from all other independent networks so that no information can pass from one independent network to another independent network. When a subscriber makes a request to use an independent network, a subscriber key that is based on the subscriber identity and the network access port is used to determine whether the subscriber has permission to use the independent network. If the subscriber has permission to use the independent network, information retrieved from the tables is used to determine whether the source subscriber or a destination subscriber has control over the resource.

Abstract: A procedure is described for determining which source to connect to which destination in a non-blocking crossbar switch through which a plurality of sources may be attempting to gain access to a plurality of destinations. To this end, a metric is dynamically associated with each source and with each destination. Matching of sources to destinations is accomplished by iteratively assigning the destination having the smallest metric of all currently unmatched destinations to the source having the smallest metric of all currently unmatched source.

Abstract: In a printed circuit board ejector system, ejector levers are mounted on the outer surface of a faceplate that is constructed to withstand printed circuit board insertion forces without bending or breaking. The faceplate is then fastened to the printed circuit board. Since there is no opening in the faceplate through which the ejector lever passes, electromagnetic radiation cannot leak through the faceplate at this location.

Abstract: A disk drive packaging apparatus has a chassis with open ends that encloses all of the disk drives. The open ends of the chassis are covered with conductive screens. A disk-drive carrier is provided for each drive that holds, but does not enclose, the disk drive. The screens provide both emission containment and guarantees adequate air distribution for cooling. Because the screens are able to contain the radiation emission, conductive enclosures are not needed for each separate drive, with the result that the drives can be packed more densely.

Abstract: An air vent comprises a vent assembly including an electrically-conductive screen mounted inside an enclosure constructed of panels. One or more of the panels has an array of holes through it. The holes are configured and sized to prevent an appendage, such as a finger from penetrating the enclosure. However, the collective hole area is sufficient to permit adequate airflow. The conductive screen covers the holes and provides for EMI suppression.