Abstract: An electronic switching and data transmission system for interconnecting a plurality of buses. A switching network interconnects several multi-drop buses using adapters to connect the buses to the switching network. The adapters implements hardware functions to appear to software as if all devices on the several buses were attached to a single large bus. The system permits higher speed transfer modes by eliminating multi-drop bus limitations.

Abstract: A modularly expandable switch-based planar apparatus for insertable multiple bus-based processor cards and/or expansion cards and interconnecting the cards via a multi-stage switch network which resides on the planar apparatus. The cards require no modification or change of any kind, since the connection to the planar apparatus is made as if the planar apparatus contained the standard MicroChannel interconnection. The planar apparatus implements bus converter units to convert the standard bus interface provided by the cards to the switch network interface, so that functions provided by the cards can communicate in parallel over the switch network.

Abstract: A broadcast/switching apparatus makes input port to output port connections on a requested basis quickly and dynamically in a standard mode from any one of the input ports to any one of the output ports, in a multi-cast mode from any one of the input ports to a fixed number of subsets of multiple output ports simultaneously, or in a broadcast mode from any one of the input ports to all output ports simultaneously, using a new asynchronous approach to resolve either broadcast or multi-cast contention among input ports. The normal mode of the broadcast/switch apparatus requires absolutely no synchronization among any of the input and output ports which interface to the apparatus. The broadcast/switch apparatus also incorporates a new accept protocol that enables a positive feedback indication to be returned to the sender of a multi-cast or broadcast operation to inform it that the multi-cast or broadcast transmission was correctly received by all elements involved in the multi-cast or broadcast.

Abstract: Disclosed is multi-media switching apparatus for performing digital, analog, and/or optical communications amongst multiple nodes over switching networks. The key aspect of the present invention is the full parallel aspect of the switching apparatus which supports n simultaneously, low-latency connections, where n is the number of functional elements interconnected by the switching network. Any of the n simultaneous transmissions can be digital, analog, or optical in any proportion. In addition, the present invention can also serve as a high-speed distributed controller for the purpose of of selecting analog or optical switches for information transfer between elements of the system.

Abstract: At least-recently used (LRU) storage means and its associated logic maintain usage history for associativity class entries of a cache directory. The storage means includes an independent storage array for each of the bit positions of an LRU binary code pattern. Parity bits are provided in the arrays for each LRU bit. Separate read/write controls simultaneously write updated LRU bits to some of the arrays and read out unchanged LRU bits from the remaining arrays during updating of a usage history entry when its associativity class is used. Pattern checking logic collects the update bits and the unchanged bits during the update cycle to determine whether or not the new entry is a valid LRU combination. A parity bit is written with each of the update LRU bits written into the arrays and parity bits are read out from the arrays with the unchanged LRU bits for parity checking of each unchanged LRU bit during updating of usage history entries.