An improved signaling protocol for use in a multiprocessor system enables concurrent access to a common system bus during an I/O bus access. This reduces the system bus idling time without introducing complexities into the system bus architecture which might otherwise reduce the overall bus bandwidth...http://www.google.ca/patents/US5426740?utm_source=gb-gplus-sharePatent US5426740 - Signaling protocol for concurrent bus access in a multiprocessor system
