In an inter-subsystem communication system which has a communication queue enqueued by one subsystem having processors and dequeued by another subsystem having processors, there is provided between the subsystems direct memory access means which permits either of the subsystems to directly access a memory...http://www.google.com.tw/patents/US4272819?utm_source=gb-gplus-share專利 US4272819 - Inter-subsystem direct transfer system
