A communications subsystem for the homogeneous multiprocessor

The homogeneous multiprocessor (HM) has a linear-array topology, with interprocess communications achieved through a high-speed parallel bus, as well as by the sharing of memory between nearest neighbors. The communications subsystem uses the available resources (shared memory, fast network, interprocessor signaling) to provide an efficient and orderly data-transfer facility among the component processors. A programming environment very similar to STREAMS provides a general framework that allows easy construction of the various protocols needed within the HM, as well as low-cost user access to the novel architectural features of the HM. The IEEE 802.2 protocol is used to unify the various special communications paths. The use of STREAMS permits casting distributed algorithms (for the control of shared regions and (simulated) global memory) as protocols. The use of the programming language Turing Plus has considerably shortened the development time. An implementation of the framework and the link-level protocol has been completed