This project is building a high-performance multiprocessor from commodity desktop computer systems and off-the-shelf interconnects. Commercial Intel Pentium workstation boards, each with attached memory, disk, and I/O, are attached to a Paragon backplane. Communication uses a new mechanism called virtual memory-mapped communication, which disguises interprocessor communication as write operations to memory. The node interface maps physical pages in the memories of individual nodes to each other, so that a write to one mapped page results in messages to other nodes that share the mapped page. The operating systems on the individual nodes use their ordinary virtual memory mechanism to support virtual page mapping. In addition to this word-by-word communication, DMA transfers are available, with control registers located in the address space of individual processes. This allows high bandwidth communication that maintains user-level protection. Research to be addressed in the project includes the achievement of high-bandwith low-latency communication between processes, the structure of an I/O system supported by the new communication mechanism, and performance evaluation of the resulting system.
