The rise in network and processing capacity of commodity platforms has made Networks of Workstations an affordable alternative to dedicated parallel computers. However, standard layered communication protocols (e.g., TCP/IP) on commodity operating systems were not designed for high-performance cluster computing. They introduce bottlenecks due to interrupt overhead, memory copying, protocol processing, and latency from inefficient bus and I/O usage. This book identifies these bottlenecks and presents a user-level communication system over Gigabit Ethernet that bypasses the OS entirely. The...