A supercomputer system interconnect and scalable IOS

The evolution of system architectures and system configurations has created the need for a new supercomputer system interconnect. Attributes required of the new interconnect include commonality among system and subsystem types, scalability, low latency, high bandwidth, a high level of resiliency, and flexibility. Cray Research Inc. is developing a new system channel to meet these interconnect requirements in future systems. The channel has a ring-based architecture, but can also function as a point-to-point link. It integrates control and data on a single, physical path while providing low latency and variance for control messages. Extensive features for client isolation, diagnostic capabilities, and fault tolerance have been incorporated into the design. The attributes and features of this channel are discussed along with implementation and protocol specifics.