Architecture and implementation of Vulcan

Abstract

IBM's recently announced Scalable POWERparallel family of systems is based upon the Vulcan architecture, and the currently available 9076 SP1 parallel system utilizes fundamental Vulcan technology. The experimental Vulcan parallel processor is designed to scale to many thousands of microprocessor-based nodes. To support a machine of this size, the nodes and network incorporate a number of unusual features to scale aggregate bandwidth, enhance reliability, diagnose faults, and simplify cabling. The multistage Vulcan network is a unified data and service network driven by a single oscillator. An attempt is made to detect all network errors via cyclic redundancy checking (CRC) and component shadowing. Switching elements contain a dynamically allocated shared buffer for storing blocked packet flits from any input port. This paper describes the key elements of Vulcan's hardware architecture and implementation details of the Vulcan prototype.