Commodity high performance computing at commodity prices

The entry price of supercomputing has traditionally been very high. As processing elements, operating systems, and switch technology become cheap commodity parts, building a powerful supercomputer at a fraction of the price of a proprietary system becomes realistic. We have recently purchased, in support of both our local and national collaborations, a dedicated computational cluster of eight DEC Alpha workstations. Each node has a 500MHz AXP21164A processor with 256Mb memory funning Windows NT 4.0 and cost under 6000 pounds. They are connected by 100Mb/s switched ethernet. In this paper we discuss some of the issues raised by our choice of processor, operating system and interconnection network. The results we present indicate that the cluster is fully competitive with systems from major vendors for a wide range of engineering and science applications, and at a cost lower by at least a factor of three. Indeed the only current area of under-performance relative to these vendors' high-end offerings is the inter-node network bandwidth and latency. We give some initial results indicating how the network performance might be improved under Windows NT.