QCDOC: Project status and first results

After a brief overview of quantum chromodynamics (QCD), the fundamental theory of the strong interactions, we describe the QCDOC computer, its architecture, construction, software and performance. Three 12K-node, 4 Teraflops (sustained) QCDOC computers have been constructed, two at the Brookhaven National Lab and one at the University of Edinburgh. The present status of these machines and their first physics results and objectives are discussed and the catalytic role of the SciDAC program in enabling the effective use of this new architecture by the US lattice QCD community outlined. © 2005 IOP Publishing Ltd.