In Uniform Memory Access (UMA) systems, all memory accesses take the same amount of time.Specific examples of UMA machines include Sun's Ultra Enterprise, IBM's iSeries and pSeries servers, the Hewlett-Packard 900, and DEC's AlphaServer.Multistage networks run into wiring constraints and significant latency if the number of processors becomes very large.Thus, the scalability of UMA machines is limited by the properties of interconnection networks.Symmetric multiprocessors are well-known UMA architectures.