Supercomputing is a moving target. Irving Wladawsky-Berger has given a nice summary of how supercomputers are scaling (we are beginning to see petaflop machines) and what the challenges for the scale up to exascale computing will be and the significant changes to predictive modeling that they will enable.<p>In case you have not noticed, supercomputing (at least at the teraflop level) has become mainstream. We are beginning to see monolithic supercomputers, that is, machines primarily dedicated to a particular application or sub-application, in a variety of production situations. Often these monolithic supercomputers are constructed of standard commodity servers; some use hardware accelerators to substantially improve throughput or real time performance by exploiting unrealized parallelism. Specialization by an accelerator can improve throughput by significant factors, often an order of magnitude or two.