Over the last twenty years, the open source community has provided more and more software on which the world's High Performance Computing (HPC) systems depend for performance and productivity. The community has invested millions of dollars and years of effort to build key components. But although the investments in these separate software elements have been tremendously valuable, a great deal of productivity has also been lost because of the lack of planning, coordination, and key integration of technologies necessary to make them work together smoothly and efficiently, both within individual PetaScale systems and between different systems. It seems clear that this completely uncoordinated development model will not provide the software needed to support the unprecedented parallelism required for peta/exascale computation on millions of cores, or the flexibility required to exploit new hardware models and features, such as transactional memory, speculative execution, and GPUs. This report describes the work of the community to prepare for the challenges of exascale computing, ultimately combing their efforts in a coordinated International Exascale Software Project.

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We present Monte Carlo results for the force between static quarks, calculated on a large ( 1 6 3~3 2 ) lattice. A simulation with high statistics allows us to compute expectation values for loop factors of size up to 8 X 8 at several values of / 3 in the transition region. Values and errors are tabulated; a fitting procedure is then used to evaluate the force between static quarks and, in particular, its asymptotic limit, i.e., the string tension a. We find good agreement with scaling for > 6, with a ratio between scale parameter A and flu approximately equal to 9.6X lop3.

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