MPI has proven effective for parallel applications in situations with neither QoS nor fault handling. Emerging environments motivate fault-tolerant MPI middleware. Environments include space-based, wide-area/web/meta computing and scalable clusters. MPI/FT, the system described in the paper, trades off sufficient MPI fault coverage against acceptable parallel performance, based on mission requirements and constraints. MPI codes are evolved to use MPI/FT features. Non-portable code for event handlers and recovery management is isolated. User-coordinated recovery, checkpointing, transparency and event handling, as well as evolvability of legacy MPI codes form key design criteria. Parallel self-checking threads address four levels of MPI implementation robustness, three of which are portable to any multithreaded MPI. A taxonomy of application types provides six initial fault-relevant models; user-transparent parallel nMR computation is thereby considered. Key concepts from MPI/RT-real-time MPI-are also incorporated into MPI/FT, with further overt support for MPI/RT and MPI/FT in applications possible in future.

The equations for mass, momentum, temperature and salinity are formulated in a non-inertial general curvilinear coordinate system to be solved numerically. A flux-difference split type of numerical flux formulation is used for the convective fluxes and the equations are numerically solved in a strongly coupled manner using the discretized Newton-relaxation scheme. The addition of artificial viscosity is not required for stability. Test cases were considered that included laminar flow over a flat plate with prescribed wall temperature and salinity as well as laminar flow with heat transfer over a backward facing step. These computations compare well with existing results. The present numerical scheme was also applied to a body-fitted grid that approximates the entire Atlantic Ocean and rotates with the Earth. These results, though encouraging, must be considered preliminary.>