Runtime Support for Virtual BSP Computer

. Several computing environments including wide area networks and nondedicated networks of workstations are characterized by frequent unavailability of the participating machines. Parallel computations, with interdependencies among their component processes, can not make progress if some of the participating machines become unavailable during the computation. As a result, to deliver acceptable performance, the set of participating processors must be dynamically adjusted following the changes in computing environment. In this paper, we discuss the design of a run time system to support a Virtual BSP Computer that allows BSP programmers to treat a network of transient processors as a dedicated network. The Virtual BSP Computer enables parallel applications to remove computations from processors that become unavailable and thereby adapt to the changing computing environment. The run time system, which we refer to as adaptive replication system (ARS), uses replication of data and computati..