Special features of different systems


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MPI makes it relatively easy to write portable parallel programs. However, one thing that MPI does not standardize is the environment within which the parallel program is running. There are three basic types of parallel environments: parallel computers, clusters of workstations, and integrated distributed environments, which we will call ``computational grids,'' that include parallel computers and workstations and that may span multiple sites. Naturally, a parallel computer (usually) provides an integrated, relatively easy way of running parallel programs. Clusters of workstations and grid environments, on the other hand, usually have no standard way of running a parallel program and will require some additional setup. The mpich implementation is designed to hide these differences behind the mpirun script; however, if you need special features or options or if you are having problems running your programs, you will need to understand the differences between these systems. In the following, we describe the special features that apply for workstation clusters, grids (as supported by the globus2 device), and certain parallel computers.

When coupling multiple multicomputers, the globus2 device, described in Section Computational Grids: the globus2 device , may be a better choice than the ch_p4 device.



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