Integration with the environment.

One of the most important aspects of the usability of an MPI implementation is how well MPI applications are integrated into the environment. Some of the important issues are:

• Is the operating system or some other system software aware of a parallel application as a distinct entity, rather than as a collection of unrelated serial processes?
• Does the implementation provide flexibility in handling standard input and output, such as optional broadcasting of stdin and per-process labeling of stdout. Is standard output available, without excessive buffering, from all processes?
• Is process management robust? Is a terminal interrupt propagated to all processes in an MPI application? Can a parallel application leave unkilled ``orphaned'' processes that must be detected and killed off manually?

In answering these questions, it is often difficult to separate the MPI implementation from the parallel environment. This review tries to keep the focus on MPI itself.