ABSTRACT
Ever since parallel computers hit the HPC market, there was an intense discussion about what should be an appropriate programming model for them. The use of explicit message passing (MP), i.e., communication between processes, is surely the most tedious and complicated but also the most flexible parallelization method. Parallel computer vendors recognized the wish for efficient message-passing facilities, and provided proprietary, i.e., nonportable libraries up until the early 1990s. At that point in time it was clear that a joint standardization effort was required to enable scientific users to write parallel programs that were easily portable between platforms. The result of this effort was MPI, the Message Passing Interface. Today, the MPI standard is supported by several free and commercial implementations [W125, W126, W127], and has been extended several times. It contains not only communication routines, but also facilities for efficient parallel I/O (if supported by the underlying hardware). An MPI library is regarded as a necessary ingredient in any HPC system installation, and numerous types of interconnect are supported.
