MPI

Message passing paradigm widely used on parallel machines, and well understood, but each vendor has their own variant.
Lack of a standard has significantly impeded the development of portable software and libraries for message-passing machines.
MPI defines a set of routines which are useful to a wide range of users and efficiently implementable on a wide range of computers.
Intended to become a widely used standard, gradually replacing the vendor- specific and other interfaces used by C and Fortran programs today.
MPIF is not sanctioned or supported by any official standards organization, but virtually all of the major vendors have participated.

Slide 39 of SIAM Tutorial, Jack Dongarra UT/ORNL. (Updated 01/31/95)