Design and implementation of MPI on Puma portals

As the successor to SUNMOS, the Puma operating system provides a flexible, lightweight, high performance message passing environment for massively parallel computers. Message passing in Puma is accomplished through the use of a new mechanism known as a portal. Puma is currently running on the Intel Paragon and is being developed for the Intel TeraFLOPS machine. We discuss issues regarding the development of the Argonne National Laboratory/Mississippi State University implementation of the Message Passing Interface standard on top of portals. Included is a description of the design and implementation for both MPI point-to-point and collective communications, and MPI-2 one-sided communications.