DIRECTIONS IN PARALLEL PROGRAMMING : HPF , SHARED VIRTUAL MEMORY AND OBJECT PARALLELISM IN pC + +

Fortran and C++ are the dominant programming languages used in scientific computation. C,onsequently, extensions to these languages are the most popular for programming massively parallel computers. We discuss two such approaches to parallel Fortran and one approach to C++. The High Performance Fortran Forum has designed HPF with the intent of supporting data parallelism on Fortran 90 applications. HPF works by asking the user to help the compiler distribute and align the data structures with the distributed memory modules in the system. Fortran-S takes a different approach in which the data distribution is managed by the operating system and the user provides annotations to indicate parallel control regions. In the case of C++, we look at pC++ which is based on a concurrent aggregate parallel model. *This research is supported by DARPA under contract AF 30602-92-C-0135 from Rome Labs, National Science Foundation Office of Advanced Scientific (:omputing under grant ASC-9111616 and Esprit BRA APPARC and by the National Aeronautics and Space Administration under NASA contract NAS1-19480 while one of the authors was in residence at ICASE, Mail Stop 132(i:, NASA Langley Research Center, Hampton, VA 23681.