We propose to develop a FORTRAN-based portable parallel programming system. This system will allow user programs to run unchanged on most MIMD machines with shared as well as non-shared memory. The unique aspects of this system will be (a) message driven execution for latency tolerance, (b) information sharing abstractions, (c) extensive support for reuse and modularity, (d) extensive support for highly irregular computations in the form of dynamic task creation, dynamic load balancing and prioritized scheduling. Message driven execution is a novel technique developed in Charm since 1986, that eliminates some impediments to high performance on massively parallel machines. A visual program development system will also be developed which will simplify the task of specifying asynchronous parallel computations. An accompanying trace driven simulation system will be developed for predicting performance with different architectural parameters. This work will be based on technology developed by University of Illinois which is being licensed by the offerer. Message driven execution is a novel technique to eliminate impediments to high performance in the prevalent SPMD parallel programming model and to obtain increased processing speeds. The developed system will run programs portably on iPSC/860, Paragon, CM-5, NCUBE, networks of workstations, sharfed memory machines, and possibly other new MIMD machines.A portable parallel FORTRAN with message driven execution will overcome performance impediments for massively parallel processing, and along with its support for reuse, and irregular computations, will advance the state of art considerably. As a result, it is expected to have significant commercial applications in computational science and engineering.Parallel Programming, Portability, Message-driven, FORTRAN, irregular