We present an overview of research at the Center for Research on Parallel Computation designed to provide an efficient, portable programming model for scientific applications possessing both task and data parallelism. Fortran M programs exploit task parallelism by provid ing language extensions for user-defined process man agement and typed communication channels. A com bination of compiler and run-time system support en sures modularity, safety, portability, and efficiency. Fortran D and High Performance Fortran programs ex ploit data parallelism by providing language exten sions for user-defined data decomposition specifica tions, parallel loops, and parallel-array operations.