TITLE: and MIMD/SIMD Architectures Parallel computing applications differ widely in the type of computational paradigm that is best suited to efficiently exploit their parallelism. Current software systems for parallel hardware support only single-paradigm computing. The objective of this research project is to investigate system-level support for efficient multiparadigm parallel computation. Previous work on coordination languages and multiparadigm sequential programming languages form a solid foundation for this research, although significant new ideas are required. Although current high-performance computer architectures are moving toward a combined MIMD/SIMD organization, very little software and system support exists for such hybrid computer architectures. This research will thus also focus on aspects of multiparadigm computing for massively parallel SIMD and MIMD/SIMD machines, including the Rewrite-Rule Machine as a testbed architecture. The research results will enable future systems designers to better appreciate the engineering trade-offs to efficiently support multiparadigm computing in a parallel environment. The results of this research are expected to enhance the future programming ease of high-performance massively parallel computing systems.