A class library approach to concurrent object-oriented programming with applications to VLSI CAD

Despite increasing availability, the use of parallel platforms in the solution of significant computing problems remains largely restricted to a set of well-structured, numeric applications. This is due in part to the difficulty of parallel application development, which is itself largely the result of a lack of high-level development environments applicable to the majority of extant parallel architectures. This thesis addresses the issue of facilitating the application of parallel platforms to unstructured problems through the use of object-oriented design techniques and the actor model of concurrent computation. We present a multilevel approach to expressing parallelism for unstructured applications: a high-level interface based on the actor and aggregate models of concurrent object-oriented programming, and a low-level interface which provides an object-oriented interface to system services across a wide range of diverse parallel architectures. The interfaces are manifested in the ProperCAD II library, a C++ object library supporting actor concurrency on microprocessor-based parallel architectures and appropriate for applications exhibiting medium-grain parallelism. The interface supports uniprocessors, shared memory multiprocessors, distributed memory multicomputers, and hybrid architectures comprising network-connected clusters of uni- and multiprocessors. The library currently supports workstations from Sun, shared memory multiprocessors from Sun and Encore, distributed memory multicomputers from Intel and Thinking Machines, and hybrid architectures comprising IP network-connected clusters of Sun uni- and multiprocessors. We demonstrate our approach through an examination of the parallelization process for two existing unstructured serial applications drawn from the field of VLSI computer-aided design. We compare and contrast the library-based actor approach to other methods for expressing parallelism in C++.