Scalable libraries in a heterogeneous environment

This paper concerns itself with efforts to extend multicomputer libraries to a hierarchical, heterogeneous network environment. Two classes of support for such libraries are discussed: first, the message-passing features needed to establish groups of communicating processes, and communication contexts within which libraries can safely work. Second, it discusses message-passing primitives that encapsulate heterogeneity, hiding it from the user program (and library alike), and eliminating it when it proves unnecessary (within a homogeneous invocation, for instance). The multicomputer toolbox first-generation scalable libraries, and zipcode message-passing systems are the means by which the author demonstrates his research, so they are discussed. He relates zipcode syntax and semantics to the emerging MPI standard, when appropriate.<>