OR-parallel evaluation of logic programs on a multi-ring dataflow machine

Logic programming languages have gained wide acceptance because of two reasons. First is their clear declarative semantics and the second is the wide scope for parallelism they provide which can be exploited by building suitable parallel architectures. In this paper, we propose a multi-ring dataflow machine to support theOR-parallelism and theArgument parallelism of logic programs. A new scheme is suggested for handling the deferred read mechanism of the dataflow architecture. The required data structures, the dataflow actors and the builtin dataflow procedures for OR-parallel execution are discussed. Multiple binding environments arising in the OR-parallel execution are handled by a new scheme called thetagged variable scheme. Schemes for constrained OR-parallel execution are also discussed.