Abstract

Abstract
Recently, new parallel architectures, namely distributed shared memory architectures, have been proposed and built. These combine the ease-of-use of shared memory architectures with the scalability of the message-passing architectures. These architectures provide software and hardware support for shared virtual address space on physically distributed memory. This paper describes Dorpp, an execution model that supports or-parallelism for these machine architectures, namely for the EDS parallel machine. Dorpp uses a shared memory model for or-parallelism. It attempts, however, at exploiting locality and at reducing communication overheads through scheduling and by caching accesses to remote shared data. The problem of memory coherency of cached data is discussed and solutions are proposed. Preliminary evaluation results of the execution model through simulation are presented. © Springer-Verlag Berlin Heidelberg 1993.

Abstract

Abstract

Abstract

Abstract
We argue that in order to exploit both Independent And-and Or-parallelism in Prolog programs there is advantage in recomputing some of the independent goals, as opposed to all their solutions being reused. We present an abstract model, called the Composition-tree, for representing and-or parallelism in Prolog programs. The Composition-tree closely mirrors sequential Prolog execution by recomputing some independent goals rather than fully re-using them. We also outline two environment representation techniques for And-Or parallel execution of full Prolog based on the Composition-tree model abstraction. We argue that these techniques have advantages over earlier proposals for exploiting and-or parallelism in Prolog. © 1993 Ohmsha, Ltd. and Springer.