Abstract
This work investigates the impact of hybrid coherence protocols on non-scientific applications. We use execution-driven simulation of a scalable multiprocessor and compare the results obtained with a hybrid protocol with a well-known invalidate protocol and an update-based protocol. Our results show that for our sample programs a hybrid protocol with high threshold outperforms both the invalidate-based and update-based protocols, regardless of the type of parallelism exhibited by the benchmarks. We conclude that our applications can benefit from a hybrid protocol, and that multiprocessors designed for running these systems efficiently should adopt some form of hybrid protocol.

Abstract
We describe a programming language for distributed computations that supports mobile resources and is based on a process calculus. The syntax, semantics and implementation of the language are presented with a focus on the novel model of computation.

Abstract
Mobile agents are the latest software technology to program flexible and efficient distributed applications. Most current systems implement semantics that are hard if not impossible to prove correct. In this paper we present MOB, a scripting language for Internet agents encoded on top of a process calculus and with provably sound semantics.

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This paper discusses the design of YapDss, an or-parallel Prolog system for distributed memory parallel machines, such as the Beowulf PC clusters. The system builds on the work of YapOr, an or-parallel system for shared memory machines, and uses the distributed stack splitting binding model to represent computation state and work sharing among the computational workers. A new variant scheme of stack splitting, the diagonal splitting, is proposed and implemented. This scheme includes efficient algorithms to balance work load among computing workers, to determine the bottommost common node between two workers, and to calculate exactly the work load of one worker. An initial evaluation of the system shows that it is able to achieve very good speedups on a Beowulf PC cluster.

Abstract