Abstract
Progress in Prolog applications requires ever better performance and scalability from Prolog implementation technology. Most modern Prolog systems are emulator-based. Best performance thus requires both good emulator design and good memory performance. Indeed, Prolog applications can often spend hundreds of megabytes of data, but there is little work on understanding and quantifying the interactions between Prolog programs and the memory architecture of modern computers. In a previous study of Prolog systems we have shown through simulation that Prolog applications usually, but not always, have good locality, both for deterministic and non-deterministic applications. We also showed that performance may strongly depend on garbage collection and on database operations. Our analysis left two questions unanswered: how well do our simulated results holds on actual hardware, and how much did our results depend on a specific configuration? In this work we use several simulation parameters and profiling counters to improve understanding of Prolog applications. We believe that our analysis is of interest to any system implementor who wants to understand his or her own system's memory performance. Copyright 2002 ACM.

Abstract
In this paper we introduce MOMEMTO (MOre MEMory Than Others) a new set of kernel mechanisms that allow users to have full control of the distributed shared memory on a cluster of personal computers. In contrast to many existing software DSM systems, MOMEMTO supports efficiently and flexibly global shared-memory allowing applications to address larger memory space than that available in a single node. MOMEMTO has been implemented in the Linux 2.4 kernel and preliminary performance results show that MOMEMTO has low memory management and communication overheads and that it can indeed perform very well for large memory configurations.

Abstract
This paper evaluates the performance of three popular technologies used to interconnect machines on clusters: Fast Ethernet, Myrinet and Giganet. To achieve this purpose, we used the NAS Parallel Benchmarks. Surprisingly, for the LU application, the performance of Fast Ethernet was better than Myrinet. We also evaluate the performance gains provided by VIA, a user lever communication protocol, when compared with TCP/IP, a traditional, stacked-based communication protocol. The impacts caused by the use of Remote DMA Write are also evaluated. The results show that Fast Ethernet, when combined with a high performance communication protocol, such as VIA, has a good cost-benefit ratio, and can be a good choice to connect machines on a small cluster environment where bandwidth is not crucial for applications.

Abstract

Abstract
In this paper we present an implementation of the general system for type inference algorithms HM(X), using Prolog and Constraint Handling Rules. In our implementation the difference between the general aspects of the type inference algorithms and the constraint resolution module becomes clearer, when compared to other implementations of the same systems, usually made in a functional programming language. In the constraint module, solving equality constraints, here implemented by Prolog unification, is completely separated from constraint simplification, which is made by a solver implemented in CHR for each system. CHR rules become a clear and natural way of specifying the simplification mechanism. © 2002 Publishd by Elsevier Science B.V.

Abstract
Logic programming is based on the idea that computation is controlled inference. The Extended Andorra Model provides a very powerful framework that supports both co-routining and parallelism. We present the BEAM, a design that builds upon David H. D.Warren’s original EAM with Implicit Control. The BEAM supports Warren’s original EAM rewrite rules plus eager splitting and sequential conjunctions. We discuss the main issues in the implementation of the BEAM and show that the EAM with Implicit Control can perform quite well when compared with other implementations that use the Andorra principle. © Springer-Verlag Berlin Heidelberg 2001