Java's support for parallel and distributed processing makes the language attractive for metacomputing applications, such as parallel applications that run on geographically distributed (wide-area) systems. To obtain actual experience with a Java-centric approach to metacomputing, we have built and used a high-performance widearea Java system, called Manta. Manta implements the Java RMI model using different communication protocols (active messages and TCP/IP) for different networks. The paper shows how widearea parallel applications can be expressed and optimized using Java RMI. Also, it presents performance results of several applications on a wide-area system consisting of four Myrinet-based clusters connected by ATM WANs. 1 Introduction Metacomputing is an interesting research area that tries to integrate geographically distributed computing resources into a single powerful system. Many applications can benefit from such an integration [11, 22]. Metacomputing systems support such...

The Legion system defines a software architecture designed to support metacomputing, the use of large collections of heterogeneous computing resources distributed across local- and wide-area networks as a single, seamless virtual machine. Metasystems software must be extensible because no single system can meet all of the diverse, often conflicting, requirements of the entire present and future user community, nor can a system constructed today take best advantage of unanticipated future hardware advances. Metasystems software must also support complete site autonomy, as resource owners will not turn control of their resources (hosts, databases, devices, etc.) over to a dictatorial system. Legion is a metasystem designed to meet the challenges of managing and exploiting wide-area systems. The Legion virtual machine provides secure shared object and shared name spaces, application adjustable fault-tolerance, improved response time, and greater throughput. Legion tackles problems not sol...

Many of the systems that currently allow computing on the web target specific tools. Such solutions tend to be non-reusable in spite of the fact that they involve a significant amount of duplicated effort. This paper describes the issues involved in the design of a demandbased network-computing system, and presents an operational prototype (the Purdue University NetworkComputing Hubs, or PUNCH) that allows users to access and run existing software tools via standard worldwide web browsers. The tools do not have to be written in any particular language, and access to sourcecode is not required. The PUNCH infrastructure can be distributed in a manner that allows tools to be (usertransparently) executed wherever they reside. Currently, PUNCH contains over thirty tools from eight universities and four vendors, and serves more than 500 users. During the past three years, PUNCH users have logged more than 860,000 hits and have performed over 54,000 simulations. 1. Introduction There is inc...

Java’s support for parallel and distributed processing makes the language attractive for metacomputing applications, such as parallel applications that run on geographically distributed (wide-area) systems. To obtain actual experience with a Java-centric approach to metacomputing, we have built and used a high-performance wide-area Java system, called Manta. Manta implements the Java Remote Method Invocation (RMI) model using different communication protocols (active messages and TCP/IP) for different networks. The paper shows how widearea parallel applications can be expressed and optimized using Java RMI. Also, it presents performance results of several applications on a wide-area system consisting of four Myrinetbased clusters connected by ATM WANs. We finally discuss alternative programming models, namely object replication, JavaSpaces, and MPI for Java.

The main advantage of a metacomputer is not its peak performance but better utilization of its machines. Therefore, e#cient scheduling strategies are vitally important to any metacomputing project. A real metacomputer management system will not gain exclusive access to all its resources, because participating centers will not be willing to give up autonomy. As a consequence, the scheduling algorithm has to deal with a set of local sub-schedulers performing individual machine management. Based on the proposal made by Feitelson and Rudolph in 1998 we developeda scheduling model that takes these circumstances into account. It has been implemented as a generic simulation environment, which we make available to the public. Using this tool, we examined the behavior of several well known scheduling algorithms in a metacomputing scenario. The results demonstrate that interaction with the sub-schedulers, communication of parallel applications, and the huge size of the metacomputer are among th...

ing with credit is permitted. To copy otherwise, to republish, to post on servers, to redistribute to lists, or to use any component of this work in other works, requires prior specific permission and/or a fee. Permissions may be requested from Publications Dept, ACM Inc., 1515 Broadway, New York, NY 10036 USA fax +1 (212) 869-0481, or permissions@acm.org. The Purdue University Network-Computing Hubs: Running Unmodified Simulation Tools via the WWW Nirav H. Kapadia Jos'e A. B. Fortes and Mark S. Lundstrom School of Electrical and Computer Engineering, Purdue University Association for Computing Machinery, Inc., 1515 Broadway, New York, NY 10036, USA Tel: (212) 555-1212; Fax: (212) 555-2000 This paper describes the Web interface management infrastructure of a functional networkcomputingsystem (PUNCH) that allows users to run unmodified simulation packages at geographically dispersed sites. The system currently contains more than forty university and commercial simulation to...

this paper we describe the architecture of a software system for access and management of geographically distributed HPC systems. There are three key components: 1. The Computing Center Software (CCS) is a resource management software for the access and system administration of HPC systems that are operated in a single site. It gives a vendor-independent interface to parallel systems and it provides tools for specifying, configuring and scheduling system components.

Grid computing systems are being positioned as a computing infrastructure of the future that will enable the usage of wide-area network computing systems for a variety of challenging applications. The architecture of the Grid will determine if it will meet these challenges. We propose a Grid architecture that is motivated by the largescale routing principles in the Internet to provide an extensible, high-performance, scalable, and secure Grid. Central to the proposed architecture is a middleware called the Grid operating system (GridOS). This paper describes the components of the GridOS. The GridOS includes several novel ideas including (i) a flexible naming scheme called the "Gridspaces," (ii) a service mobility protocol, and (iii) a highly decentralized Grid scheduling mechanism called the router-allocator. 1.

. Several performance analysis tools have been developed with the drawback of dedicated hardware solutions or the compute intenseness of simulations. The modern microprocessors, with hardware support for counting of system hardware events, now make possible universal software tools for the performance analysis of complex application programs such as the SPEC benchmarks. In this paper, we present a new method to determine system resource utilization #cache miss ratios, CPI values, branch miss predictions# of arbitrary programs, based on a sampling technique, combined with access to processor-internal event counter registers. We present the sprof tool set that is based on this method and enables also the detailed analysis of individual subroutines of a program, as they are executed over time. The high accuracy and the negligible overhead of the tool set is demonstrated. We used the SPEC95 benchmark suite, consisting of 8 integer and 10 #oating-pointintensive non-trivial pro...

We present a new parallel programming tool environment that is (1) accessible and executable "anytime, anywhere," through standard Web browsers and (2) integrated in that it provides tools that adhere to a common underlying methodology for parallel programming and performance tuning. The environment is based on a new network computing infrastructure, developed at Purdue University.