This paper discusses Nimrod, a tool for performing parametised simulations over networks of loosely coupled workstations. Using Nimrod the user interactively generates a parametised experiment. Nimrod then controls the distribution of jobs to machines and the collection of results. A simple graphical user interface which is built for each application allows the user to view the simulation in terms of their problem domain. The current version of Nimrod is implemented above OSF DCE and runs on DEC Alpha and IBM RS6000 workstations (including a 22 node SP2). Two different case studies are discussed as an illustration of the utility of the system. 1 INTRODUCTION A wide range of scientific and engineering experiments can be solved using numeric simulation. Examples include finite element analysis, computational fluid dynamics, electromagnetic and electronic simulation, pollution transport, granular flow and digital logic simulation. Accordingly, some very large codes have been written over ...

Distributed high-performance computing---so-called metacomputing---refers to the coordinated use of a pool of geographically distributed high-performance computers. The user's view of an ideal metacomputer is that of a powerful monolithic virtual machine. The implementor 's view, on the other hand, is that of a variety of interacting services implemented in a scalable and extensible manner. In this paper, we present MOL, the Metacomputer Online environment. In contrast to other metcomputing environments, MOL is not based on specific programming models or tools. It has rather been designed as an open, extensible software system comprising a variety of software modules, each of them specialized in serving one specific task such as resource scheduling, job control, task communication, task migration, user interface, and much more. All of these modules exist and are working. The main challenge in the design of MOL lies in the specification of suitable, generic interfaces for the effective ...

The coordinated use of geographically distributed computers, or metacomputing, can in principle provide more accessible and cost-effective supercomputing than do conventional highperformance systems. However, we lack evidence that metacomputing systems can be made easily usable or that large numbers of applications are able to exploit metacomputing resources. In this article, we present work that addresses both these concerns. The basis for this work is a system called Nimrod that provides a desktop problemsolving environment for parametric experiments. We describe how Nimrod has been extended to support the scheduling of computational resources located in a wide-area environment and report Proceedings of the 20th Australasian Computer Science Conference, Sydney, Australia, February 5--7 1997. on an experiment in which Nimrod was used to schedule a large parametric study across the Australian Internet. The experiment provided both new scientific results and insights into Nimrod capabi...

This paper discusses Nimrod, a tool for performing parametised simulations over networks of loosely coupled workstations. Using Nimrod the user interactively generates a parametised experiment. Nimrod then controls the distribution of jobs to machines and the collection of results. A simple graphical user interface which is built for each application allows the user to view the simulation in terms of their problem domain. The current version of Nimrod is implemented above OSF DCE and runs on DEC Alpha and IBM RS6000 workstations (including a 22 node SP2). Two different case studies are discussed as an illustration of the utility of the system. 1

This work is the result of the guidance, support, and encouragement I have received from my wife, family, advisors and colleagues. I would like to thank Argonne National Laboratory for supporting a majority of my graduate school work and access to their original 128 node IBM SP system that the original EASY scheduler was developed on. As EASY matured and scalability became the focus of my research, the Cornell Theory Center provided a new one-of-a-kind opportunity for me. Their exceptionally well run IBM SP system combined with their excellent working relationship with IBM were the two key factors that made the EASY-LoadLeveler work possible. The freedom to do this research and the time to consider appropriate solutions has been invaluable. I would also like to thank my advisors at the Illinois Institute of Technology especially Dr. Kenevan for helping me formulate this work and the opportunity to do this research under his guidance and Dr. Martha Evens for her patience and encouragement during some difficult times. I would like to thank my parents for instilling in me the importance of “aiming high ” and working hard to achieve my goals. These lessons combined with their love and