Parallel Virtual Machine (PVM) is a widely-used software system that allows a heterogeneous set of parallel and serial UNIX-based computers to be programmed as a single distributed-memory parallel machine. In this paper, an extension to PVM to support dynamic process migration is presented. Support for migration is important in general-purpose workstation environments since it allows parallel computations to co-exist with other applications, using idle-cycles as they become available and off-loading from workstations when they are no longer free. A description and evaluation of the design and implementation of the prototype Migratable PVM system is presented together with some performance results. 1 Introduction PVM [1, 2, 3] is a software system that allows a heterogeneous network of parallel and serial computers to be programmed as a single computational resource. This resource appears to the application programmer as a potentially large distributed-memory virtual computer. Such a s...

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 ...

We are currently involved in research to enable PVM to take advantage of shared networks of workstations (NOWs) more effectively. In such a computing environment, it is important to utilize workstations unobtrusively and recover from machine failures. Towards this goal, we have enhanced PVM with transparent task migration, checkpointing, and global scheduling. These enhancements are part of the MIST project which takes an open systems approach in developing a cohesive, distributed parallel computing environment. This open systems approach promotes plug-and-play integration of independently developed modules, such as Condor, DQS, AVS, Prospero, XPVM, PIOUS, Ptools, etc. Transparent task migration, in conjunction with a global scheduler, facilitates the use of shared NOWs by allowing parallel jobs to unobtrusively utilize nodes that are currently unused. PVM tasks can be moved onto nodes that are otherwise idle, and moved off when the node is no longer free. Experiments show that migrati...

. Scientists are increasingly turning to numerical simulation in order to investigate and model complex environmental systems. Numerical simulation has enormous advantages over laboratory or field experimentation because it has the potential to allow a much greater parameter space to be considered. Numerical simulation is being used for simulating the formation of photochemical air pollution (smog) in industrialised cities. However, computational hardware demands can be great. In this paper we discuss the computational resources that are required in order to achieve a realistic number of results in a timely manner. We describe the parallelisation and distribution of programs that have been used as part of an air pollution study being conducted in Melbourne, Australia. We also describe some computer tools which proved effective in managing this study. Keywords: Application of Parallel Systems, Scientific Computing, Design of Parallel Programs, Shared, Clustered and distributed machines....

Abstract: This paper presents an algorithm for scheduling parallel applications in large-scale, multiuser, heterogeneous distributed systems. The approach is primarily targeted at systems that harvest idle cycles in general-purpose workstation networks, but is also applicable to clustered computer systems and massively parallel processors. The algorithm handles unequal processor capacities, multiple architecture types and dynamic variations in the number of processes and available processors. Scheduling decisions are driven by the desire to minimize turnaround time while maintaining fairness among competing applications. For efficiency, the virtual processors (VPs) of each application are gang scheduled on some subset of the available physical processors.

: This paper concerns the use of distributed computers for solving large scientific modelling problems. In many fields, a designer may wish to explore a set of alternative scenarios. If numerical simulation is used as the experimental process, then this means executing a number of independent jobs and then aggregating the results in some way. There are currently two main ways of organising the execution on multiple computers, namely the use of remote job execution systems, or building distributed applications. This paper explores both of these, and proposes a user interface based on a laboratory bench metaphor. It then describes a prototype system with the advantages of both current job generation methods. The system is built on top of the Distributed Computing Environment from the Open Software Foundation. A real world example, photo chemical pollution modelling, is used as a sample application. 1994 Parallel Computing and Transputers Conference, Wollongong, Nov 94, pp 17 27. 1. INTRO...

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