In most of today's agent systems migration of agents requires homogeneity in the programming language and/or agent platform in which an agent has been designed. In this paper an approach is presented with which heterogeneity is possible: agents can migrate between non-identical platforms, and need not be written in the same language. Instead of migrating the "code" (including data and state) of an agent, a blueprint of an agent's functionality is transferred. An agent factory generates new code on the basis of this blueprint. This approach of generative mobility not only has implications for interoperability but also for security, as discussed in this paper.

The combined computing capacity of the workstations that are present in many organisations nowadays is often under-utilised, as the performance for parallel programs is unpredictable. Load balancing through dynamic task re-allocation can help to obtain a more reliable performance. The Esprit project Dynamite provides such an automated load balancing system. It can migrate tasks that are part of a parallel program using a message passing library. Currently Dynamite supports PVM only, but it is being extended to support MPI as well. The Dy- namite package is completely transparent, i.e. neither system (kernel) nor application source code need to be modified. Dynamite supports migration of tasks using dynamically linked libraries, open files and both direct and indirect PVM communication. Monitors and a scheduler are included. In this paper, we first briefly describe the Dynamite system.

Optimistic parallel discrete event simulation method is applied to large scale data parallel applications. Specificly, optimizations for state saving of large state vectors and bounded optimism are incorporated in the simulation environment. Dynamic load balancing is studied, and a checkpoint and migration mechanism is implemented and integrated with the PVM message passing environment.

Abstract. In this paper a methodology is presented that has been developed in the CAMAS ’ project for the purpose of decomposition and mapping of parallel pro-cesses to processor topologies. The methodology has been implemented in terms of a toolset. thus allowing automatic decomposition and mapping of parallel pro-cesses. The parallel processes and processors are modelled according to a gener-ally applicable formalism. based on the so-called virtual particle model. As a case study the presented methodology is applied to parallel linite element simulations. Keyords: (redrtndanr) domain decomposition. mapping, virtual particles, parallel process mod-. lling

With the advent of high speed networks, distributed cluster computing and metacomputing have assumed an enormous interest. However, software methods and techniques to make the full potential of these distributed environments available, are not yet mature. In this paper, we focus on dynamic load balancing of resources and applications as one of the crucial techniques to optimize performance in distributed environments. Some design and implementation details are described, and early experimental results are presented.

This paper is structured as follows. Section 2 introduces application and machine representations that are used to model the performance characteristics of parallel static applications on parallel machines. Section 3 gives a detailed study on the structure of the phase space (or landscape) of the TAP. Section 4 is dedicated to the geometrical phase transition occurring in the TAP. In section 5 the following experimental methods are presented: Simulated Annealing (SA) [8], for finding optima, and Weinberger correlation for phase space structure characterisation [21]. In section 6 experimental results are presented, which are discussed in section 7. Finally, some concluding remarks and directions for future work are given in section 8. 2 Application and Machine Models

. Workstations make up a very large fraction of the total available computing capacity in many organisations. In order to use this capacity optimally, dynamic allocation of computing resources is needed. The Esprit project Dynamite addresses this load balancing problem through the migration of tasks in a dynamically linked parallel program. An important goal of the project is to accomplish this in a manner that is transparent both to the application programmer and to the user. As a test bed, the Pam-Crash software from ESI is used. Introduction Workstations have become ubiquitous in many organisations. By their nature, they are often used intensively during normal working hours, and are often largely idle otherwise. They represent a huge reservoir of computing capacity that can be used much more efficiently. Thus, we currently witness a shift of emphasis in high-performance computing from expensive, special-purpose monolithic systems to the use of clusters of workstations or ...

Ecient load balancing is essential for the development of parallel distributed computing. Many parallel computing environments use TCP or UDP through the socket interface as a communication mechanism. This paper presents design and development of a prototype implementation of a network interface which may keep communication between processes during process migration. This new communication library is a substitution of the well-known socket interface. It is implemented in the userspace; it is portable, and no modication of user applications are required. The TCP/IP is applied for internal communication what guarantees relatively high performance and portability. Keywords: distributed computing, load balancing, process migration, Dynamite, sockets. 1 Introduction In order to use distributed computing power eciently it is essential to enable process migration from one, heavily loaded host to another, idle host, in a way that also allows the original host to be serviced (i...

The total computing capacity of workstations can be harnessed more efficiently by using a dynamic task allocation system. The Esprit project Dynamite provides such an automated load balancing system, through the migration of tasks of a parallel program using PVM.

In this article we present a first time evaluation of a metamorphosic compute resource (MCR) in a real world scenario. During day-time the MCR compute nodes are ordinary office computers, used in a student lab. Thanks to our enhancements, the computers become part of an OpenMosix based compute resource during the night. The single most common reason for partial loss of computing power was students and/or personnel switching off some of the machines in the evening by mistake: something easily solved by e.g. implementing `wake on LAN'. We also found that less than 1 per mill of all disturbances was non-trivial in nature which clearly indicates the strength of the architecture.