Adventures with portability

Abstract

In this paper we describe the issues we are facing, and some of the solutions we have developed, in porting a complex multi-component simulation model of pastoral dairy-farming scenarios for execution on a high-performance Linux cluster. This exercise is part of a wider goal to develop and implement global optimization procedures for this model which necessarily require very large numbers of simulations to be executed. The structure of the model poses some particularly interesting challenges as it consists of a strongly object-oriented VisualWorks Smalltalk framework which instantiates third-party "component sub-models", written in a variety of standard (e.g. Fortran, C) and proprietary (e.g. ACSL, ObjectPascal) languages, to represent the functionality of the real-world farm sub-systems. Furthermore, it was unfortunately originally constrained to being implemented in a Microsoft Windows environment and made heavy use of the Microsoft COM/DCOM protocol for communication between objects. Although still in the early stages of on-going work, the techniques developed and lessons learned should be relevant to aspects of other situations where there is a requirement to run "legacy applications" on high-performance clusters.