Reusing sequential software in a distributed environment

In this paper we present and discuss a real experience of reusing sequential software in a parallel and physically distributed computing environment. Specifically, we have combined the functionalities of two existing systems previously developed at our Department. One, Tracs, is a programming environment for networked, heterogeneous machines that, among other things, is able to generate process farms out of a pure sequential code. The other, SPACE, is a graphical tool that generates sequential Fortran programs for simulating digital transmission systems. We have implemented a tool that restructures SPACE-generated programs to let them match the input required by the Tracs process farm generator. The result is that users of SPACE can transparently take advantage of networked and heterogeneous workstations to run their simulations. We have tackled the problems arising from both parallelism and distribution. The techniques we have used can be easily applied to any problem that can be modelled according to the process farm paradigm. Moreover, our experience shows that the Tracs framework may constitute a sound basis for facilitating engineering efforts on the reuse of sequential software in distributed environments.