We present an architecture for distributed, heterogeneous systems where there is a clear separation of the concerns for Computation, Coordination, Configuration respectively, motivated by the different needs when these are considered. The computation part is often implemented in traditional programming code, and packaged as services, the other concerns might need to be created much later and by other people in separate organisations, or even by end users. In this paper we present the model used by the Palcom middleware where each of the concerns can be implemented separate, in separate representations, by separate people and yet combined and updated afterwards. The Palcom middleware is implemented in Java and in active use in research projects and in commercial products.