The viable system architecture

This paper presents the Viable System Architecture as a high-level reference architecture. It is component system architecture motivated by an emerging class of applications we classify as "complex systems." The architecture is based on the Viable System Model: a cybernetic model of organizations. The concept of Viability is introduced as the overall quality desired of software for complex systems. We explain how viability is achieved by the interaction of a number of principles: autonomy and adaptation; recursion and hierarchy; and invariants and self-reference. The special structure of a component in this architecture is described in detail. The nature of an interface is also described. This unique component interface mechanism defines the component framework and provides for dynamic assembly of systems of sub-systems. We present an outline of a business-to-business e-commerce application to illustrate the qualities and principles expected from software systems developed based on the architecture. We are currently building a prototype of this system to verify and validate the architecture.