Modeling Information Systems as Systems of Systems

Large industrial information systems are composed of dozens of inter-operating software applications. Each of them implements a relatively independent set of functions but also participates to business processes involving more applications. Applications may be COTS acquired from different vendors or custom-developed. The network of them evolves and grows in time. Many development groups/vendors manage the network. All these characteristics support the idea that large information systems may be interpreted as Systems of Systems (SoS) and that this view may provide value to IT managers. In the paper, we present an experience report of SoS concepts application to the information system of a large retail company. In this System of Systems, a critical problem is the absence of documents providing SoS views of the whole information system: the set of applications, their relationships and the impact of business processes on the network of applications. To mitigate the problem, we developed a set of models using the minimalist approach (the selection of the minimal set of documents based on a cost/benefit analysis) and the ArchiMate modeling standard and tools. A static view (software applications and relations) and dynamic views (business processes and their interaction with software applications) model each business area. We discuss the current use and benefits of the models and the forecast improvements.