systems, policies and organizational structures to optimize the processes of an organization. Modeling the business Within the area of enterprise engineering formal methodologies, methods and techniques are designed, tested and extensively used in order to offer organizations reusable business process solutions: Computer-integrated manufacturing open systems architecture (CIMOSA) methodology Integrated definition (IDEF) methodology Petri Nets Unified modeling language (UML) or unified enterprise modeling language (UEML) Enterprise Function Diagrams (EFD) These methodologies/techniques and methods are all more or less suited in modeling the enterprise and its underlying processes. So, which of them are suited for the further development of information technology systems that are needed for effective and efficient (re)designed processes? More important, why using a time-consuming enterprise methodology when information and software engineers can’t or won’t use the unclear results in the development of efficiency enabling IT systems? Before we can give the answers to these questions some short descriptions of the listed methods above are given. Computer-integrated manufacturing open systems architecture CIMOSA provides templates and interconnected modeling constructs to encode business, people and IT aspects of enterprise requirements. This is done from multiple perspectives: information view, function view, resource view, and organization view. These constructs can further be used to structure and facilitate the design and implementation of detailed IT systems. The division in different views makes it a clarifying reference for enterprise and software engineers. It shows information needs for different enterprise functionalities (activities, processes, operations) and corresponding resources. In this way, it can easily be determined which IT-system will fulfill the information needs in a certain activity and process. Integrated definition (IDEF) IDEF is a structured modeling technique, which was first developed for the modeling of manufacturing systems. It was already being used by the U.S. Airforce in 1981. Initially, it had 4 different notations to model an enterprise from a certain viewpoint. These were IDEF0, IDEF1, IDEF2 and IDEF3 for functional, data, dynamic and process analysis respectively. In the past decades, several tools and techniques for the integration of the notations are developed incrementally. IDEF clearly shows how a business process flows through a variety of decomposed business functions with corresponding information inputs, outputs, and actors. Like CIMOSA, it also uses different enterprise views. Moreover, IDEF can be easily transformed into UML-diagrams for the further development of its systems. these positive characteristics make it a powerful method for the development of functional software architectures. Petri Nets Petri