Software development or engineering software also started to gain acceptance in the late 1980s. These “upper CASE tools” for model processes and functions work on a principle similar to the software used to model processes. There are also data modeling and object- oriented modeling modules, up to the modeling of the entire information systems architecture. See [Schö01], Chapters 3 and 4. A “lower CASE tool” converts the model in the upper CASE tool into an executable program. A typical upper CASE tool is “System Architect,” and one example of an upper and lower CASE tool suitable for large-scale applications is “IEF/IEW.” This type of software falls outside the scope of this chapter.