Degrees of consciousness for reuse of software in practice: Maintainability, balance, standardization

The following paper deals with a model for reuse of software providing different levels of reuse intensity. The model is designed for industrial use based on experiences from consulting a large inhouse developer (administrative software). It is drawn from state-of-the-art suggestions in reuse research as well as from typical constraints of time and costs in a less ideal development scenario. The model can be taken as a receipt for reuse in practice as it provides three different levels of reuse intensities/investments, and thus returns three different levels of reuse maturity. A basic level of reuse maturity in practice is to achieve maintainability: Many, especially older, programs turn out to be widely undocumented; often requirements and/or abstract design are missing, the programs do not meet basic criteria of maintainability. A medium level of reuse maturity is represented by balance within similar projects: A well designed and therefore maintainable software system contains system-specific and general components. We define a group of software systems as balanced, if there is a clear top-down structure from the general to the specific in documents concerning analysis, design, code and test. A new but similar system can be designed reusing upper level components and adapting lower level ones. A top-level reuse maturity in practice affords several technical and organizational efforts. We favor the term reuse culture. The design of a new project goes along with the use of repositories for all phases of development. Making a reuse culture work needs developing, providing and enforcing of standards. On the technical level this requires the use of quality assurance methodology, on the organizational level this includes a rather precise project information flow model. The roles for a reuse culture are defined