The task artifact cycle: a conceptual approach to maintenance and reengineering

We present a model-the so called task artifact cycle-which integrates the development of a system being in use into the software lifecycle. The basic assumption of the model is that the actual use of a system may considerably differ from the original design. This has to be taken into consideration in maintenance and reengineering. In particular, the monitoring of this development process is an important basis for maintainability.