Design requirements for an architecture consistency tool

Software architecture and its related documentation are acknowledged as some of the most important artefacts created during system design. However, often the implemented system diverges, over time, from the designed architecture. This phenomenon is called architectural drift and is either a result of inconsistent evolution of the system, or a failure to keep the architectural documentation up to date. A case study, performed at IBM, over two years showed how architectural drift can occur in small development teams over time. It suggested that even when approaches are in place to identify architectural drift, they may prove insufficient for subsequent removal of the drift, and some possible reasons for this were derived. Consequently, this document outlines the resultant design requirements for an approach to inhibit architectural drift, primarily by identifying it as, or before, it is introduced.