Redocumentation of a legacy banking system: an experience report

Successful software systems need to be maintained. In order to do that, deep knowledge about their architecture and implementation details is required. This knowledge is often kept implicit (inside the heads of the experts) and sometimes made explicit in documentation. The problem is that systems often lack up-to-date documentation and that system experts are frequently unavailable (as they got another job or retired). Redocumentation addresses that problem by recovering knowledge about the system and making it explicit in documentation. Automating the redocumentation process can limit the tedious and error-prone manual effort, but it is no 'silver bullet'. In this paper, we report on our experience with applying redocumentation techniques in industry. We provide insights on what (not) to document, what (not) to automate and how to automate it. A concrete lesson learned during this study is that the "less is more" principle also applies to redocumentation.