Which documentation for software maintenance?

software engineering has been striving for years to improve the practice of software development and maintenance. documentation has long been prominent on the list of recommended practices to improve development and help maintenance. recently however, agile methods started to shake this view, arguing that the goal of the game is to produce software and that documentation is only useful as long as it helps to reach this goal. on the other hand, in the re-engineering field, people wish they could re-document useful legacy software so that they may continue maintain them or migrate them to new platform. in these two case, a crucial question arises: how much documentation is enough? in this article, we present the results of a survey of software maintainers to try to establish what documentation artifacts are the most important to them.