Supporting Software Maintenance by Mining Software Update Records

To my father, mother and sister for their endless love and support I have yet to see any problem, however complicated, which, when you looked at it in the right way, did not become still more complicated. Poul Anderson (1926-2001) Science Fiction Writer It is well known that maintenance is the most expensive stage of the software life cycle. Most large real world software systems consist of a very large number of source code files. Important knowledge about different aspects of a software system is embedded in a rich set of implicit relationships among these files. Those relationships are partly reflected in system documentation at its different levels, but more often than not are never made explicit and become part of the expertise of system maintainers. Finding existing relations between source code components is a difficult task, especially in the case of legacy systems. When a maintenance programmer is looking at a piece of code in a source file, one of th