Software archaeology

Software archaeology or software archeology is the study of poorly documented or undocumented legacy software implementations, as part of software maintenance. Software archaeology, named by analogy with archaeology, includes the reverse engineering of software modules, and the application of a variety of tools and processes for extracting and understanding program structure and recovering design information. Software archaeology may reveal dysfunctional team processes which have produced poorly designed or even unused software modules. The term has been in use for decades, and reflects a fairly natural metaphor: a programmer reading legacy code may feel that he or she is in the same situation as an archaeologist exploring the rubble of an ancient civilization.

A workshop on Software Archaeology at the 2001 OOPSLA (Object-Oriented Programming, Systems, Languages & Applications) conference identified the following software archaeology techniques, some of which are specific to object-oriented programming:

More generally, Andy Hunt and Dave Thomas note the importance of version control, dependency management, text indexing tools such as GLIMPSE and SWISH-E, and "[drawing] a map as you begin exploring."

Like true archaeology, software archaeology involves investigative work to understand the thought processes of one's predecessors. At the OOPSLA workshop, Ward Cunningham suggested a synoptic signature analysis technique which gave an overall "feel" for a program by showing only punctuation, such as semicolons and curly braces. In the same vein, Cunningham has suggested viewing programs in 2 point font in order to understand the overall structure. Another technique identified at the workshop was the use of aspect-oriented programming tools such as AspectJ to systematically introduce tracing code without directly editing the legacy program.

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