DECODE: a cooperative environment for reverse-engineering legacy software

While automated program understanders have had some success in partially extracting design information from source code, they are unlikely to be able to completely understand existing real-world legacy systems. To address this problem, we have been developing DECODE, an environment in which programmer and system cooperate to extract object-oriented designs from legacy systems. DECODE consists of three components: an automated program understander that extracts some initial stereotypical object-oriented design elements; a structured notebook that provides the user with a graphical view of the system´s understanding and the ability to extend this understanding by linking source code fragments to object-oriented design elements; and a query processor that uses this design information to support conceptual queries about the program´s code and design. This paper describes DECODE and our initial successes and failures with using it to reverse engineer several non-trivial COBOL programs