From System Comprehension to Program Comprehension

Program and system comprehension are vital and expensive parts of the software maintenance process. In this paper, we discuss the need for both perspectives and describe two methods that may be integrated to provide a smooth transition in understanding from the system level approach to the program level. The first part of this paper presents the results from a qualitative survey of expert industrial software maintainers, extracting from these results their information needs when comprehending software. Then we critically review existing software tools which can be used to facilitate system level and program comprehension. Two successful methods from the fields of data mining and concept assignment are discussed, each addressing some of these requirements. Results from each method are given. Finally, we describe how these methods can be coupled to produce a more comprehensive software comprehension method which partly satisfies all the requirements. Future directions including the closer integration of the techniques are also identified.