Software evolution and the staged model of the software lifecycle.

The aim of this chapter is to describe the new staged model [5]. We provide a broad overview of the state of the art in software maintenance and evolution. The emphasis is mainly on process and methods, (rather than technology), since this is where the main developments have occurred, and is of most relevance to this chapter. There is much useful material available on software maintenance management, including very practical guides [6]. We start from the foundations established within the international standards community. We then briefly revisit previous research work, as an understanding of these results is essential. Program comprehension is identified as a key component; interestingly, very few textbooks on software engineering and even on software maintenance mention the term, so our review of the state of the art addresses the field to include this perspective. The new model and our view of research areas are influenced by program comprehension more than other aspects. The staged model is presented, and evidence drawn from case studies. Practical implications are then described, and finally, research directions are presented