Software Evolution Observations Based on Product Release History

Large software systems evolve slowly but constantly. In this paper we examine the structure of several releases of a telecommunication switching system (TSS) based on information stored in a database of product releases. We tracked the historical evolution of the TSS structure and related the adaptations made (e.g. addition of new features, etc.) to the structure of the system. Such a systematic examination can uncover potential shortcomings in the structure of the system and identify modules or subsystems that should be subject to restructuring or reengineering. Further, we have identified additional information that would be useful for such investigations but is currently lacking in the database. 1 Introduction The aging of software is a problem that is often neglected in software development. But the effects and the costs of aging software have become much clearer and subject to many discussions during the past years: Lehman and Belady discuss the laws of software evolution and th..