Revisiting Legacy Software System Modernization

Legacy software systems are those that significantly resist modification and evolution while still being valuable to its stakeholders to the extent that their failure has a detrimental impact on business. Despite several drawbacks of legacy software systems, they are still being extensively used in real life. Over the years, a plethora of methods and techniques has been proposed to facilitate legacy software system modernization. These methods and techniques are predominately focused on technical aspects and ignore business aspects of modernization. Furthermore, research indicates that legacy software modernization methods reported in academia are too abstract to adopt in industry and 97% of the academic approaches do not fit the industrial purposes. In this dissertation, we develop and validate a software modernization method that combines technical and business aspects of software modernization to SOA. Furthermore, this dissertation also identifies how legacy software systems and their modernization are perceived in industry. This research uses empirical methods to investigate why legacy systems are still prevalent in industry and what challenges practitioners face in software modernization. The research reported in this dissertation contributes to the scientific and industry community. To the scientific community, this research adds to the body of knowledge of software evolution by delivering a structured software modernization method. This research also provides an insight into how industry values their legacy systems and what challenges industry face while modernizing. These challenges can be viewed as future research direction for the scientific community. Finally, this research facilitates technology and knowledge transfer between academia and industry in legacy software system modernization domain