Evolution in software product lines: Two cases

This paper discuss the results of two case studies from a technical perspective, concentrating on the evolution of software assets in two Swedish organizations that have employed a product-line architecture approach for several years. This paper describes and analyses the commonalities and differences of these two cases, emphasising categories of the evolution of the requirements, of the software architecture and of the software components. This paper concludes with three types of lessons learned about evolution in software product lines: three evolution categories are predominant, three other categories are less significant but still common, and seven guidelines for software product-line evolution emerge. Copyright (C) 1999 John Wiley & Sons, Ltd.