Re-engineering for Evolvability Considering social as well as technical requirements for software products

Today’s software products are used by a number of organisations to serve their businesses. The software is often customised to support a variety of needs and uses in an organisation. Over time, software has evolved to support changes in the way it is used. The challenge for the software to maintain its Evolvability—that is, its adaptability and at the same time its sustainability with respect to the way it is used and further developed—deserves serious consideration in academia and industry. The goal of this research is to propose engineering discipline for enhancing continuous evolvability. The research is designed as a qualitative empirical study using two case studies—DHI Water Environment and Health (DHI) and EASI-WAL, an open source project let by a Belgian government agency—that re-engineer their software products using software product line approach, and an interview study with different product developing companies. The study with DHI took place over a time span of 2.5 years as an action research project. The study with EASI-WAL triangulates the first one; the research took place during a three-month stay in Belgium. The interview study was performed as yet another triangulation in order to see whether the observed practices in the two cases studies can be observed in other organisations as well. The two case studies (a long-term involvement and a short-term involvement case study) centre on the re-engineering of socially embedded systems in which the design and evolution depend on usage, development cooperation, and changes to the technical base. Based on the initial empirical research, an evolvability framework is identified that contains six contextual dimensions (business context, use context, software engineering organisation, software engineering practice, technical infrastructure, and technical selection) which need to be considered when evolving the software product in a sustainable manner. The research highlights architectural changes and changes to the architectural practice when introducing a product line approach. E.g. to promote awareness of architecture in everyday development, the build hierarchy in DHI was changed to represent the design architecture and thus promote the alignment of design and code architecture.