Integration of software systems - process challenges

The assumptions, requirements, and goals of integrating existing software systems are different compared to other software activities such as maintenance and development, implying that the integration processes should be different. But where there are similarities, proven processes should be used. We analyze the process used by a recently merged company, with the goal of deciding on an integration approach for three systems. We point out observations that illustrate key elements of such a process, as well as challenges for the future.