Evolving Existing Systems to Service-Oriented Architectures: Perspective and Challenges

The advent of and growing interest in service- oriented architectures (SOA) present business leaders with a number of problems. They promise to deliver hitherto unseen business process agility, but at the risk of making investment in existing systems obsolete. The established orthodoxy is that the maintenance problem presented by installed systems is about finding an acceptable balance between risk involved in evolving the system and benefits offered by the update. SOAs represent a "paradigm-shift" and, as such, present a more complicated problem: how to minimise the risk to their investment (existing software systems) and exploit the benefits of migrating to SOA. We provide a review of a number of approaches that may contribute to a pragmatic strategy for addressing the problem and outline the significant challenges that remain.