Introducing Adaptivity to Achieve Longevity for Software

Long living software systems (LLSSs) must provide the flexibility to react to changes in their operating environment as well as to changes in the user’s requirements, even during operation. Self-adaptive software systems (SASSs) face adaptivity at runtime within predefined bounds. Yet, not all types of necessary variations can be anticipated and unforeseen changes to software may happen. Thus, systems that are meant to live in such an open-ended world must provide self-adaptivity (micro adaptation), but there is an additional need for adaptability of the system so that it can be adjusted externally (macro adaptation). This paper gives an overview of the graphbased runtime adaptation framework (GRAF) and sketches how it targets both types of adaptation.