MOD2-SCM: Experiences with co-evolving models when designing a modular SCM system

Software configuration management (SCM) is the discipline of controlling the evolution of large and complex software systems. Many tools and systems for SCM have been developed which are based on a variety of different version models. Usually, an SCM application is a single software system whose underlying architecture is implicitly defined by its implementation. MOD2-SCM, instead, is a modular and extendable SCM system whose components have been explicitly modeled. Each component is defined by a separate model which addresses a specific area of the SCM domain. These components are loosely coupled by extending a common core model. We describe how the architecture of MOD2-SCM has been designed to support the co-evolution of the various component models. Additionally, we discuss the difficulties we experienced when it comes to the co-evolution of the common core model and the component models.