Explicit representation of variability in software product family assets

Motivated by problems resulting from the implicit and varying representation of variability in software product families, this paper discusses an approach to represent variability in product family assets in an explicit and more homogeneous way. The focus of the paper is on the Variability Specification Language (VSL), an XML-based language to specify variation points in product family assets. Besides the language itself, the paper also contains an outline of the underlying variability meta-model, some illustrative case studies and lessons learned during the management of variability with and within XML.