As Eden and Turner observe [7], a peculiar aspect of software, with respect to other information artifacts such as laws or recipes, is its bridging role between the abstract and the con- crete: despite the fact that it has an abstract nature, it is designed to produce specific results in the real world. Therefore, it seems natural to us to adopt a requirements engi- neering perspective while analyzing the essence of software, looking at the whole soft- ware engineering process, including requirements analysis, instead of focusing on computational aspects only.