Structuring large versioned software products

A discussion is presented of the solutions proposed by the Nomade project: a language-independent kernel and a specialized tool. The kernel manages coarse-grained objects (from files to abstractions such as modules or subsystems), while the tool manages fine-grained objects (basically the external objects of modules: procedures types, etc.). Concepts and properties of variants and revisions are defined. The kernel, enforcing these properties, allows tools to work safely in a monoversioned context. One of these tools, mainly dedicated to interface control, is then presented