Maintaining knowledge in system development

At any stage of the developing process of software systems a large mass of knowledge is produced which turns out to be useful at further stages. This is specially true in prototyping, where the various developing steps are not sharply distinct, that is they can often overlap both with respect to time and functionalities (i.e. the design phase plays also the role of specification, validation involves the execution phase, etc.). Thus, it becomes crucial to provide an integrated framework to maintain the knowledge related to different development steps all along the production of a software system.