Product families and process families

Product lines or families represent an important way of organizing software products. Product families might include, for example, successive revisions of a single application, versions of an application for different host platforms, or versions with varying features, e.g., different levels of security. A software product family can thus be viewed as a collection of products that are similar in some important respects yet systematically different in others. The family viewpoint emphasizes both the commonality among family members and the differences between them, and it draws attention to their interrelationships. Our work in software processes has lead us to conclude that software processes also can be usefully viewed in terms of families. As software process engineers, we also naturally view products in terms of the processes that create them and, conversely, we view processes in terms of the products they create. This suggests that product families and process families should be closely interrelated. Consequently, both products and processes may benefit from analysis in terms of families and family relationships. We begin to sketch out such an analysis and some of the issues that it raises.