Techniques for independent deployment to build product populations

When building small product families, software should be shared between different members of the family, but the software can still be created as one system (with variation points) with a single architecture. For large and diverse product families (product populations), the software can no longer be developed in one context and at one moment in time. Instead, one must combine software components of which the development is separated in space and in time, each with their own evolution path. In other words, we need independent deployment of components. We discuss four aspects of independent deployment. Two of these aspects: upward and downward compatibility, deal with variation in time. The other two: reusability and portability, deal with variation in space. For each aspect, we indicate the relevance, provide some examples, and list several techniques to deal with it. The paper can thus be seen as a guide for product population development.