Software reuse is the most promising way to build large software systems with certifiable quality as well as reduced cost and time. Reactive reuse - i.e. the random reuse of artifacts from previous developments - has proven to be inefficient for many reasons. Product line development combines development for reuse and development with reuse in a pro-active sense. A priori, commonalities and variabilities of a family of systems are identified, an invariable architecture is chosen supporting all the variabilities, and reusable components are provided. Then applications are developed with reuse of the invariable architecture based on a product map. This approach repeats in software engineering what other engineering disciplines have adopted as professional standard for a long time.

Fraunhofer IESE has developed the PuLSE approach for product line engineering, and has transferred it to companies in various sectors of industry. The effects include tremendous gains in quality, cost and time. On average, the upfront investment in product line infrastructures (i.e., development for reuse) is recovered after three application developments at most. This presentation will introduce the key ingredients of the PuLSE approach, survey several industrial applications, and end with a list of lessons learned.