Many companies regard mixing open and closed source in a product as a risky enterprise. Often this leads to a very limited use of open source. Consequently, these companies lock themselves out from all the available high-quality software and don’t benefit from the reduced costs and time to market that open source software implies.

In principle open source is appropriate for those features that complement the differentiating features of a product. But using open source for all non-differentiating components can be a step too far. Identifying the right candidates for open source requires a good analysis of the product and a careful cooperation between engineers and legal departments.

By taking license implications into account during the software design process, it is possible to use open source for certain features and use closed, in-house developed or commercially licensed software for other features, obtaining the best of both worlds.

The presentation will use Philips' ABISS hard-disk scheduler (http://abiss.sourceforge.net/), which Philips contributed to the Linux kernel, as a case study to illustrate this approach. By carefully formulating not only the technical but also legal design goals, Philips was able to allow any application to use the ABISS functionality yet use proprietary scheduling algorithms.