Pruning and Polishing: Keeping OpenBSD Modern Ted Unangst <tedu@openbsd.org> AsiaBSDCon 2015 Owing to its historic roots as a derivative of the original Berkeley Systems Distribution (BSD), OpenBSD includes a great deal of old code. Many files bear copyright notices from the year 1980, and in some cases, even older. Although not explicitly stated as a project goal, keeping OpenBSD modern is an important part of satisfying other goals, such as portability and correctness. To that end, something must be done about all the legacy code that we have inherited. Actually, two somethings, pruning and polishing . In this paper, I'll explain what I mean by these terms, how the OpenBSD Project goes about pruning and polishing, and lessons learned in the process. Simply put, pruning is deleting code. I use the term pruning to encompass more than just the simple act of deleting code, but al...