Guide to Unix/BSD
Berkeley Software Distribution or BSD is a flavor of UNIX that was developed at the University of California, Berkeley. Today, the BSD or *BSD systems are free Unix-like operating systems based on the university's distribution. To honor this, these systems put BSD at the end of their names. The *BSD systems are DragonFly BSD, FreeBSD, NetBSD, and OpenBSD.
- FreeBSD: focuses on speed and performance.
- Mac OS X: Darwin and BSD
- NetBSD: focuses on portability
- OpenBSD: focuses on code correctness (and thus security) and easy to security
- Historical: BSD operating systems that have been unmaintained or abandoned.