Complete operating systems drawn from the original BSD core. Some are based off of each other, rather than the original, and have varying kernel internals unlike Linux, which uses the same core kernel. All share POSIX-compliance, although FreeBSD is reported to have some quirks, and most of the same command structure such as ls, rm, mkdir, df, etc. similar to other UNIX-like systems.
Most of these distributions are freely available over the Internet and can be easily downloaded and installed. As mentioned on the BSD page: these distributions are not easy to operate and not for casual computer users; there is a learning curve associated with BSD but has a strong reputation for being robust and fast.
BSD history is detailed by Kirk McKusick in Twenty Years of Berkeley Unix: From AT&T-Owned to Freely Redistributable.
- DesktopBSD - for beginners
- FreeBSD - Focusing on features and ease of use
- Darwin (OS X) - Focusing on the desktop and multimedia with use of the Apple's Aqua Interface
- NetBSD - Focusing on portability
- OpenBSD - Focusing on security
- DragonflyBSD - Focusing on new computing paradigms
- PC-BSD Focusing on the desktop a branch of FreeBSD