FreeBSD
There are many uses for the operating system FreeBSD, but we know FreeBSD especially for its reputation as a stable server operating system. Some of the servers in the 2006 /dev/null/nethack tournament used FreeBSD, as do the ascension.run and em.slashem.me public servers. (Compare FreeBSD with Debian, the OS behind nethack.alt.org.)
The FreeBSD Ports Collection is the easy way to install software onto FreeBSD, turning your machine into a nice web server or KDE box, for example. The other BSD operating systems forked their ports collections from FreeBSD. Two packages interesting to NetHack players are freebsd-games (for Hack, Larn, and Rogue) and nethack36. FreeBSD's base system shipped with Hack until version 5, where it was moved to the freebsd-games port.[1]
A unique feature of FreeBSD is the jail. A jail has its own IP address and cannot see any files outside of the jail. Perhaps this convinced some tournament admins to use FreeBSD as a NetHack server, not another BSD or Unix. By locking the ssh or telnet server-daemon and NetHack in a jail, should there be a problem in security, the intruder is unable to attack anything outside of the jail.
FreeBSD supports fewer hardware platforms than NetBSD and OpenBSD.
