NetBSD Operating System
NetBSD is a free and open-source Unix-like operating system based on the Berkeley Software Distribution. It was the first open-source BSD descendant officially released after 386BSD was forked. It is a highly portable operating systems that can run on more than 55 CPU platforms includding: xen, amd64, evbarm, evbmips, evbppc, hpcarm, sparc64, alpha, amiga, atari, cobalt, emips, hpcmips, ia64, ibmnws, iyonix, macppc, sgimips, ...
FreeBSD Operating System
FreeBSD is a free and open-source Unix-like operating system descended from the Berkeley Software Distribution, which was based on Research Unix. Cutting edge features - offers advanced networking, performance, security and compatibility features today which are still missing in other operating systems, even some of the best commercial ones.
Open Solaris Operating System
OpenSolaris is an open source but proprietary (CDDL) computer operating system based on Solaris and created by Sun Microsystems. The project itself was discontinued but there are several forks of this operating system that have been continued and are modern and up-to-date: * OpenIndiana * Illumos * SmartOS * Oracle Solaris.