2Unix First Edition
5Unix System V
As Unix grew in popularity for big enterprises, most of the major hardware vendors felt it necessary to have their own distinct versions of Unix (pretty much defeating some of the earlier unification efforts). Hewlett-Packard’s HP-UX, based on Unix System V and still in use today, was designed to run HP’s mainframes and large server systems.
While not technically a Unix operating system (and usually referred to as Unix-like), Linux is certainly descended from and very similar to Unix. Created by Linux Torvalds, Linux provided a free and powerful operating system for anyone to use on standard hardware and to this day still drives much of the Web.
13Mac OS X
While Unix was always a huge success in the data center, it has never had much success on the desktop. Or has it? At the heart of Apple’s Mac OS X—considered by many to be the best desktop operating system available today—beats Darwin, a Unix operating system core descended from BSD and NextStep.