Unix is a mature multi-user operating system. Unix incorporates many strong features including true multitasking, virtual memory, shared libraries, demand loading, proper memory management, and TCP/IP networking. Unix is platform independent and can be installed on nearly any kind of machine, including Amiga, Digital Alpha, Intel, MIPS, Motorola, and Sun Sparc microprocessors.
The name "Unix" was intended as a pun on the mainframe OS called Multics (Multiplexed Information and Computing Service) and was written "Unics" at first (UNiplexed Information and Computing System).
The two first and biggest makers of Unix was Bell Labs and BSD.
Unix was first made by Ken Thompson and Dennis Ritchie at Bell-Labs.com in 1969. The original versions were called V1 (1971) through V7 (1979). By the 1980s Bell Labs had USL (Unix Systems Laboratories, which was majority-owned by AT&T) of Unix. Their versions were called System III (1982), System V (1983), SVR2 (1984), SVR3 (1986), SVR3.2 (merged with Xenix Unix) SVR4 (1988, merged with BSD Unix and SunOS). Since then the "original" Unix has gone from USL to Novell.com to Canopy.com to Caldera.com which bought SCO.com (Santa Cruz Operations) which also bought Xenix Unix from Microsoft.
The other big Unix developer early on was BSD (Berkeley Software Design, Inc.). Bill Joy and others created BSD while at Berkeley.edu. 2.xBSD (1978), 3BSD (1978), 4.0BSD (1980), 4.2BSD (1983), 4.3BSD (1986), 4.3 Reno (1990), 4.4BSD (1992).
Here are other makers and variations of Unix in no particular order. Usually the makers made proprietary versions of Unix for their hardware. Here are some.
A3000UX by Commodore.
A/UX by Apple in 1988. The precursor to Mac OS X.
AIX by IBM. Based on SVR2.
AOS by IBM. Based on 4.3BSD.
Dell Unix by Dell. Dell UNIX SVR3 was based upon source from ISC. Dell UNIX SVR4 was based upon source from AT&T/USL --including the predecessor to "plug and play".
HP/UX by Hewlett-Packard.
IRIX by SGI.
Minix. A free but closed source clone of Unix that inspired Linux.
OSF/1 (1991), Release 1.3 Unix (1994) by The Open Source Foundation.
Sinix by Siemens.
Solaris by Sun. A combination of SunOS 5.0, SVR4, and OpenWindows.
Unix has been going through a revival since the early 1990s when open-source variations of UNIX started becoming popular. The open-source variations of UNIX are developed by thousands of developers worldwide and is improved almost daily. The GUI of most variants are built on the X Window System. The most popular desktop environments are GNOME, KDE Plasma Desktop, and Cinnamon. Here are the major open source unix-like systems as of 2013:
Linux (or GNU/Linux)
Debian. 1993. Debian GNU/Linux. Debian project created by Ian Murdock at Purdue University. In 1996 Bruce Perens became the project lead.
Linux Mint Debian Edition (LMDE)
Kubuntu. KDE version.
Xubuntu. Xfe version.
Lubuntu. LXDE version.
Red Hat Enterprise Linux. Commercial.
Cromium OS. Open source.
Chrome OS. Commercial. Derived from Ubuntu then from Gentoo Linux.
SUSE Linux Enterprise
BSD. 1999. The license of the BSD UNIX was changed to open-source. FreeBSD.org.
NeXT NEXTSTEP and OPENSTEP
Mac OS X. Commercial.
386BSD. The first open source BSD-based OS and ancestor to most current BSD systems.
1983. Richard Stallman invented the concept of "Free Software" in response to his perception of restrictiveness at MIT.edu. His GNU project (GNU's Not Unix) is most famous for its free-source version of Unix. The GNU Hurd is the kernel of the GNU OS. The GNU project has grown from Gnu.org into the Free Software Foundation (FSF) [FSF.org]. The FSF considers Linux to be a derivative of the GNU OS, and would like "Linux" to be called "GNU/Linux".
1991. Linux created by Linus Torvalds at the University of Helsinki, Finland. Linux.org.The Linux kernel is one of the most influential of the open-source UNIX variants.
Feel free to pronounce Linux any way you want:
LEE-nooks is how Linus Torvalds pronounced Linux in an audio clip.
LIH-nucks is the most common American pronunciation.
Lynn-icks is you change the ending to match Unix.
Lie-nucks if you Americanize the pronunciation of "Linus" but change the "s" to an "x".
Crude estimates from various sources ca 2013:
All servers: 38%
Web servers: 66%
Desktop, laptop: 2% Linux,
Most popular version of Linux from various sources ca 2013: