| Year | Event |
| 1957 | Bell Labs found they needed an operating system for their computer center that at the time was running various batch jobs. The BESYS operating system was created at Bell Labs to deal with these needs. |
| 1965 | Bell Labs was adopting third generation computer equipment and decided to join forces with General Electric and MIT to create Multics (Multiplexed Information and Computing Service). |
| 1969 | By April 1969, AT&T made a decision to withdraw Multics and go with GECOS. When Multics was withdrawn Ken Thompson and Dennis Ritchie needed to rewrite an operating system in order to play space travel on another smaller machine (a DEC PDP-7 [Programmed Data Processor 4K memory for user programs). The result was a system that a punning colleague called UNICS (UNiplexed Information and Computing Service)--an 'emasculated Multics'. |
| 1969 | Summer 1969 Unix was developed. |
| 1969 | Linus Torvalds is born. |
| 1971 | First edition of Unix released 11/03/1971. The first edition of the "Unix PROGRAMMER'S MANUAL [by] K. Thompson [and] D. M. Ritchie." It includes over 60 commands like: b (compile B program); boot (reboot system); cat (concatenate files); chdir (change working directory); chmod (change access mode); chown (change owner); cp (copy file); ls (list directory contents); mv (move or rename file); roff (run off text); wc (get word count); who (who is one the system). The main thing missing was pipes. |
| 1972 | Second edition of Unix released December 06, 1972. |
| 1972 | Ritchie rewrote B and called the new language C. |
| 1973 | Unix had been installed on 16 sites (all within AT&T/Western Electric); it was publically unveiled at a conference in October. |
| 1973 | Third edition of Unix released February 1973 |
| 1973 | Forth edition of Unix released November 1973 |
| 1974 | Fifth edition of Unix released June 1974 |
| 1974 | Thompson went to UC Berkeley to teach for a year, Bill Joy arrived as a new graduate student. Frustrated with ed, Joy developed a more featured editor em. |
| 1975 | Sixth edition of Unix released May 1975 |
| 1975 | Bourne shell is introduced begins being added onto. |
| 1977 | 1BSD released late 1977 |
| 1978 | 2BSD released mid 1978 |
| 1979 | Seventh edition of Unix released January 1979 |
| 1979 | 3BSD released late 1979 |
| 1979 | SCO founded by Doug and Larry Michels as Unix porting and consulting company. |
| 1980 | 4.0BSD released October 1980 |
| 1982 | SGI introduces IRIX. |
| 1983 | SCO delivers its first packaged Unix system called SCO XENIX System V for Intel 8086 and 8088 processor-based PCs. |
| 1983 | The GNU operating system is first announced by Richard Stallman September 27, 1983. |
| 1984 | Ultrix 1.0 was released. |
| 1985 | Eighth edition of Unix released February 1985 |
| 1985 | The GNU manifesto is published in the March 1985 issue of Dr. Dobb's Journal. The GNU project starts a year and a half later. |
| 1986 | HP-UX 1.0 released. |
| 1986 | Ninth edition of Unix released September 1986 |
| 1987 | Sun and AT&T lay the groundwork for business computing in the next decade with an alliance to develop Unix System V Release 4. |
| 1988 | HP-UX 2.0 released. |
| 1988 | HP-UX 3.0 released. |
| 1989 | SCO ships SCO Unix System V/386, the first volume commercial product licensed by AT&T to use the Unix System trademark. |
| 1989 | HP-UX 7.0 released. |
| 1989 | Tenth edition of Unix released October 1989 |
| 1990 | AIX short for Advanced Interactive eXecutive was first entered into the market by IBM February 1990. |
| 1991 | Sun unveils Solaris 2 operating environment, specially tuned for symetric multiprocessing. |
| 1991 | Linux is introduced by Linus Torvalds, a student in Finland. |
| 1991 | HP-UX 8.0 released. |
| 1991 | BSD/386 ALPHA First code released to people outside BSDI 12/xx/1991 |
| 1992 | HP-UX 9.0 released. |
| 1993 | NetBSD 0.8 released 04/20/1993 |
| 1993 | FreeBSD 1.0 released December of 1993 |
| 1994 | Red Hat Linux is introduced. |
| 1994 | Caldera, Inc was founded in 1994 by Ransom Love and Bryan Sparks. |
| 1994 | NetBSD 1.0 released 10/26/1994 |
| 1995 | FreeBSD 2.0 released 01/xx/1995 |
| 1995 | SCO acquires Unix Systems source technology business from Novell Corporation (which had acquired it from AT&T's Unix System Laboratories). SCO also acquires UnixWare 2 operating system from Novell. |
| 1995 | HP-UX 10.0 released. |
| 1995 | 4.4 BSD Lite Release 2 the true final distribution from the CSRG 06/xx/1995 |
| 1996 | KDE is started to be developed by Matthias Ettrich |
| 1997 | HP-UX 11.0 released. |
| 1997 | Caldera ships OpenLinux Standard 1.1 May 5, 1997, the second offering in Caldera's OpenLinux product line |
| 1998 | IRIX 6.5 the fifth generation of SGI Unix is released July 6, 1998. |
| 1998 | SCO delivers UnixWare 7 operating system. |
| 1998 | Sun Solaris 7 operating system released. |
| 1998 | FreeBSD 3.0 released 10/16/1998 |
| 2000 | FreeBSD 4.0 released 03/13/2000 |
| 2000 | Caldera Systems Inc. announces that Caldera Systems has entered into agreement to acquire the SCO Server Software Division and the Professional Services Division. |
| 2001 | Linus Torvalds releases version 2.4 of the Linux Kernel source code on January 4th. |
| 2001 | Microsoft files a trademark suit against Lindows.com in December. |
| 2004 | Lindows changes it's name to Linspire April 14, 2004. |
| 2004 | The first release of Ubuntu is released October 20, 2004. |
