Unix Diagram

Explore the history and evolution of Unix operating systems


This diagram shows the evolution of operating systems who contributed to the Unix family.

The various arrows designate different links between systems:

  • a plain arrow is a successor to an operating system,
  • a dashed arrow is a system derived from another operating system,
  • a dotted arrow is a part of the code taken from a system to another operating system.


There are many Unix diagrams available on Internet, in magazines or books. Unfortunately the majority of them are incorrect, and contains important and commons mistakes. Many of them seems to refer to fancy sources of information.

Our goal with this diagram is to make a complete, true and simple diagram that describe the evolution of Unix. We attempt to make the truly diagram possible. That is why we take the information from the best sources we find.

The majority of informations present in this diagram were directly taken from official sources of operating systems themselves. It includes project websites, operating system documentation and source code. In other case, we directly ask our questions to peoples implied in the development of these systems.


This diagram was designed with the Graphviz software from AT&T Labs. It is an Open Source graph visualization software available on dozens of platforms.


This diagram was made by David du Colombier, with the help of Jean-Baptiste Campesato. This work was firstly published in April 2005 on 9grid.fr, then updated monthly. In July 2008, we opened unix-diagram.org.

Where is "Unics"?

On many websites, even the most serious, you can see references to "Unics", an operating system created by Ken Thompson in september 1969. We asked Dennis Ritchie about it, in september 2005. He affirms that term was never used, nor printed.

As far as we know, "Unics" was a proposition of name for the First Edition of Unix Time-Sharing System in 1971. But the name "Unix" was used instead. According to Dennis Ritchie, when Ken Thompson started to work on his operating system in 1969, it did not really have a name and was called something like "Ken's new system". We chose to use this term on our diagram.

"Unics" is a myth.


If you are interested in Unix history, we recommend you to read the book A Quarter Century of UNIX, wrote by Peter H. Salus and published by Addison-Wesley on June 10, 1994.

We can also recommend you to read Dennis Ritchie's historical papers on his Home Page.

Many old Unix operating systems are available on Unix Archive, thanks to The Unix Heritage Society.

The successor of Unix Time-Sharing System is Plan 9 from Bell Labs. It is actively developed by members of Bell Labs and a community of users. The authors of this diagram are members of the French community website 9grid.fr.


If you have some knowledge about Unix history, we are pleased to accept your contribution.

Despite the effort, this diagram is not perfect. Some errors might be present. If you find an error, we will be happy to correct it.


This diagram is available under the MIT license. It is a Free and Open Source license. Your are free to use, modify and distribute this diagram.


You can contact David du Colombier at the following e-mail address: .

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Last update: 2015-11-17