Doing some research on the early days of Unix, and have some question marks. Hope you can help me clarify:

Multics was designed by Bell, AT&T, MIT. Bell withdrew from the project and Ken Thompson (an employee at Bell) had set out to build an alternative. Also it is said the motivation was to run 'Space Travel', the game he was developing on a cheaper machine and that he looked for hardware to build it on.

This story sounds very entrepreneurial of Ken, pursuing his ideas even when Bell, his employer decided not to. How did the product of Ken's initiative came to be the property of AT&T? It is also said that later on Bell's Ken and Dennis Richie worked on additional parts like the file system, and other components that later became unix. Didn't Bell quit the project? How did AT&T got the rights to it all?

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    @GypsyCosmonaut it’s on-topic here too. – Stephen Kitt Jul 4 '17 at 12:53
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    @itaysk have you read the Wikipedia page on the topic? Also note that Bell Labs was part of AT&T. – Stephen Kitt Jul 4 '17 at 12:54
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    At many companies, what you produce during work hours and/or with company resources, belongs to the company. – Kusalananda Jul 4 '17 at 12:56
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    I'd say webarchive.loc.gov/all/20100506231949/http://cm.bell-labs.com/… has most of the information you're looking for – Stéphane Chazelas Jul 4 '17 at 13:03
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    Sorry if off topic, but there's a 'history' tag that is about: 'The history of Unix systems and their main components. Please DO NOT USE this tag for shell-related questions; use "command-history" instead.' So I figured it fits. I did read the Wikipedia page, that's where I got most of the background. So what we say is that although Bell had quit the project, and Ken & Dennis continued, being indirectly employed by AT&T gave them the rights to the product... OK Makes sense. – itaysk Jul 4 '17 at 13:05

This answer is according to my understanding. Comment if you find corrections.

Q. How did the product of Ken's initiative came to be the property of AT&T?


  1. Ken Thompson was employee (1966 to 2000) of Bell Labs and
  2. Bell Labs was partly owned by AT&T

According to history of Bell Labs at for 1925 – 1984:

In 1925 Western Electric Research Laboratories and part of the engineering department of the American Telephone & Telegraph company (AT&T) were consolidated to form Bell Telephone Laboratories, Inc. The ownership of Bell Laboratories was evenly split between AT&T and the Western Electric Company,...

Q. Didn't Bell quit the project? How did AT&T got the rights to it all?

Well, Bell quit the project MAC which was associated with MIT not AT&T.

So, since Ken was working for Bell Labs which is partly owned by AT&T, AT&T could impose its rights on Ken's work. If Ken had quit Bell Labs, he could have released his work Unix as he wish.

PS: To avoid this type of licensing restriction, Richard Stallman quit his MIT job:

Leaving MIT was necessary so that MIT would not be able to interfere with distributing GNU as free software. If I had remained on the staff, MIT could have claimed to own the work, and could have imposed their own distribution terms, or even turned the work into a proprietary software package.

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