Source: History of Unix

The history of Unix dates back to the mid-1960s when the Massachusetts Institute of Technology, AT&T Bell Labs, and General Electric were jointly developing an experimental time-sharing operating system called Multics for the GE-645 mainframe.Multics introduced many innovations, but had many problems.

Bell Labs, frustrated by the size and complexity of Multics but not the aims, slowly pulled out of the project. Their last researchers to leave Multics – Ken Thompson, Dennis Ritchie, Doug McIlroy, and Joe Ossanna among others – decided to redo the work on a much smaller scale. In 1979, Dennis Ritchie described their vision for Unix.

and from there the Journey Started ...