A Brief History of the UNIXes
Here is a timeline of events that triggered the Unix revolution starting from Multics to OpenSolaris
1965: Bell Labs, GE, MIT start working on the Multics Time Sharing System
1966: Kenneth Thompson finishes his Master's Degree in Electrical Engineering from UCB and joins Bell Labs
1968: Dennis MacAlistair Ritchie finishes his Doctorate from Harvard and joins the Multics team at Bell Labs
1969: Bell Labs pulls out of Multics Project. Thompson begins writing UNICS in assembly language
1970: Digital Electronic Corporation ships the PDP-11 and Bell Labs gets one of them
1971: UNIX gains popularity inside Bell Labs and people start using it
1972: UNIX is re-written in the C programming language paving way for portability to different computers.
1974: UCB gets UNIX version 4 and starts making improvments to it
1975: AT&T begins licensing Unix to Universities
1978: Bill Joy rolls out BSD unix from Berkeley.
1979: Microsoft licenses UNIX from AT&T and distributes XENIX
[Thank god XENIX was not a hit. Just imagine if it had been ! Everyone would be saying that Microsoft Created UNIX ]