- In 1965 Bell Laboratories joins with MIT and General Electric in the development of a new operating system, Multics, which would provide multiuser, multi-processor, and multi-level (hierarchical) file system, among its many forward-looking features.
- In 1969, some of the AT&T Bell Labs programmers (Ken Thompson, Dennis Ritchie, Rudd Canaday, and Doug McIlroy), designed and implemented the first version of the Unix File System on a PDP-7 along with a few utilities. It was given the name UNIX by Brian Kernighan as a pun on Multics.
- 1970, Jan 1 time zero for UNIX
- In 1973, Unix was rewritten in C (a new language developed by Dennis Ritchie). This made possible for Unix to be installed and run on many different types of computers which had a C compiler
- AT&T gave Unix to the Universities for research. The first one was University of California at Berkeley, that developed “Berkeley Unix” or BSD (Berkeley Standard Distribution)