Where Did UNIX Come From and Why Are There Different Versions Of UNIX? The first efforts at developing a multi-user, multi-tasking operating system were begun in the 1960's in a development project called MULTICS. While working for Bell Telephone Laboratories in 1969 and 1970, Ken Thompson and Dennis Ritchie began to develop their own single-user, multi-tasking small operating system and they chose the name UNIX. Their initial goal was simply to operate their DEC PDP machines more effectively. In 1971, UNIX became multi-user and multi-tasking, but it was still just being developed by a small