Since PDP-11 Unix became operational in February, 1971, over 600 installations have been put
– Dennis Ritchie and Ken Thompson, The
In the early years of the ARPANET in the 1970’s, Tenex/TOPS20 was the most widely used operating system on the network. However, since the 1980’s, variants of Unix have become the most widely used operating systems on the Internet.
Unix caused the creation of the popular C programming language, and helped establish Internet networking in academic environments. After spawning a number of somewhat incompatible varieties over the years, the Unix operating system family now shows signs of standardization on a free open source software version called Linux. The following subsections provide more information.