digital computers , developed by Ken Thompson of Bell Laboratories in 1969.
It was initially designed for a single user (the name was a pun on the earlier operating system Multics). The C language was subsequently developed specifically for UNIX, and the system was rewritten almost entirely in C; it was improved by the addition of multiprogramming and time-sharing capabilities and enhanced portability. UNIX is very popular in universities, where it is used mostly on scientific and engineering workstations, and it is used on most of the servers of Internet service providers . Because its modular construction allows it to be easily modified, it has been improved in many ways by academic and industrial institutions (see {{link=Linux">Linux ).