Unix is the standard computer operating system of the World Wide Web. An operating system communicates messages from software such as your word processor or the WebCom Web Server to the hardware (the physical boards and chips) on which it is running. Other examples of operating systems are MS-DOS and OS/2 (from IBM). A computer must have an operating system running on it before it can do anything else.

Unix was originally designed by a pair of engineers at American Telephone and Telegraph. AT&T decided to let universities use it very cheaply. A research team at the University of California in Berkeley enhanced it and UCB was later awarded a government contract to add TCP/IP (Internet networking protocol software). Unix became very popular among university users, due to the power and flexibility of its design, which is very programmer friendly.

Since TCP/IP, the networking protocol of the Internet, has been built into Unix for decades (and thus is very robust and mature), and because of all the other benefits of Unix as a platform for multi-user software, UNIX naturally became the standard operating system for Internet servers as the Internet moved into wide use.