Why has UNIX become such a popular operating system? Thi section examines many of the reasons for the success of UNIX.
UNIX is "multi-user"
Unlike MS-DOS, OS/2, and Windows NT, UNIX is a multi-user operating system. This means that multiple users can log in to a computer at one time, and use the resources of that computer. Resources can be a machine’s CPU, it’s software applications, as well as it’s hard disk drives, printers, modems, etc.