Unix is a computer operating system. Among other things, it allows a computer to do many things at once. Derivatives of the original Unix include Linux, MacOS, and BSD. You’re reading this right now due to a server running Unix derivative Linux.
Background
Dennis Ritchie and Ken Thompson worked at Bell Labs. Thompson worked on a powerful but extremely complex operating system called Multics, which never entirely worked. Eventually, Bell Labs abandoned Multics but Thompson remained intrigued with the technology.
Thompson started developing a vastly simplified version on his own, using a stray DEC PDP-7. No sooner did he develop basic functionality than he was joined by his friend and collaborator computer scientist Dennis Ritchie. Together, along with others who eventually joined, they finished.
Nobody remembers exactly who coined the name Unix but there was a broad consensus that the new operating system worked great. It was fast, reliable, stable, and relatively easy to program.
Unix Takes Off
Unix use grew organically. As Bell Labs purchased more DEC computers, operators chose to run Unix rather than DEC’s operating system, RT-11.
Version 2 of Unix included the C programming language, enabling the operating system to be more easily ported to various other computers. Because all software runs on an operating system, this enabled cross-platform software development. Specifically, software developers could write to an operating system that ran on a multitude of computers, a concept called system portability. This became vital in later years.
Unix also started an unspoken but very real war between the “hippies” – represented by Ritchie and Thompson – and the suits, represented by Intel, HP, DEC, and most other computer companies. The success of Unix led to the idea that wild-eyed long-haired software engineers, working with little or no planning, could produce something as good or better than their buttoned-down professionally-dressed counterparts.