Linux

In computing, non-proprietary operating system based on an original core program written by Linus Torvalds, a 22-year-old student at the University of Helsinki, Finland, in 1991-92. Linux is made up of freely available (‘open source’) code created over several years by Unix enthusiasts all over the world. Each programmer retains the copyright to his or her creation, but makes it freely available on the Internet.

Linux retains the flexibility and many of the advanced programming features that make Unix popular for technically minded users, but can run on an ordinary PC instead of an expensive Unix workstation.

In 2001, IBM invested US$1 billion in integrating Linux into its PC, laptop, mid-range, and mainframe product lines. At the end of 2003, the SCO Group wrote to Fortune 1000 companies advising them that certain versions of Linux violated SCO's rights in Unix, which it had purchased in the 1990s.