Linux 
An open-source operating system that runs on a number of hardware platforms, including PCs, Macintosh computers, and servers from Hewlett-Packard and IBM. The Linux kernel was developed in 1990 by Linus Torvalds at the University of Helsinki in Finland; the operating system and its associated applications were developed by a loose network of programmers worldwide. Several companies and organizations have developed their own Linux distributions (popularly known as distros), which contain the operating system plus enhancements and applications such as office suites, games, e-mail clients, and so on. The average price for these distributions is $25 to $80, making Linux much less expensive than Windows or Macintosh operating systems. Popular distros include Mandrake and Red Hat. This operating system has made inroads into corporate life, particularly as an inexpensive substitute for high-priced Unix Web servers.