Linux is a modular operating system. It derives much of its basic design from principles established in Unix






Linux uses a monolithic kernel, the Linux kernel, which handles process control, networking, peripheral and file system access. The primary difference between Linux and many other popular contemporary operating systems is that the Linux kernel and other components are free and open source software. Linux is not the only such operating system, although it is the best-known and most widely used.

Linux has mainly been used as a server operating system, and has risen to prominence in that area; Netcraft reported in September 2006 that eight of the ten most reliable internet hosting companies ran Linux on their web servers. (As of June 2008, linux represented five of ten, FreeBSD three of ten, and Microsoft two of ten.) This is due to its relative stability and long uptime, and the fact that desktop software with a graphical user interface for servers is often unneeded. Enterprise and non-enterprise Linux distributions may be found running on servers. Linux is the cornerstone of the LAMP server-software combination (Linux, Apache, MySQL, Perl/PHP/Python) which has achieved popularity among developers, and which is one of the more common platforms for website hosting.