GNU/Linux is an operating system: a series of programs that let you interact with your computer and run other programs. An operating system consists of various fundamental programs which are needed by your computer so that it can communicate and receive instructions from users; read and write data to hard disks, tapes, and printers; control the use of memory; and run other software. The most important part of an operating system is the kernel. In a GNU/Linux system, Linux is the kernel component. The rest of the system consists of other programs, many of which were written by or for the GNU Project. Because the Linux kernel alone does not form a working operating system, we prefer to use the term GNU/Linux to refer to systems that many people casually refer to as Linux. GNU/Linux is modelled on the Unix operating system. From the start, GNU/Linux was designed to be a multi-tasking, multi-user system. These facts are enough to make GNU/Linux different from other well-known operating systems. However, GNU/Linux is even more different than you might imagine. In contrast to other operating systems, nobody owns GNU/Linux. Much of its development is done by unpaid volunteers. Development of what later became GNU/Linux began in 1984, when the Free Software Foundation began development of a free Unix-like operating system called GNU. The GNU Project has developed a comprehensive set of free software tools for use with Unix™ and Unix-like operating systems such as GNU/Linux. These tools enable users to perform tasks ranging from the mundane (such as copying or removing files from the system) to the arcane (such as writing and compiling programs or doing sophisticated editing in a variety of document formats). While many groups and individuals have contributed to GNU/Linux, the largest single contributor is still the Free Software Foundation, which created not only most of the tools used in GNU/Linux, but also the philosophy and the community that made GNU/Linux possible. The Linux kernel first appeared in 1991, when a Finnish computing science student named Linus Torvalds announced an early version of a replacement kernel for Minix to the Usenet newsgroup comp.os.minix. See Linux International's Linux History Page. Linus Torvalds continues to coordinate the work of several hundred developers with the help of a number of subsystem maintainers. There is an official website for the Linux kernel. Information about the linux-kernel mailing list can be found on the linux-kernel mailing list FAQ. GNU/Linux users have immense freedom of choice in their software. For example, they can choose from a dozen different command line shells and several graphical desktops. This selection is often bewildering to users of other operating systems, who are not used to thinking of the command line or desktop as something that they can change. GNU/Linux is also less likely to crash, better able to run more than one program at the same time, and more secure than many operating systems. With these advantages, Linux is the fastest growing operating system in the server market. More recently, Linux has begun to be popular among home and business users as well.