Linux is an open source operating system - the code which drives a computer and provides the main interface through which a user controls it. As it's open source, the source code is available to download by anyone - without paying royalties or signing prohibitive contracts - allowing others to inspect, and even modify, the way it works.

Its growing popularity can be attributed to its performance, reliability and security, its free source code and being in the right place at the right time. When compared with using proprietary operating systems such as Microsoft Windows, Linux has saved - and will save - organisations worldwide millions of dollars.

Linus Torvalds created the Linux kernel (the heart of an OS) in 1991 whilst a post-graduate student in Helsinki. Torvalds posted his code on the Internet and invited developers from around the world to improve it. The source code was provided, free of charge, with the proviso that other developers share their work back to the community.

Developers enthusiastically accepted Torvald's invitation, whilst others combined it with other open source software to form a complete operating system, including web browsers, word processors and so on.

Today, Linux is a highly regarded OS and continues to evolve through contributed efforts of the worldwide development community. Used by millions, in all industries, it is the world's fastest-growing operating system; but controlled through collaboration rather than imposition.

IBM is a vital player in this revolution with key members of the open source community - including Linux kernel developers - working at IBM sites around the world.

IBM isn't entirely altruistic, of course, so how does a company make money out of a product which is free?

As the Linux kernel source code is freely available, many different groups (including some companies) have developed different distributions of Linux. A distribution is a complete system that bundles the kernel, other parts of the operating system and a number of additional software packages such as utilities, desktop productivity applications, programming tools, games and so on. Typically, a purchased distribution will also include a written manual.

There is no standard distribution, and each has its unique advantages. A variety of utilities, services and various applications can be included, depending on its intended use.

Although the source code to the Linux kernel - and many of the programs bundled with it - are free, a distribution may not be. Companies and developers can sell distributions as long as the free source code is still available. By bundling other applications (which may not be open source), providing installation CDs and documentation, companies can charge for their efforts and make money. They can also make money by providing technical support services, either on-site or via telephone. Some distributions can be downloaded at no cost, but a fee is payable for official technical support.

IBM profits from promoting Linux by selling additional software, hardware services and financing contracts to customers using Linux systems. Those customers, in turn, use Linux systems as the total cost of ownership (TCO) tends to be lower - allowing them to save money, or make more profit.

Linux also complements IBM's goal of promoting open standards and interoperability: it's easier and cheaper to develop and maintain software to run on one OS than many.

Modern Linux distributions, featuring the GNOME and KDE desktops, are on the verge of being usable by the average home computer user, and are certainly suitable for technically-adept computer users. Digital cameras, MP3 players, word processing, spreadsheets, CD burning, web browsing and games are all well catered for on top of an OS which tends to be more stable, secure and cheaper than its more popular counterparts.

Linux's inherent security - including the philosophy of doing things in a well understood and secure manner in, for example, e-mail clients - means that Linux users are much safer than Windows users regarding "malware", such as viruses, spyware and email worms.

More information on Linux, including a list of Linux distributions and what IBM's doing with Linux in detail can be found in the links below:
  //www.ibm.com/linux
  http://www.linux.org