A decade ago, Ubuntu was a word that shook apartheid South Africa. Today, it is a word that may be keeping Bill Gates awake at night.

Ubuntu is an African word that is one of the founding principles of the new South Africa, and it also is the name of a new computer operating system developed by South African Mark Shuttleworth and his company Canonical.

The word "Ubuntu is very difficult to render into a Western language," writes Archbishop Desmond Tutu in "No Future Without Forgiveness." It means "you are generous, you are hospitable, you are friendly and caring and compassionate. You share what you have."

Ubuntu Linux calls itself the "Linux for human beings". In less than six months from its introduction in October 2004, Ubuntu Linux became the most popular Linux desktop distribution in the United States.

In July, PC World magazine named Ubuntu Linux one of its "100 Best Products of 2005". And it has won numerous other awards. A special version was developed by Hewlett-Packard for its laptop computers that are sold in Europe, the Middle East and Africa.

Linux is a computer operating system, the software that makes a computer work. The operating system most commonly found on desktop computers in an office, at school or at home is Microsoft's Windows.

The second most common desktop operating system is Apple's MacOS, which at 4.5 percent of the market in the United States is a distant second. Linux is third at about 3.5 percent of the desktop computers.

That's not insignificant though -- it means that about one of every 28 computers in the United States is using Linux, and outside the U.S. the figure is much bigger.

Government agencies and local governments in Germany, Spain, Sweden Brazil and China have already changed from Windows to Linux. New Linux usage is picking up and its use on the desktop in the U.S. is expected to reach six percent in 2007.

Linux has been described as the most popularly used operating system that most users don't know that they use every day.'s search engine is driven entirely on a giant Linux cluster., eBay and a great many other Web sites are run on Linux systems.

But Linux has not been as popular on desktop systems. There are many reasons for this, starting with the fact that almost every computer comes with the operating system already installed and unless you make a special request, you won't get Linux on your computer.

Ubuntu Linux has been successful where others have failed, helping to take Linux into a significant segment of users much like that held by Apple's Macintosh.

Part of Ubuntu's success has to do with its design. To understand the significance of this, you have to unravel one of the mysteries of Linux.

Linux, unlike Windows or the MacOS, is software that is distributed under a Free Software Foundation license. The core of the operating system, called the kernel, is really the only part that of the system that is Linux. A Linux distribution takes that kernel and adds a great many additional software programs and utilities to make the whole system.

One common misunderstanding about Linux is to think that free software means that the work of developing it is being done for free. All the developers of the Linux operating system are being paid full-time wages. Most are employed by the giants of the computer industry like Hewlett-Packard and IBM. IBM alone has over 600 programmers working full-time on Linux development.

These corporations have chosen to be a part of the Linux development because some experts in the field of computer technology think that free, open source software can be more stable and secure than closed, proprietary systems. Linux has convinced many that this can be true.

Ubuntu Linux is built on one of the most stable and secure Linux distributions, adding an installer that is at least as easy to use as the Windows installer. The result has been described as "Grandpa's Linux" -- that is, it is the Linux you would put onto a computer for someone who needs an easy-to-use system.

Which leads to another reason Ubuntu Linux has been successful. It is a community-based distribution.

If you look underneath Ubuntu Linux, you'll find another name in Linux systems: Debian. Debian calls itself the "free software community" and its collection of Linux software emphasises stability and security.

Ubuntu Linux is actively part of that free software community. This has made it attractive to users in school systems, where having access to completely free software can make a difference.

At Yorktown High School in Arlington, Virginia, they are using Ubuntu Linux, says Jeff Elkner, a computer science teacher at the school. He says that one reason they've chosen Ubuntu is because it is based on the Debian distribution.

Debian is essential, Elkner says, because it is not subject to commercial pressure and therefore has long-term stability. In addition, "There is more free software packaged [for free download from the Internet] for Debian than for any other [Linux distribution], so Ubuntu users have access to all that software."

Elkner is one of the developers of Edubuntu, a Ubuntu distribution customised for use in schools. It is already being used at Yorktown High School and is expected to be released for general use in October.

At an Edubuntu Summit in July in Australia, educators from every continent came together. Reports from the summit indicate that Edubuntu will soon be found in hundreds of schools across Europe from Sweden to Spain -- in the state of Andalusia the government has chosen Ubuntu Linux for its schools, libraries and all public facilities. In Brazil, Elkner says, more than a million pupils will be using Edubuntu.

China, India and South Africa are also countries where Ubuntu Linux user communities have developed.

Finally, Ubuntu Linux is successful because it has strong financial backing.

In July, Mark Shuttleworth and Canonical set up the Ubuntu Foundation with 10 million dollars in financing. The money comes from Shuttleworth's deep pockets.

Shuttleworth came by his fortune by founding Thawte, a highly successful Internet security company that was an early seller of the digital certificates needed for online commerce. He sold the company for a reported 575 million dollars in 1999. After the sale, Shuttleworth spent 20 million dollars to be a space tourist on a Russian Soyuz rocket, spending eight days at the International Space Station orbiting Earth.

Back on land, he has put some of his fortune into developing Linux systems. His funding of the Ubuntu Foundation guarantees that Ubuntu Linux will have a stable future.

"The Ubuntu Foundation is a non-profit fund setup to ensure that a few core Ubuntu developers can be employed full-time for a few years, making good on commitments for long-term support for existing Ubuntu releases and also coordinating new Ubuntu releases," said Shuttleworth.

"So it allows people to be confident that Ubuntu won't go away, no matter what happens to me or to Canonical, the company behind Ubuntu."