In 1985, Richard Stallman released "The GNU Manifesto," in which he proclaimed a golden rule: One must share computer programs. Software vendors required him to agree to license agreements that forbade sharing programs with others, but he refused to "break solidarity" with other computer users whom he assumed also wanted to use free software.

Debian is a free operating system (OS) for your computer. An operating system is the set of basic programs and utilities that make your computer run. At the core of an operating system is the kernel. The kernel is the most fundamental program on the computer: It does all the basic housekeeping and lets you start other programs.

Imagine a different way of computer life. For 80% of your computer-using time, you carry a usb key as your notebook computer You come to a foreign place and are allowed to use an unfamiliar computer. The computer may work perfectly or it may have been rendered non-bootable by a virus. It may be a powerful one or it may be an inexpensive netbook. It may speak Zulu or Tamil.

The kernel is a piece of software that, roughly speaking, provides a layer between the hardware and the application programs running on a computer. In a strict, computer-science sense, the term 'Linux' refers only to the kernel - the bit that Linus Torvalds wrote in the early 90s.

"A GNU/Linux computer operating system that contains only free software—software you are free to run, inspect, share, and modify—is out and ready for you to try on your ordinary PC (Intel or AMD-based computer)..."

"...So here’s hoping you’ll install and use more free software! What programs could you use? There are too many free software programs to mention them all, but you can visit the FSF/UNESCO Free Software Directory or try these favorites of mine (which happen to be on my computer as I type this)..."

"Lawyers have successfully managed to argue that computer programs are not mathematics and thus should not be covered by the exclusion of mathematics from patentable material. This comes from a deep misunderstanding of how computers really work – particularly as implementations of a universal turing machine. Some great papers on this have been written – including this one at groklaw.

"A working group has been set up in January 7th, 2002 by APRIL and FSF France. The original idea is from Pierre Jarillon (ABUL president). The objective is to have Free Software classified as an intangible world cultural heritage by the UNESCO

Richard Shipman, Teaching Fellow at the Computer Science department of Aberystwyth University, has extensive experience of working with Free Software and discussing its strengths and weaknesses with others.