Free software

Open Source software is not a technique like object programming, nor is it written in a particular programming language or designed for a specific platform. What defines it is of a different nature: its user license institutes a system of collective social ownership, authorizing everyone to access the source code, use it as they see fit, modify it and redistribute the results of these modifications. Through this "legal" invention, the founders of free software have made possible various models of shared software development. This has led to major achievements in fields as diverse as operating systems, graphical user interfaces, media technology, embedded software and cluster and grid computing. Specific innovations have emerged or been disseminated in the course of this movement, from development support to features such as peer-to-peer file sharing. Readers should therefore always bear in mind that, over and above any one remarkable achievement (the software that supports the Internet or the Web, the GNU/Linux operating system and its thousands of applications, for example), it is the creation and sharing mechanism that makes free software possible that deserves attention.

At present, a major debate is developing on a global scale: is free software a general model, destined to extend at least to all generic platforms and applications, or a mere societal curiosity aimed at passionate groups of users? This debate has political, social, cultural and economic dimensions that are beyond the scope of a technical encyclopedia. But it also has a technical dimension of its own. By giving the reader a general understanding of the mechanisms, achievements, advantages and technical difficulties of free software, this summary article aims to enable each reader to form his or her own opinion, and make the best use of the potential of this field.

The content of this article owes much to the European Free Software Working Group –, in particular paragraph 1, several extracts of which are simply translated or adapted from its report [1] –, and to the author's contacts with developers and users in Europe and beyond. They cannot all be quoted here, but the whole article is a tribute to their activity. Today, there are several hundred thousand free software developers in the world, tens of millions of conscious users, and each and every one of us is a user in one capacity or another of infrastructures and standards that would not exist without free software.

The opinions expressed in this text are those of the author and do not necessarily represent the official views of the European Commission. The author also maintains an online version of this text under the GNU Free Documentation License, which is intended to be amended, supplemented and updated....