Before diving right into the technology, let us have a look at what the Debian Project is, its objectives, its means, and its operations.
Debian is a GNU/Linux and GNU/kFreeBSD distribution. We will discuss what a distribution is in further detail in
Section 1.5, “The Role of Distributions”, but for now, we will simply state that it is a complete operating system, including software and systems for installation and management, all based on the Linux or FreeBSD kernel and free software (especially those from the GNU project).
When he created Debian, in 1993, under the leadership of the FSF, Ian Murdock had clear objectives, which he expressed in the Debian Manifesto. The free operating system that he sought would have to have two principal features. First, quality: Debian would be developed with the greatest care, to be worthy of the Linux kernel. It would also be a non-commercial distribution, sufficiently credible to compete with major commercial distributions. This double ambition would, in his eyes, only be achieved by opening the Debian development process just like that of Linux and the GNU project. Thus, peer review would continuously improve the product.
1.1.1. A Multi-Platform Operating System
Debian, remaining true to its initial principles, has had so much success that, today, it has reached a tremendous size. The 13 architectures offered cover 11 hardware architectures and 2 kernels (Linux and FreeBSD). Furthermore, with more than 17,300 source packages, the available software can meet almost any need that one could have, whether at home or in the enterprise.
The sheer size of the distribution can be inconvenient: it is really unreasonable to distribute 70 CD-ROMs to install a complete version on a standard PC… This is why Debian is increasingly considered as a “meta-distribution”, from which one extracts more specific distributions intended for a particular public: Debian-Desktop for traditional office use, Debian-Edu for education and pedagogical use in an academic environment, Debian-Med for medical applications, Debian-Junior for young children, etc. A more complete list of the subprojects can be found in the section dedicated to that purpose, see
Section 1.3.3.1, “Existing Debian Sub-Projects”.
These partial views of Debian are organized in a well-defined framework, thus guaranteeing hassle-free compatibility between the various “sub-distributions”. All of them follow the general planning for release of new versions. And since they build on the same foundations, they can be easily extended, completed, and personalized with applications available in the Debian repositories.
All the Debian tools operate in this direction: debian-cd has for a long time now allowed the creation of a set of CD-ROMs containing only a pre-selected set of packages; debian-installer is also a modular installer, easily adapted to special needs. APT will install packages from various origins, while guaranteeing the overall consistency of the system.
1.1.2. The Quality of Free Software
Debian follows all of the principles of Free Software, and its new versions are not released until they are ready. Developers are not forced by some set schedule to rush to meet an arbitrary deadline. People frequently complain of the long time between Debian's stable releases, but this caution also ensures Debian's legendary reliability: long months of testing are indeed necessary for the full distribution to receive the “stable” label.
Debian will not compromise on quality: all known critical bugs are resolved in any new version, even if this requires the initially forecast release date to be pushed back.
1.1.3. The Legal Framework: A Non-Profit Organization
Legally speaking, Debian is a project managed by an American not-for-profit, volunteer association. The project has around a thousand Debian developers, but brings together a far greater number of contributors (translators, bug reporters, artists, casual developers, etc.).
To carry its mission to fruition, Debian has a large infrastructure, with many servers connected across the Internet, offered by many sponsors.
