Chapter 1. Welcome to Ubuntu 1.2.1.1. Package selection 1.2.1.2. Releases 1.2.1.3. Development community 1.2.1.4. Freedom and Philosophy Ubuntu does not provide security updates and professional support for every package available in the open source world, but selects a complete set of packages making up a solid and comprehensive system and provides support for that set of packages. For users that want access to every known package, Ubuntu provides a "universe" component (set of packages) where users of Ubuntu systems install the latest version of any package that is not in the supported set. Most of the packages in Ubuntu universe are also in Debian, although there are other sources for universe too. See the Ubuntu Components page for more detail on the structure of the Ubuntu web distribution. Ubuntu makes a release every six months, and supports those releases for 18 months with daily secu- rity fixes and patches to critical bugs. As Ubuntu prepares for release, we “freeze” a snapshot of Debian’s development archive (“sid”). We start from “sid” in order to give ourselves the freedom to make our own decisions with regard to release management, independent of Debian’s release-in-preparation. This is necessary because our release criteria are very different from Debian’s. As a simple example, a package might be excluded from Debian “testing” due to a build failure on any of the 11 architectures supported by Debian “sarge”, but it is still suitable for Ubuntu if it builds and works on only three of them. A package will also be prevented from entering Debian “testing” if it has release-critical bugs according to Debian criteria, but a bug which is release-critical for Debian may not be as important for Ubuntu. As a community, we choose places to diverge from Debian in ways that minimize the difference between Debian and Ubuntu. For example, we usually choose to update to the very latest version of Gnome rather than the older version in Debian, and we might do the same for key other pieces of infrastructure such as X or GCC. Those decisions are listed as Feature Goals for that release, and we work as a community to make sure that they are in place before the release happens. Many Ubuntu developers are also recognized members of the Debian community. They continue to stay active in contributing to Debian both in the course of their work on Ubuntu and directly in Debian. When Ubuntu developers fix bugs that are also present in Debian packages -- and since the projects are linked, this happens often -- they send their bugfixes to the Debian developers responsible for that package in Debian and record the patch URL in the Debian bug system. The long term goal of that work is to ensure that patches made by the full-time Ubuntu team members are immediately also included in Debian packages where the Debian maintainer likes the work. In Ubuntu, team members can make a change to any package, even if it is one maintained by some- one else. Once you are an Ubuntu maintainer it’s encouraged that you fix problems you encounter, although we also encourage polite discussions between people with an interest in a given package to improve cooperation and reduce friction between maintainers. Debian and Ubuntu are grounded on the same free software philosophy. Both groups are explicitly committed to building an operating system of free software. 3