There are many different branches of Debian, especially since there are stable releases of the program about every 18-20 months. The different packages that are in one branch can become too old for the user's software and preferences. To counter this, the testing and unstable branches have to include the recent package versions that users of Debian might still enjoy using. The repositories constantly update the older package versions in both the stable and oldstable areas with the more modern versions, or they continue to include the packages that don't follow the Debian guidelines.
When it comes to the branches of Debian, the oldstable, codenamed Sarge, is the previous stable release. It will continue to be supported until one year after a new release is out. Debian usually asks users to upgrade to the new stable when it has been released. The current release, codenamed Etch, is stable and very well tested. Stable branches are made by freezing testing for several months so that bugs can be fixed in order to make the distribution as easy, and stable, as possible. Once this is done, the system that results from it is as stable as it can be, so it is released as the latest stable version. This new version is only updated if a major security problem is reported or if there are usability fixes that have to be made in the programming or software packages. Users of Debian can find the latest stable version's CDs or DVDs on the Debian web site at www.debian.org.
The next branch that is currently in testing, is codenamed Lenny. It will be the next major release and is being tested now. The different packages that will be included in this branch still have some testing that is in the unstable branch, and they may not be fit for release right now. Lenny currently has more modern software packages than the current stable branch, but the older, current branch is still updated continuously. The stable branch can be upgraded to testing, but it cannot be placed back in unstable. So, security updates for the testing distribution version are still created and provided by the Debian security team. Users can also find the testing and security CDs and DVDs on Debian's web site.
The unstable branch, codenamed Sid, is the repository that contains the packages that are still in developments, and it is always being updated. These software packages can easily be retrieved from the unstable repository through any Debian web site and then can be used to upgrade any system at any time. But, users should not expect that the system is as usable or stable as the other, more well-tested branches of the operating system. The repository is mainly for Debian developers who are participating in a specific project and who need access to the latest libraries and branches that are available.
The sixth part of this series will take you through the different repositories – the official repository, the semi-official repository, and the unofficial repository.