Types of Repositories
December 10, 2008 3 Comments
Many linux distributions divide their repositories into different parts based on certain criteria. It could be for support, policy, or anything else. I have tried to understand what kinds of repositories are out there for some distributions, and have always had a hard time remembering what is what. So I will provide a brief introduction here and link to more information. I hope you find this a good stepping stone to complete understanding.
Ubuntu
Ubuntu has four types of repositories: main, restricted, universe, and multiverse. Main contains free software which the Ubuntu distribution fully supports. Restricted may hold software which may not be free (or open source) but Ubuntu supports it. Universe contains open source software but it is not officially supported b Ubuntu. There is no guarantee for even security updates. Multiverse contains software which is absolutely not “free” and the advice is to use this at your own risk.
Debian
Debian has three main types of repositories: main, contrib, and non-free. There is a third-party unofficial apt repository and a multimedia packages repository.
Fedora
Fedora has three main types of repositories: base, updates, and extras. Base contains software which make up the actual Fedora distribution on a disc. Updates contains updates to the packages in base. Additional software is provided in extras. Apart from these official types of repositories, there are some third-party repositories which are not officially supported by Fedora project. These include, but are not limited to, RPMforge, Livna, Fresh RPMs, and ATrpms.
CentOS
CentOS has many types of repositories: os, updates, extras, addons, centosplus, and contrib. As with Fedora, the same third-party repositories may be used. There is another repository, called Extra Packages for Enterprise Linux (EPEL) which aims to provide packages not included in the main CentOS repositories. And then there are additional repositories.
Code Ghar 
The main repo for Fedora for things not in Fedora’s own repos is RPMfusion (rpmfusion.org). It was formed when Livna and others combined. It contains packages that can’t be in the Fedora repos mainly due to licencing issues, Fedora has a free only policy.
Where is Slackware, GoblinX and others in the list?
Certainly other distributions should be discussed. But my main interest lies in a handful of Linux distributions, plus Windows, FreeBSD, and (Open)Solaris. This is why I usually only post about them. You and anyone else interested in providing knowledge related to their favorite distribution is always welcome to contribute here.