Software Repositories in Ubuntu

Ubuntu uses software repositories to get information about available software that can be installed onto your system. By default, it only allows access to a small portion of software (even though this software is officially supported by Ubuntu). However, Ubuntu is based on a much older Linux distribution called Debian. Debian has access to more than 17,000 different packages, which means that Ubuntu can have access to these packages, too.

There are four major package repository types in Ubuntu.

• main - Supported by Canonical. This is the major part of the distribution.
• restricted - Software not licensed under the GPL (or similar software license), but supported by Canonical.
• universe - Software licensed under the GPL (or similar license) and supported by users.
• multiverse - Software not licensed under the GPL (or similar license), but supported by users.