Ubuntu and Debian
Ubuntu and Debian are closely related.
Ubuntu builds on the foundations of Debian's architecture and infrastructure, but there are important differences. Ubuntu has its own user interface, a separate developer community (though many developers participate in both projects) and a different release process.
Debian can be considered the rock upon which Ubuntu is built. It is a volunteer project that has developed and maintained a GNU/Linux operating system of the same name for well over a decade. Since its launch, the Debian project has grown to comprise more than 1,000 members with official developer status, alongside many more volunteers and contributors. Today, Debian encompasses over 20,000 packages of free, open source applications and documentation.
Ubuntu is an open source project that develops and maintains a cross-platform, open-source operating system based on Debian. It includes Unity, a consistent user interface for the smartphone, the tablet and the PC. Upgrades are released every six months and support is guaranteed by Canonical for up to five years. Canonical also provides commercial support for Ubuntu deployments across the desktop, the server and the cloud.