Kubuntu is an official derivative of the Ubuntu operating system using the KDE graphical environment instead of GNOME. It is part of the Ubuntu project and uses the same underlying system. It is possible to run both the KDE desktop (kubuntu-desktop) as well as the Gnome desktop (ubuntu-desktop) interchangeably on the same machine. Every package in Kubuntu shares the same repositories as Ubuntu.[1] Kubuntu CDs can be ordered through the Shipit service. It is released regularly and predictably on the same schedule as Ubuntu.
Differences from Ubuntu
A regular installation of Ubuntu will have the GNOME desktop, GNOME applications (e.g. Evolution) and GNOME/GTK+ admin tools (e.g. Synaptic Package Manager). A regular installation of Kubuntu has the KDE desktop, KDE applications (e.g. Kontact) and KDE/Qt admin tools (e.g.KPackageKit). In addition, Kubuntu is more likely to use packages from the KDE/Qt project rather than GTK+ toolkit-based applications. However, these are simply the default packages. For example, one may install Ubuntu and then add KDE, or even install the Kubuntu 'metapackage' itself. Therefore, one need not be restricted to one set of applications, but can mix and match by preference. (There is a slight disadvantage to doing so, namely the increased diskspace and memory requirements of running both Qt and GTK.)
Releases
Kubuntu follows the same naming/versioning system as Ubuntu, with each release having a code name, and a version number based on the year and month of release. Canonical provides support and security updates for most Kubuntu versions for 18 months after release.[4] Both Desktop CDs and Alternative (installation) CDs for x86 and AMD64 platforms are available.
Kubuntu is available both with KDE 3.5 and KDE 4.
source = wikipedia.org
