Ubuntu focuses on
usability[25] and
security. The Ubiquity installer allows Ubuntu to be installed to the hard disk from within the Live CD environment, without the need for restarting the computer prior to installation. Ubuntu also emphasizes
accessibility and
internationalizationto reach as many people as possible. Beginning with 5.04,
UTF-8 became the default
character encoding,
[26] which allows for support of a variety of non-Roman scripts. As a security feature, the
sudo tool is used to assign temporary privileges for performing administrative tasks, allowing the root account to remain locked, and preventing inexperienced users from inadvertently making catastrophic system changes or opening security holes.
[27] PolicyKit is also being widely implemented into the desktop to further harden the system through the
principle of least privilege.
Installation
Installation of Ubuntu is generally performed with the
Live CD. The Ubuntu OS can be run directly from the CD (albeit with a significant performance loss), allowing a user to "test-drive" the OS for hardware compatibility and driver support. The CD also contains the
Ubiquity installer,
[30] which then can guide the user through the permanent installation process.
CD images of all current and past versions are available for download at the Ubuntu web site.
[31] Installing from the CD requires a minimum of 256 MB
RAM.
Users can download a disk image (.iso) of the CD, which can then either be written to a physical medium (CD or DVD), or optionally run directly from a hard drive (via
UNetbootin). Ubuntu is even available on the
PowerPC platform (enabling users of older Macintosh computers to run Ubuntu natively on their machines); however, it is no longer officially supported.
Canonical offers Ubuntu
[32] and Kubuntu
[33] installation CDs at no cost, including paid postage for destinations in most countries around the world (via a service called ShipIt).
A
Microsoft Windows migration tool, called Migration Assistant (introduced in April 2007),
[34] can be used to import bookmarks,
desktop background (wallpaper), and various settings from an existing MS Windows installation into a new Ubuntu installation.
[35]
Ubuntu and Kubuntu can be booted and run from a
USB Flash drive[36](as long as the
BIOS supports booting from USB), with the option of saving settings to the flashdrive. This allows a portable installation that can be run on any PC which is capable of booting from a USB drive.
[37]In newer versions of Ubuntu, the
USB creator program is available to install Ubuntu on a
USB drive (with or without a LiveCD disc).
Wubi, which is included as an option on the Live CD,
[38] allows Ubuntu to be installed and run from within a virtual Windows
loop device (as a large image file that is managed like any other Windows program via the
Windows Control Panel). This method requires no
partitioning of a Windows user's
hard drive. Wubi also makes use of the Migration Assistant to import users' settings. It is only useful for Windows users; it is not meant for permanent Ubuntu installations and it also incurs a slight performance loss.
Remastering
Package classification and support
Ubuntu divides all software into four domains to reflect differences in licensing and the degree of support available.
[39] All unsupported applications receive updates from community members, but not from
Canonical.
| free software | non-free software |
| supported | Main | Restricted |
| unsupported | Universe | Multiverse |
Free software includes only software that has met the Ubuntu licensing requirements,
[40] which roughly correspond to the
Debian Free Software Guidelines. Exceptions, however, include
firmware and
fonts, in the Main category, because although they are not allowed to be modified, their distribution is otherwise unencumbered.
[41]
Non-free software is usually unsupported (Multiverse), but some exceptions (Restricted) are made for important non-free software. Supported non-free software includes device drivers that can be used to run Ubuntu on some current hardware, such as binary-only
graphics card drivers. The level of support in the Restricted category is more limited than that of Main, because the developers may not have access to the
source code. It is intended that Main and Restricted should contain all software needed for a general-use Linux system. Alternative programs for the same tasks and programs for specialized applications are placed in the Universe and Multiverse categories.
In addition to the above, in which the software does not receive
new features after an initial release,
Ubuntu Backports is an officially recognized project to
backportnewer software from later versions of Ubuntu.
[42] The repository is not comprehensive; it consists primarily of user-requested packages, which are approved if they meet quality guidelines. Backports receives no support at all from Canonical, and is entirely community-maintained.
The
-updates repository provides updates to stable releases of Ubuntu and are generally installed through update-manager. Each release is given its own -updates repository (e.g. intrepid-updates). The repository is supported by
Canonical for packages in main and restricted, and by the community for packages in universe and multiverse. All updates to the repository must meet certain requirements and go through the
-proposed repository before being made available to the public.
[43]Updates will continue to be available until the end of life for the release.
In addition to the -updates repository, the unstable
-proposedrepository contains uploads which must be confirmed before being copied into -updates. All updates must go through this process to ensure that the patch does truly fix the bug and there is no risk of
regression.
[44] Updates in -proposed are confirmed by either Canonical or members of the community.
Availability of third-party software
Additionally, several third party application suites are available for purchase through the Canonical web-based store, including software for DVD playback and media codecs.
Releases
There are two Ubuntu releases per year, using the year and month of the release as the
version number. The first Ubuntu release, for example, was Ubuntu 4.10 and was released on October 20, 2004.
[51]Version numbers for future versions are provisional; if the release is delayed the version number changes accordingly.
Ubuntu releases are also given
code names, using an adjective and an animal with the same first letter (e.g., "Dapper Drake" and "Intrepid
Ibex"). With the exception of the first three releases, code names are in alphabetical order, allowing a quick determination of which release is newer. Commonly, Ubuntu releases are referred to using only the adjective portion of the code name.
[52]
Releases are timed to be approximately one month after GNOME releases (which in turn are about one month after releases of
X.org). Consequently, every Ubuntu release comes with an updated version of both GNOME and X. Selected releases (such as
6.06 Dapper Drake and
8.04 Hardy Heron) have been labeled as Long Term Support (LTS) versions, indicating that they are supported (with updates) for three years on the desktop and five years on the server,
[53] as compared to the 18-month support period for non-LTS releases.
[54]
The current release is
9.10 Karmic Koala,
[55] released on October 29, 2009. Some users have reported hardware-recognition and functionality issues on upgrading to this version from previous versions of Ubuntu.
[56] However, statistics based on the main Ubuntu support forum shows that the number of problems with 9.10 is no worse than average.
[57]
System requirements

Kubuntu is an official variant of the Ubuntu distribution which uses
KDErather than
GNOME Several official and unofficial Ubuntu variants exist. These Ubuntu variants install a set of packages that differ from the original Ubuntu distribution.
Official variants store packages and updates in the same
repositories as Ubuntu, so that the same software is available for each of them and is generally compatible between the official variants. The Ubuntu derivatives that are fully supported by Canonical are:
[10]
The following are Canonical-sponsored derivatives:
[61]
Development
TheUbuntu Developer Summit is a gathering of software developers which occurs prior to the release of a new public version of Ubuntu.
At the beginning of a new development cycle, Ubuntu developers from around the world gather to help shape and scope the next release of Ubuntu. The summit is open to the public, but it is not a conference, exhibition or other audience-oriented event. Rather, it is an opportunity for Ubuntu developers, who usually collaborate online, to work together in person on specific tasks.
Reception
In an August 2007 survey of 38,500 visitors on DesktopLinux.com, Ubuntu was the most popular distribution with 30.3% of respondents claiming to use it.
[7]
In January 2009, the
New York Times reported that Ubuntu had over ten million users and in June 2009
ZDNet reported, "Worldwide, there are 13 million active Ubuntu users with use growing faster than any other distribution."
[71][72]
Jamie Hyneman, co-host of the television series
Mythbusters, has advocated Linux, specifically giving the example of Ubuntu, as an alternative to proprietary software, citing
software bloat as a major hurdle in proprietary operating systems.
[78][79]
Ubuntu has also received negative assessments. In early 2008
PC Worldcriticized the lack of an integrated desktop effects manager, although this did not prevent them from naming Ubuntu the "best all-around Linux distribution available today".
[80]
The Ministry of Education and Science of
Macedonia deployed more than 180,000 Ubuntu Linux based classroom desktops, and has encouraged every student in the country to use Ubuntu-powered computer workstations.
[81]
The French police is in the process of installing Ubuntu on 90,000 workstations, demonstrating a 70% saving on the IT budget without having to reduce its capabilities.
[82]
Vendor support
A number of vendors offer computers with Ubuntu pre-installed, including
Dell,
[83]Tesco,
[84] OP3, Gliese IT,
System76,
[85] and the South African company Bravium Computers.
[86] Dell and System76 customers are able to choose between 30-day, three-month, and yearly Ubuntu support plans through Canonical.
[87] Dell computers (running Ubuntu 8.04 or 9.04) include extra support for
ATI Video Graphics, Dell Wireless,
Fingerprint Readers,
HDMI,
Bluetooth, DVD Playback (using
LinDVD), and
MP3/
WMA/
WMV.
[88]