A.1. Census and Cooperation
The Debian project fully acknowledges the importance of derivative distributions and actively supports collaboration between all involved parties. This usually involves merging back the improvements initially developed by derivative distributions so that everyone can benefit and long-term maintenance work is reduced.
This explains why derivative distributions are invited to become involved in discussions on the debian-derivatives@lists.debian.org mailing-list, and to participate in the derivative census. This census aims at collecting information on work happening in a derivative so that official Debian maintainers can better track the state of their package in Debian variants.
→ http://wiki.debian.org/DerivativesFrontDesk
→ http://wiki.debian.org/Derivatives/Census
Let us now briefly describe the most interesting and popular derivative distributions.
A.2. Ubuntu
Ubuntu made quite a splash when it came on the Free Software scene, and for good reason: Canonical Ltd., the company that created this distribution, started by hiring thirty-odd Debian developers and publicly stating the far-reaching objective of providing a distribution for the general public with a new release twice a year. They also committed to maintaining each version for a year and a half for both core and security-related components.
These objectives necessarily involve a reduction in scope; Ubuntu focuses on a smaller number of packages than Debian, and relies primarily on the GNOME desktop (although an official Ubuntu derivative, called “Kubuntu”, relies on KDE). Everything is internationalized and made available in a great many languages.
So far, Ubuntu has managed to keep this release rhythm. They also publish Long Term Support (LTS) releases, with a 5-year maintenance promise. As of April 2012, the current LTS version is version 12.04, nicknamed Precise Pangolin. The latest non-LTS version is 11.10, nicknamed Oneiric Ocelot. Version numbers describe the release date: 11.10, for example, was released in October 2011.
Ubuntu has reached a wide audience in the general public. Millions of users were impressed by its ease of installation, and the work that went into making the desktop simpler to use.
However, not everything is fine and dandy, especially for Debian developers who placed great hopes in Ubuntu contributing directly to Debian. Even though this situation has improved over the years, many have been irked by the Canonical marketing, which implied Ubuntu were good citizens in the Free Software world simply because they made public the changes they applied to Debian packages. Free Software proponents understand that an automatically-generated patch is of little use to the upstream contribution process. Getting one's work integrated requires direct interaction with the other party.
This interaction is becoming more common over time, thanks in part to the Ubuntu community and the efforts it makes in educating its new contributors. But this policy is still not enforced by Canonical on its employees. Some kept true to their roots, and do make the required effort (Colin Watson, Martin Pitt and Matthias Klose are noteworthy in this regard), but others — often overworked — can no longer find it in them.
→ http://www.ubuntu.com/
A.3. Knoppix
The Knoppix distribution barely needs an introduction. It was the first popular distribution to provide a LiveCD; in other words, a bootable CD-ROM that runs a turn-key Linux system with no requirement for a hard-disk — any system already installed on the machine will be left untouched. Automatic detection of available devices allows this distribution to work in most hardware configurations. The CD-ROM includes almost 2 GB of (compressed) software.
Combining this CD-ROM and a USB stick allows carrying your files with you, and to work on any computer without leaving a trace — remember that the distribution doesn't use the hard-disk at all. Knoppix is mostly based on LXDE (a lightweight graphical desktop), but many other distributions provide other combinations of desktops and software. This is, in part, made possible thanks to the live-build Debian package that makes it relatively easy to create a LiveCD.
→ http://live.debian.net/
Note that Knoppix also provides an installer: you can first try the distribution as a LiveCD, then install it on a hard-disk to get better performance.
→ http://www.knopper.net/knoppix/index-en.html
A.4. Linux Mint
Linux Mint is a (partly) community-maintained distribution, supported by donations and advertisements. Their flagship product is based on Ubuntu, but they also provide a “Linux Mint Debian Edition” variant that evolves continuously (as it's based on Debian Testing). In both cases, the initial installation involves booting a LiveDVD.
The distribution aims at simplifying access to advanced technologies, and provides specific graphical user interfaces on top of the usual software. For instance, even though Linux Mint relies on GNOME, it provides a different menu system; similarly, the package management interface, although based on APT, provides a specific interface with an evaluation of the risk from each package update.
Linux Mint includes a large amount of proprietary software so as to ensure the best possible user experience. For example: Adobe Flash and multimedia codecs.
→ http://www.linuxmint.com/
A.5. SimplyMEPIS
SimplyMEPIS is a commercial distribution very similar to Knoppix. It provides a turn-key Linux system from a LiveCD, and includes a number of non-free software packages: device drivers for nVidia video cards, Flash for animations embedded in many websites, RealPlayer, Sun's Java, and so on. The goal is to provide a 100 % working system out of the box. Mepis is internationalized and handles many languages.
→ http://www.mepis.org/
This distribution was originally based on Debian; it went to Ubuntu for a while, then came back to Debian, which allows its developers to focus on adding features without having to stabilize packages coming from Debian's Unstable distribution.
A.6. Aptosid (Formerly Sidux)
This community-based distribution tracks the changes in Debian Sid (Unstable) — hence its name — and tries to release 4 new versions each year. The modifications are limited in scope: the goal is to provide the most recent software and to update drivers for the most recent hardware, while still allowing users to switch back to the official Debian distribution at any time.
→ http://aptosid.com
A.7. Damn Small Linux
This distribution provides a tiny LiveCD, weighing only 50 MB, so that it can fit on a CD-ROM with the shape and size of a business card. This can be useful for using Debian on an aging computer.
→ http://www.damnsmalllinux.org/
A.8. And Many More
The Distrowatch website references a huge number of Linux distributions, many of which are based on Debian. Browsing this site is a great way to get a sense of the diversity in the Free Software world.
→ http://distrowatch.com
The search form can help track down a distribution based on its ancestry. In January 2012, selecting Debian led to 141 active distributions!
→ http://distrowatch.com/search.php
Appendix B. Short Remedial Course
Even though this book primarily targets administrators and “power-users”, we wouldn't like to exclude motivated beginners. This appendix will therefore be a crash-course describing the fundamental concepts involved in handling a Unix computer.
B.1. Shell and Basic Commands
In the Unix world, every administrator has to use the command line sooner or later; for example, when the system fails to start properly and only provides a command-line rescue mode. Being able to handle such an interface, therefore, is a basic survival skill for these circumstances.