An operating system is the set of basic programs and utilities that make your computer run. Debian uses the Linux kernel (the core of an operating system), but most of the basic OS tools come from the GNU project; hence the name GNU/Linux.
The Debian Project is an association of individuals who have made common cause to create a free operating system. This operating system that we have created is called Debian GNU/Linux, or simply Debian for short.
An operating system is the set of basic programs and utilities that make your computer run. At the core of an operating system is the kernel. The kernel is the most fundamental program on the computer and does all the basic housekeeping and lets you start other programs.
If you are interested in giving Debian a try on your current computer without running any risk, please check out our Guide: Running Linux From a USB Drive As a Virtual Machine or Bootable Disk.
However, work is in progress to provide Debian for other kernels, primarily for the Hurd. The Hurd is a collection of servers that run on top of a microkernel (such as Mach) to implement different features. The Hurd is free software produced by the GNU project.
A large part of the basic tools that fill out the operating system come from the GNU project; hence the names: GNU/Linux and GNU/Hurd. These tools are also free.
Of course, the thing that people want is application software: programs to help them get what they want to do done, from editing documents to running a business to playing games to writing more software. Debian comes with over 29000 packages (precompiled software that is bundled up in a nice format for easy installation on your machine) — all of it free.
It's a bit like a tower. At the base is the kernel. On top of that are all the basic tools. Next is all the software that you run on the computer. At the top of the tower is Debian — carefully organizing and fitting everything so it all works together.
It's all free?
You may be wondering: why would people spend hours of their own time to write software, carefully package it, and then give it all away? The answers are as varied as the people who contribute. Some people like to help others. Many write programs to learn more about computers. More and more people are looking for ways to avoid the inflated price of software. A growing crowd contribute as a thank you for all the great free software they've received from others. Many in academia create free software to help get the results of their research into wider use. Businesses help maintain free software so they can have a say in how it develops -- there's no quicker way to get a new feature than to implement it yourself! Of course, a lot of us just find it great fun.
Debian is so committed to free software that we thought it would be useful if that commitment was formalized in a written document. Thus, our Social Contract was born.
Although Debian believes in free software, there are cases where people want or need to put non-free software on their machine. Whenever possible Debian will support this. There are even a growing number of packages whose sole job is to install non-free software into a Debian system.
The Debian project is pleased to announce the sixth update of its stable distribution Debian 6.0 (codename squeeze). This update mainly adds corrections for security problems to the stable release, along with a few adjustments for serious problems. Security advisories were already published separately and are referenced where available.
Please note that this update does not constitute a new version of Debian 6.0 but only updates some of the packages included. There is no need to throw away 6.0 CDs or DVDs but only to update via an up-to-date Debian mirror after an installation, to cause any out of date packages to be updated.
Those who frequently install updates from security.debian.org won't have to update many packages and most updates from security.debian.org are included in this update.
New installation media and CD and DVD images containing updated packages will be available soon at the regular locations.
Upgrading to this revision online is usually done by pointing the aptitude (or apt) package tool (see the sources.list(5) manual page) to one of Debian's many FTP or HTTP mirrors. A comprehensive list of mirrors is available at: http://www.debian.org/mirror/list