User:SwifT/Complete Handbook/Versions media installation concerns

Gentoo versions
One of Gentoo's major advantages is that it does not really know versions. Once installed, the user has a Gentoo installation, not a Gentoo 2005.1 or 2004.3 installation. Therefore users will continue to benefit from the Gentoo development with every system update performed - there is no need to run through a specific upgrade procedure every time Gentoo makes a new release.

This is also reflected by the pace at which Gentoo provides new installation media: through an auto-build process, new media are provided on a weekly basis (for active architectures). These auto-builds contain all the necessary media to install Gentoo with, and is also the medium that we will use throughout this handbook.

Gentoo LiveDVD releases
Occasionally, Gentoo will create a Gentoo LiveDVD from which one can play with a Gentoo OS before installing it. These releases are announced on the main Gentoo website.

How a Gentoo installation is done
You should understand that the Gentoo installation procedure is quite different from most other Linux distributions: where other distributions try to perform most steps for you, Gentoo Linux asks you politely (but firmly) to do things yourself.

Getting the hardware up and running, configuring the network, partitioning your disk(s), copying over the initial files, building additional software (including the kernel), ... all these steps should be performed before you can finally boot in a minimal Gentoo environment. Not that all these steps can't be automated (Gentoo even offers tools to automate a few of those steps and you'll find a few unofficial installers that automate most - if not all - steps) but by documenting these steps in great detail Gentoo almost forces you to learn various Linux-related procedures.

The structure of a Gentoo installation is as follows:


 * 1) Download and boot a bootable system from which Gentoo can be installed
 * 2) Prepare your disk(s) and partitions to host Gentoo
 * 3) Download and extract the latest archive (stage file) which creates a minimal Gentoo environment to further install from
 * 4) Chroot into this minimal Gentoo environment and install a Linux kernel, core utilities and boot loader
 * 5) Reboot into the freshly installed Gentoo system

A huge advantage of letting the user perform all steps himself is that the user can now decide himself how he wants to install Gentoo - the options are there, the user needs to make a choice, over and over again. By clearly identifying the options and documenting the possible roads Gentoo hopes that the user is not scared but rather impressed.

Download, burn and boot
In order to boot a medium from which Gentoo can be installed, the first thing to know is for which architecture the installation should be done.

Gentoo supports a number of architectures, namely:

The majority of Gentoo users use the x86_64 architecture (AMD64).

Download the media
With the information handed to you in the previous sections you should have an idea what CD(s) you need to download. Gentoo provides the CDs as an FTP/HTTP download. Pick the latest version available (as that one contains the most up-to-date hardware support and additional features) although this is not mandatory: you can easily install a (current) Gentoo from an older installation CD.

As the directory structure on the FTP/HTTP mirrors suggests, you'll find the CDs in the directory.

Each CD is fully contained within an ISO file. Such a file contains all the content of a CD and should be burned on the CD using a specific (but well supported) procedure. Most CD/DVD burning tools call it Burn ISO or Raw burning; it differs from the regular burning methods used that it burns the content of the file on the CD, not the file as-is (i.e. the end result is not that you just see the single file on the burnt CD).

If you want, you can verify the downloaded ISO file using the file we provide. This file contains a SHA-2 and Whirlpool checksum of the file, a known mathematical result of the entire CD that is practically unique to every file. In other words, you won't (easily) find a file anywhere with the same checksum unless that file is identical. Under Linux, you can use the sha512sum and openssl dgst -whirlpool tools to verify the checksum.

We also provide a digital signature of the file made with our private Release Engineering key. This digital signature can be used to validate the origin of the ISO file: if the digital signature matches the public key of the Release Engineering team, then the file is authentic. Under Linux, you can use the gpg tool to verify the checksum.

Booting the CD
To get in the initial Gentoo environment, you need to boot from the installation CD. How to achieve this depends on the architecture you are using. The first appendix in this book covers the various architecture-specific aspects of a Linux system, including booting CDs.

Once booted, you will see that the installation CD already tried to load the necessary drivers and hands you over to a root prompt, indicating that the system is waiting for further input:

This is the command-line prompt. You are now booted in the initial Gentoo environment, ready to continue.