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, you have a Gentoo installation, not a Gentoo 2005.1 or 2004.3 installation. Therefore you will continue to benefit from the Gentoo development with every system update you perform - there is no need to run through a specific upgrade procedure every time Gentoo makes a new release.

Yes, Gentoo does release often - twice a year to be exact. Such a release brings you an up to date LiveDVD with the latest hardware drivers and features that might improve your installation experience.

When you hear someone talk about a specific Gentoo release (Gentoo 12.1 for instance) they are talking about this LiveDVD, not about the state Gentoo is at at a certain point in time. Gentoo evolves on a daily basis (there are changes every few minutes!), but can't develop, package, test and release new installation CDs every time a change within Gentoo occurs...

Gentoo release media
By default, Gentoo releases LiveDVDs: DVDs allowing you to immediately boot in a Gentoo Linux environment containing the necessary tools to help you install Gentoo on your system, but also try out Gentoo without the need to install it on your system.

Next to the bi-yearly LiveDVD releases, Gentoo also offers installation media. These are small, bootable CD images (often referred to as the minimal CDs) which allow you to boot up into an environment suitable to start the installation of Gentoo Linux.

These bootable CD images are generated every few weeks. Gentoo has automated the build and testing process for the release of these installation CDs so users will always have an up-to-date installation experience.

Introduction
You should understand that the Gentoo installation procedure - at least the officially published one - 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 lot of 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.

Another 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.

Stage-based installation
A standard Gentoo Linux installation starts from a minimal Gentoo environment, containing the core system utils that anyone would need to get Gentoo up and running. This is the preferred initial state for most users and also the fastest way to install Gentoo. From this state onward, the user installs the additional tools he requires (such as certain networking tools for automated IP information retrieval, cron jobs for scheduled process execution, system logger for keeping track of all log events, ...) and builds a Linux kernel to boot from.

This is done by extracting a small Gentoo environment (called the stage or stage3 file) onto the users' system and then performing the finishing touches within this small environment.

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 thatthe system is waiting for further input:

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