GENTOO LINUX

The 'Gentoo Linux' operating system (pronounced ) is a Linux distribution named after the Gentoo penguin. It is designed to be modular, portable, easy to maintain, flexible, and optimized for the user's machine. All tools and utilities are built from source code. For convenience, however, several large software packages are also available as precompiled binaries for various architectures via the Portage system.

Contents

History

Portability

Portage

Init system

Installation

Catalyst

Stages

Version history

Criticism

Logo and mascots

Gentoo-based distributions

See also

References

External links

Official

Community

Press

Miscellaneous

Security vulnerabilities

History

Gentoo was initially created by Daniel Robbins as the ''Enoch Linux'' distribution. The goal was to create a distribution that was built from source code, tuned to the hardware, only included required programs, and decreased maintainer workload through scripting.^[1] At least one version of Enoch was distributed: version 0.75, in December 1999.^[2]
Compilation issues revealed problems with the GNU Compiler Collection (gcc), used to build from source code. Daniel Robbins and the other contributors experimented with "forked" versions of gcc, finding a version that gave a 10% to 200% speed increase over the "official" gcc. At this point, Enoch gained a reputation for its speed, prompting the name change to Gentoo Linux (the Gentoo species is the fastest swimming penguin). The modifications eventually became part of the official gcc (version 2.95), and other Linux distributions experienced similar speed increases.^[3]
After problems with a bug on his own system Robbins halted Gentoo Linux development and switched to FreeBSD for several months, later saying "I decided to add several FreeBSD features to make our autobuild system (now called Portage) a true next-generation ports system."^[4]
Gentoo Linux 1.0 was released 2002-03-31.^[5]
Robbins had wanted Gentoo Linux to become a commercially successful project, but found an appropriate business model difficult to achieve. In 2004 he set up the non-profit Gentoo Foundation and transferred all copyrights and trademarks to it and stepped down as Chief Architect of the project; he later worked at Microsoft's Linux Lab for almost two years.^[6][7]
The current board of 5 trustees was elected on October 21, 2006. There is also a subsidiary 7 member Gentoo Council whose members "decide on global issues and policies". The current Council members were elected September 11, 2006 by 121 active Gentoo developers.

Portability

Although originally designed for the x86 architecture, it has been ported to many others and currently runs on the x86, x86-64, IA-64, PA-RISC; PowerPC, PowerPC 970, SPARC, MIPS, DEC Alpha, ARM, zSeries/s390, and SuperH architectures.^[8] Gentoo was the first distribution to offer a fully functional 64-bit Linux computing environment (user space and the kernel) for the PowerPC 970.
There is also a "Gentoo for Mac OS X" project which allows Mac OS X users to use Gentoo's Portage to install packages, in a similar way to the one provided by Fink. Although still a work in progress, this project can coexist with Fink because it uses the same environment as Mac OS X instead of creating a new one.
Portability toward other operating systems, such as BSD-derived ones, is under active development by the Gentoo/ALT project. The Gentoo/FreeBSD project already has a working release, while Gentoo/NetBSD, Gentoo/OpenBSD and Gentoo/DragonFly are being developed. There is also a project to get Portage working on the GNU Hurd although development is slow.

Portage

Main articles: Portage (software)

Portage is Gentoo's default package management system. It is similar in idea to the BSD ports collections: the original design was based on FreeBSD ports. Portage is written in Python and is the main utility that defines Gentoo from other Linux distributions. It consists of two main parts, the ''ebuild'' system and ''emerge''. The ebuild system takes care of building and installing packages and emerge is a frontend that performs dependency resolution, executes ebuilds and tracks installed software.

Init system

Gentoo's init system is another important feature of its system. It is similar to the System V init system that most Linux distributions use, but uses dependency based scripts and named run levels rather than numbered ones. It also includes a command called ''rc-update'' which manages runlevels.
A faster init system known as initng is available and under active development on the Gentoo forums.
A new baselayout, baselayout-2, version is nearing completion, that moves core system scripts from bash scripting to C code. This change should make boot time and other lower level services faster^[9].

Installation

Gentoo may be installed in several ways. The most common way is to use the Gentoo LiveCDs. As with many Linux distributions, it can also be installed by most LiveCDs and existing Linux installations.
Installation of Gentoo can be completed by following the Gentoo Handbook. Additionally, several other methods of installation are listed in the Alternative Installation Method HOWTO; most of which are targeted at experienced users or users unable to boot from the Gentoo live CD.
As of version 2006.0, the Gentoo Foundation has released a GTK+ based installer to greatly simplify the process of installing the distribution from scratch.[1] More advanced users will note that the new installer also brings back the stage 1 installation (see below) as a common installation method.

Catalyst

Starting with 2004.0, Gentoo introduced a tool called Catalyst, which is used to build all Gentoo releases and can be used to build one's own customized install media.

Stages

Traditionally installation could be started from one of three base stages:

★ Stage1: System must be bootstrapped and the base system must be compiled.

★ Stage2: System has already been bootstrapped, but the base system must be compiled.

★ Stage3: System has already been bootstrapped and the base system already compiled.
As of November 2005, only stage3 installations are officially supported. Although tarballs for stage1 and stage2 are still distributed, the instructions for installing from these stages have been removed from the handbook and put into the Gentoo FAQ.

Version history

★ 1.0, March 31, 2002

★ 1.2, June 2002

★ 1.4 August 5, 2003 (Gentoo Reference Platform introduced)

★ 1.4 maintenance release 1 September 11, 2003

★ 2004.0 March 1, 2004 (versioning changed to four releases a year)

★ 2004.1 April 28, 2004

★ 2004.2 July 26, 2004

★ 2004.3 November 15, 2004

★ 2005.0 March 27, 2005 (versioning changed to semi-annual releases)

★ 2005.1 August 8, 2005

★ 2005.1 maintenance release 1 November 21, 2005

★ 2006.0 February 27, 2006

★ 2006.1 August 30, 2006

★ 2007.0 May 7, 2007
Even though the versioning system changed to years, the numbering version system still continues. For example, /etc/gentoo-release might contain "Gentoo Base System version 1.6.13" (Modified Aug. 26, 2005). These numbers are actually the version numbers of the sys-apps/baselayout package in Portage.
Once Gentoo is installed, it becomes "versionless"; that is, once an ''emerge'' update is done, the system is at the latest version. If the system was installed from a 2005.0 CD and 2005.1 was released, an ''emerge'' update of the system effectively makes the installed 2005.0 system equivalent to the newly released 2005.1 installation.

Criticism

Gentoo has attracted criticism in a number of areas.
; Slow package installation : Compiling from source means that packages are slower to install. Slow package installation leads to a longer initial installation if a lot packages are installed. In the extreme cases of KDE and OpenOffice.org, package installation will take hours, or even days on older hardware. Also compiling these packages requires a lot of hard disk space (4–6 GB for OpenOffice.org – see app-office/openoffice ebuild for more information). Generally, Gentoo users accept these delays as the cost of being able to apply their own compile-time options, but there are now pre-compiled binaries for large popular applications such as KDE, OpenOffice.org, and Mozilla Firefox. Using these binaries one loses the chance to customize the packages, but the installation of the package is reduced to a few minutes.
; Package manager does not handle reverse dependencies : When removing a package, Portage does not check to see if any other installed packages still need it. Portage also does not check if upgrading a particular package would have a "ripple effect" on any other installed packages. Therefore it's possible to cause an installed application to malfunction by removing or upgrading another package it depends on. This can lead to users unknowingly breaking their systems by careless removal of packages, or upgrading a library to an incompatible version. For upgrades, there exists a 'revdep-rebuild' utility (contained in the package 'gentoolkit') that scans the entire system and looks for packages that require a rebuild. This must be installed and run manually by the user. Unused reverse dependencies can be located and removed using emerge --depclean. This command analyzes the entire list of installed packages against the dependency tree of required packages and removes any packages no longer required. The dependency tree of required packages is defined by the list of packages installed by the user as recorded in /var/lib/portage/world. Unfortunately, it still does not consider packages which are dynamically linked. 'revdep-rebuild' should be used to resolve this issue as well. --depclean should only be run after a successful sync and deep update of world to make sure the defined dependency tree is accurate.
; Requires a good Internet connection : This seems to be related to downloading sources prior to building packages. However, any other distribution that has internet updates has to download binary packages instead, and the sizes of binary and source packages are usually comparable. In an effort to ease this requirement, the necessary files can be pre-fetched with the emerge -f or --fetchonly flag, or they can be downloaded in the background while compiling by enabling the parallel-fetch feature.

Logo and mascots

The official Gentoo logo is the stylized G resembling a silver magatama.
Unofficial mascots include Larry the cow and Knurt the flying saucer.
In fact as Larry appeared originally on the official website, it can be considered semi-official. However, there is much controversy around Larry, laid out in several heated debates on the Gentoo forums, mainly because of his/her gender ambiguity.

Gentoo-based distributions

★ Bintoo

★ Flash Linux on USB key

★ Gentoox

★ Knopperdisk

★ Kororaa

★ Librix

★ Litrix

★ Navyn OS

★ Pentoo

★ SabayonLinux

★ SystemRescueCD

★ Ututo

★ VidaLinux

★ Phaeronix

See also

★ Gentoo/Alt

References

1. http://www.gentoo.org/doc/en/articles/making-the-distro-p1.xml
2. http://public.planetmirror.com/pub/enoch/enoch-0.75
3. http://www.gentoo.org/doc/en/articles/making-the-distro-p2.xml
4. http://www.gentoo.org/doc/en/articles/making-the-distro-p3.xml
5. http://linux.slashdot.org/article.pl?sid=02/03/31/2123251
6. http://slashdot.org/article.pl?sid=04/04/26/2259211
7. http://linux.slashdot.org/article.pl?sid=05/06/13/2137239
8. http://www.gentoo.org/proj/en/releng/release/2007.0/2007.0-press-release.txt
9. http://www.gentoo.org/news/en/gwn/20070416-newsletter.xml

External links

Official

★ Gentoo website

★ Embedded Gentoo (Official Embedded Site)

Community

★ Gentoo Wiki

★ Gentoo Community Portal (was larrythecow.com) - a large directory of Gentoo related websites (dead link as of 30-Apr-07).

★ Gentoo Community News (was larrythecow.net) - a news site similar to slashdot featuring Gentoo related articles.(dead link as of 30-Apr-07).

★ Planet Larry - an aggregation of Gentoo user blogs

★ Gentoo-Portage - An online searchable version of the portage tree.

★ Quickstart install - Quick and dirty install guide.

★ Embedded Gentoo How To for x86 - x86 Embedded How-to

★ PFL - Portage File List - search for files in packets

★ PFS - Portage File Search - search for files in packets

Press

★ E-Trade VP Talks Open Source January 26, 2006, eweek.com (Pages 3-5) E
★ Trade's Vice President of Architecture Lee Thompson talks about how he uses Gentoo.

Miscellaneous

★

Security vulnerabilities

★ Secunia advisories for Gentoo (including patched and unpatched vulnerabilities)

★ Gentoo Linux Security Advisories