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Gentoo Linux

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The Gentoo logo

Template:Infobox OS Gentoo Linux is a Linux distribution named after the Gentoo Penguin. It is designed to be modular, portable and optimized for the user's machine. This is accomplished by building all tools and utilities from source code, although, for convenience, several large software packages are also available as precompiled binaries for various architectures. Gentoo achieves all this via the Portage system. Gentoo is also appreciated for its discussion forums and the large knowledge base they represent.

Contents

Portage

Portage is similar to the *BSD package management system called ports; in fact it was originally designed with FreeBSD's ports in mind. Gentoo's Portage system works similarly to Debian's APT. Portage is written in the Python programming language, and is the main utility that defines Gentoo. Although the system itself is known as Portage, its features are actually invoked on the command line with the program 'emerge'.

USE flags

The Portage system offers the use of "USE flags," which allows users to indicate which software features they would like to include while building packages. For example, there is a USE flag to include DVD support, where available, in all packages that are compiled after the flag is enabled. The USE flags can affect which dependencies are built or what options are sent to the program when it is compiled. The specification of USE flags is the usual way to configure programs on Gentoo.

Ebuilds

Gentoo does not use binary packages as package management systems like RPM, instead employing a format known as the ebuild. The main difference between RPM files and ebuilds is that RPMs are precompiled binaries, whereas ebuilds are text files which contain a description of the software, and instructions on how to obtain, configure, compile, and install it. There are nearly nine-thousand-five-hundred ebuilds available; the majority of which are distributed by the Gentoo mirrors. New and updated ebuilds can be obtained by synchronizing the local ebuild repository with the mirrors. This is done by executing the command emerge --sync.

Masking

Masking is how Gentoo determines which packages are suitable for a system. Ebuilds designed for different architectures or experimental software are usually masked in a way that will not allow a stable system to install them without proper user intervention, as adding a package name to /etc/portage/package.keywords. Experimental packages are hard masked. Installing hard masked ebuilds is considered risky, and is generally not recommended because they have known problems.

Packages that are masked by keyword (i.e. they are available for systems with the a testing keyword commencing with ~, such as ~x86, ~amd64, ~ppc) generally just need some testing, but will often work fine.

The standard way to unmask a hard masked package is to copy its entry from /usr/portage/profiles/package.mask into /etc/portage/package.unmask.

Installation

Gentoo may be installed in several ways. The most common way to install it is by using the Gentoo Live CD, but it can also be installed by most other Linux Live CDs, and even from an existing Linux installation on another partition of the same hard drive. The machine must be prepared for installation by partitioning the hard disk and installing a base system corresponding to one of three stages. Starting from the first stage allows for the most customization and optimization, starting from the third stage allows for a quicker installation and starting from the second stage is a happy medium between the two.

Installation is done in a chroot environment where Gentoo's own Portage system is used to install critical packages for the new installation. Gentoo does not feature an installation program as in many other distributions (though one is under development); the user follows the steps described in the Gentoo Handbook (http://www.gentoo.org/doc/en/handbook/index.xml) available on the Gentoo website and Live CD.

Stages

  • Stage 1, Full Installation, where the system must be bootstrapped and the base system must be compiled.
  • Stage 2, System has already been bootstrapped, but the base system must be compiled.
  • Stage 3, System has already been bootstrapped and the base system already compiled.

One of the three stages is chosen as a tradeoff between customizability and install time. The default compiler in Gentoo is GCC. Compiler customizations are made in an environment variable called CFLAGS. The system then must be bootstrapped, which is done by compiling the compiler and base libraries.

Other packages

After the three stages, the system configuration must be written. Then, the user is free to install what they want; they can download binary packages from the Gentoo Reference Platform, as well as compile their own software.

Kernel

The kernel must also be set up and installed during installation. Gentoo does not have a precompiled kernel; instead it offers various kernel sources, many with enhancement patches. Configuration can either be done by the traditional menuconfig utility included with Linux or with genkernel, an all-purpose kernel compilation program.

System configuration

After the kernel is installed, the system configuration files must be edited manually to fit the needs of the user. This includes the fstab, network configuration, and system customizations. Most important is the Gentoo-specific make.conf file in /etc/. It contains settings that control the compilation of the packages and is generally updated by the system administrator when the values need to be changed from their defaults. The make.conf file contains environment variables like CFLAGS, CHOST, USE, ACCEPT_KEYWORDS and many others. Review the make.conf manpage for a complete list of variables.

Boot loader

Once the kernel is installed, the bootloader must be installed so that the system can be loaded without the use of external bootable media. The most popular Gentoo bootloader is GRUB, although some users prefer the older LILO.

System utilities

Although not necessary for a functional Gentoo installation, a few packages separate from the base system are highly recommended: a system logger, filesystem tools, and a cron daemon. Gentoo provides several options for each tool, which the user can select based on their preferences and needs.

Finalizing installation

The final part of the installation involves creating user accounts and installing any precompiled packages the user wants. After this, the user can reboot the system. The system is now a functional standalone and no longer requires the live CD.

Install utilities

Catalyst

Starting with version 2004.0, Gentoo introduced a tool called Catalyst (http://www.gentoo.org/proj/en/releng/catalyst/), which is used to build all Gentoo releases and can be used to build one's own customized install media.

Tarballs

It is possible to create tarballs of packages for distribution to other machines. These binary packages, with a .tbz2 extension, consist of all files installed by the package and a metadata section that makes it possible to install them by using the -k or -K options to emerge. This is particularly useful in the case of a homogeneous computing environment, where packages may be used on many machines despite having been prepared on a specific one. Additionally, because they can be installed directly to the filesystem root without using Portage, they can be extremely useful for rescuing a broken system.

Portability

Gentoo was originally designed solely for the x86 architecture, but it has been ported to many others due to the highly-portable nature of Linux, gcc, glibc and Portage. It currently runs on the x86, PowerPC, PowerPC 970, SPARC, AMD64, IA64, MIPS, DEC Alpha, HP/PA, ARM, and zSeries/s390 architectures. Gentoo was the first distribution to offer a fully functional 64bit Linux computing environment (user space and the kernel) for the PowerPC 970 architecture.

There's 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 without having to rely on a chroot environment). Although still a work in progress, this project can replace Fink because it uses the same environment as Mac OS X instead of creating a new one.

Also, projects to make Portage work on OpenBSD, FreeBSD and Sega Dreamcast are at an initial stage.

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 used, but it uses named run levels rather than numbered ones, and dependency based scripts. It also includes a command called rc-update which manages runlevels.

Versions

Version 1.0 was the first major version of Gentoo. It was released 31 March 2002.

Version 1.2 was the second, released in June 2002.

In Gentoo Linux 1.4, the Gentoo Reference Platform (GRP) was introduced. It provides precompiled packages, and when combined with a stage 3, a user can have a fully working Gentoo system without the previous long install time.

In 2004, the versioning scheme changed to being year-based in the form of Year.Revision. For example, 2004.0 would be the first release of Gentoo in 2004 while 2005.3 would be the fourth revision of Gentoo in 2005.

The latest official version of Gentoo is Gentoo 2005.0. For more information, see the official Information Guide (http://www.gentoo.org/proj/en/releng/release/2005.0/2005.0.xml).

The portage system, however, allows the installed components of the system to be upgraded as needed to the newest version, thus negating the need to re-install the system when a new version is released.

History

8 June 2005 Voting (http://article.gmane.org/gmane.linux.gentoo.devel/28603) to change the Metastructure of the Gentoo Developer team is opened.

  • The FOSDEM (http://dev.gentoo.org/~plate/fosdem-proposal.xml) proposal
  • Koon's Alternative (http://dev.gentoo.org/~koon/metastructure.xml) proposal
  • G2boojum's Oldschool-small (http://dev.gentoo.org/~g2boojum/proposal.html) proposal with a small council (7-13 members)
  • G2boojum's Oldschool-large (http://dev.gentoo.org/~g2boojum/proposal.html) proposal with a large council (such as 0.1*Ndevs + (Ndevs+1)%2 members)
  • Ciaranm's Oldschool-small-with-slacker-boot (http://dev.gentoo.org/~spb/ciaranm-slacker-boot-proposal.txt) http://dev.gentoo.org/~g2boojum/proposal.html with a small council (7-13 members)
  • Ciaranm's Oldschool-large-with-slacker-boot (http://dev.gentoo.org/~g2boojum/proposal.html) with a large council (http://dev.gentoo.org/~spb/ciaranm-slacker-boot-proposal.txt) (such as 0.1*Ndevs + (Ndevs+1)%2 members)
  • Keep the current system ("Keep-current"). See: Gentoo Projects (http://www.gentoo.org/proj/en/index.xml) and Developers Handbook (http://www.gentoo.org/proj/en/devrel/handbook/handbook.xml?part=1&chap=5)


The four election officials are:

  • Aron Griffis (agriffis)
  • Grant Goodyear (g2boojum)
  • Thierry Carrez (koon)
  • Olivier Crete (tester)


25 May 2005 The first board of trustees has been elected. (http://www.gentoo.org/foundation/en/)

1 May 2005 The Gentoo Store (http://www.gentoo.org/foundation/en/funds.xml#doc_chap2) is now run by the Gentoo Foundation as a CafePress store. Portions of profit support the development of Gentoo. This is the Official way to buy installation media, T-shirts, and other Gentoo branded merchandise.

The store used to be run by Daniel Robbins, the founder of Gentoo Linux.

26 April 2004, Daniel Robbins, founder of Gentoo Linux, stepped down as Chief Architect of the project. Before leaving, he set up a non-profit foundation, known as the Gentoo Foundation, and transferred all the copyrights to it. The initial board of trustees was appointed by Robbins and elections were scheduled for the following year. The membership of the foundation was initially set to be open. Upon his resignation, an article (http://slashdot.org/article.pl?sid=04/04/26/2259211) was posted to Slashdot.

Gentoo Linux Website

The Gentoo Foundation held a contest for a redesign of the Gentoo website in July 2004. Aaron Shi's design won the contest which was voted upon by the Gentoo community. [1] (http://www.gentoo.org/proj/en/infrastructure/redesign-guidelines.xml)

Update - May 1 2005 M Curtis Napier (curtis119) has begun the process of converting the winning design to the gentoo XSL/GuideXML format. As part of the process the entire XSL/XML infrastructure is being audited and documented.

Criticisms of the Gentoo Linux Distribution

Gentoo is sometimes criticized for poor QA (though possibly this is an unavoidable consequence of focusing on having more "up-to-date" versions of software available), unstable "stable" branches and for having a closed "upper management elite".

Many of the difficulties experienced in past years from the "stable" branch have dissipated due to the addition of a separate "unstable" branch, and will most likely continue to improve with time and effort. However, Gentoo, having a bleeding edge repository of software, often relies on the "upstream"'s (i.e. original authors) QA process. This works well for highly-used software (such as Apache), but less so for little-used software.

Gentoo is also criticised for its long installation process, usually taking days on older hardware. One of the other interesting debates commonly held is the binary versus source packaging, Gentoo using the latter by default. Source packagers claim that binaries are slower and less customizable, while binary packagers retort that some packages take days to compile and are incompatible with the needs of many users who require quick software installation. Furthermore, some compile-time customizations might make packages less stable. Both systems have advantages and disadvantages.

In response to this criticism, Gentoo began offering precompiled binaries for various architectures of popular applications including KDE, GNOME, OpenOffice.org, Mozilla, Mozilla Firefox and others, and all the packages required to run them. These sets of packages are referred to as the Gentoo Reference Platform (GRP) and are updated with every new release of Gentoo.

Finally, the closed "upper management elite" accusation has dissipated since Daniel Robbins formed the Not For Profit organization known as the Gentoo Foundation. These criticisms are hotly debated between a vocal minority of users of community-based Linux Distributions.

Gentoo has been seen by some as an adversary of Debian. In particular, some Gentoo users have claimed they turned to Gentoo from Debian because of the helpfulness of fellow users in the Gentoo forums, compared to the harsher treatment reserved to new users in Debian mailing lists (see also RTFM).

Logo & Mascot

The official Gentoo logo is the stylized G (http://img166.exs.cx/img166/8973/gentoog27px.png). Unofficial mascots include Larry the cow (http://www.gentoo.org/main/en/about.xml) and the UFO guy (http://img167.exs.cx/img167/1043/gentooufo2qx.gif).

See also

External links

ca:Gentoo cs:Gentoo de:Gentoo Linux et:Gentoo es:Gentoo Linux eu:Gentoo fr:Gentoo id:Gentoo Linux it:Gentoo he:ג'נטו לינוקס hu:Gentoo nl:Gentoo Linux ja:Gentoo Linux no:Gentoo pl:Gentoo Linux pt:Gentoo Linux ru:Gentoo sk:Gentoo fi:Gentoo Linux sv:Gentoo Linux tr:Gentoo zh:Gentoo Linux

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