Gentoo Linux is a computer operating system built on top of the Linux kernel and based on the Portage package management system. It is distributed as free and open source software. Unlike a conventional software distribution, the user compiles the source code locally according to their chosen configuration.
There are normally no precompiled binaries for software, continuing the tradition of the ports collection, although for convenience, some software packages are also available as precompiled binaries for various architectures.
The development project and its products are named after the Gentoo penguin. Gentoo package management is designed to be modular, portable, easy to maintain, flexible, and optimized for the user’s machine. Gentoo describes itself as a metadistribution, “because of its near-unlimited adaptability”.
Here is some history and other information.
Gentoo Linux was initially created by Daniel Robbins as the Enoch Linux distribution. The goal was to create a distribution without precompiled binaries that was tuned to the hardware and only included required programs. At least one version of Enoch was distributed: version 0.75, in December 1999.
Compilation issues revealed problems with the GNU Compiler Collection (GCC), used to build from source code. Daniel Robbins and the other contributors experimented with a fork of GCC known as EGCS developed by Cygnus Solutions. At this point, Enoch changed name to Gentoo Linux (the Gentoo species is the fastest swimming penguin). The modifications to ECGS eventually became part of the official GCC (version 2.95), and other Linux distributions experienced similar speed increases.
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.”
Gentoo Linux 1.0 was released March 31, 2002. In 2004, Robbins set up the non-profit Gentoo Foundation, transferred all copyrights and trademarks to it, and stepped down as Chief Architect of the project.
The current Board of Trustees is composed of five members who were announced (following an election) on March 2, 2008. There is also a seven-member Gentoo Council that oversees the technical issues and policies of Gentoo. The Gentoo Council members are elected for a period of one year, each year by the active Gentoo developers. When a member of the Council retires, the next in line person is voted into place by the existing Council members.
The Gentoo Foundation is a 501(c)(6) non-profit foundation, registered in the State of New Mexico. In late 2007, the Foundation’s charter was revoked. As of May 19, 2008, the State of New Mexico declared that the Gentoo Foundation, Inc. has returned to good standing and is free to do business. Portability
Although originally designed for the x86 architecture, it has been ported to many others. Currently it is officially supported and considered stable on x86, x86-64, IA-64, PA-RISC, PowerPC, PowerPC 970, SPARC 64-bit and DEC Alpha architectures. It is also officially supported but considered in development state on MIPS, PS3 Cell Processor, System Z/s390, ARM, and SuperH. Official support for 32-bit SPARC hardware has been dropped.
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 guide based on FreeSBIE, while Gentoo/NetBSD, Gentoo/OpenBSD and Gentoo/DragonFly are being developed. There is also a project to get Portage working on OpenSolaris. There was an unofficial project to create a Gentoo port to GNU Hurd but it has been inactive since 2006 Portage Main article: Portage (software)
Portage is Gentoo’s package management system. It is similar in idea to the BSD ports collections: the original design was based on FreeBSD ports. In contrast, the Portage tree does not contain directories of Makefiles, but of so-called ebuilds, bash scripts that describe separate functions to download, configure, make, install and remove a package and additional functions that can be used to set up the operating environment for a package.
Portage’s main utility is emerge, which is written in Python and can be used by privileged users to easily inspect and alter the set of installed packages on a Gentoo operating system. Whereas emerge used to operate in a similar way to other ports collections, by entering a directory in the tree and using emerge (instead of make) to perform package management operations, it now reads variables from the file /etc/make.conf (again similar to ports) to determine where the Portage tree is kept.
Alternative package management utilities like Paludis and pkgcore have seen heavy development. Both are intended to be used alongside or instead of the official Portage utilities in both development and practical use. As both competing projects intend to replace the official utilities, an effort has been raised to standardise the application programming interface (API) of ebuilds for all package managers, in a project called the Package Manager Specification or PMS. Init system
Gentoo’s init system is another important feature. 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.
Gentoo startup scripts use the runscript shell interpreter, rather than a more traditional shell.
Originally Gentoo’s rc system was written entirely in bash and was part of the baselayout package, which contains the basic filesystem layout and critical files needed for the system. However, this led to several limitations. For example, certain system calls needed to be accessed during boot which required C-based callouts to be added. These callouts were each statically linked, causing the rc system to bloat over time. Additionally, as Gentoo expanded to other platforms such as Gentoo/FreeBSD and Gentoo Embedded, requiring the relatively heavy bash shell for the rc system became undesirable or sometimes impossible.
This led to a development of baselayout 2, which was written in C and only required a POSIX-compliant shell. During this development, it was decided that it was a better fit if baselayout provided only the base files and filesystem layout for Gentoo, and the rc system was broken off into an independent project – OpenRC. Installation
Gentoo may be installed in several ways. The most common way is to use the Gentoo minimal CD with a stage 3 tarball (see below for more explanation on stages). As with many Linux distributions, it can also be installed by most Linux flavors already operating.
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. More advanced users will note that the new installer also brings back the stage 1 installation (see below) as a common installation method.
Unusually amongst Linux distributions, an early and mandatory step in the installation process is compilation of the kernel. Widely regarded as a complex task, Gentoo provides documentation and tools such as Genkernel to simplify the process and make it straightforward for novice users. 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. In summer 2008, Daniel Robbins Gentoo’s founder released a new build tool called metro. metro is used to build releases of funtoo, a slight variant of gentoo, developed and maintained by Daniel Robbins. metro hasn’t been integrated in gentoo release process though. 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.
I’ve only tried Gentoo once. The installation can be a P#$%n in the @$$, but when its installed its one of the fastest distributions. Gentoo is completely compiled from scratch when installed, and highly customized for the host computer. So if you do have a lot of Linux experience, try it out!!
Gentoo is not for you if you don’t like to compile stuff on your own and if you’re not willing to get your hands dirty!