Source model Open source | Working state Current | |
Developer Aaron Griffin and others Initial release March 11, 2002; 14 years ago (2002-03-11) Latest release Rolling release / installation medium 2017.02.01 | ||
Arch Linux (or Arch /ˈɑːrtʃ/) is a Linux distribution for computers based on i686 and x86-64 architectures. It is composed predominantly of free and open-source software, and supports community involvement.
Contents
- History
- Repository security
- Design and principles
- Installation
- Pacman
- Repositories
- Arch Build System ABS
- Arch User Repository AUR
- Derivatives
- Rolling releases
- Other platforms
- References
The design approach of the development team follows the KISS principle ("keep it simple, stupid") as the general guideline, and focuses on elegance, code correctness, minimalism and simplicity, and expects the user to be willing to make some effort to understand the system's operation. A package manager written specifically for Arch Linux, pacman, is used to install, remove and update software packages.
Arch Linux uses a rolling release model, such that a regular system update is all that is needed to obtain the latest Arch software; the installation images released by the Arch team are simply up-to-date snapshots of the main system components.
Arch Linux has comprehensive documentation in the form of a community wiki, called the ArchWiki.
History
Inspired by CRUX, another minimalist distribution, Judd Vinet started Arch Linux in March 2002. Vinet led Arch Linux until 1 October 2007, when he stepped down due to lack of time, transferring control of the project to Aaron Griffin.
Originally only for 32-bit x86 CPUs, the first x86_64 installation ISO was released in 2006. The end of i686 support was announced in January 2017, with the February 2017 ISO being the last one including i686, and finally making the architecture unsupported in November 2017.
Repository security
Until pacman version 4.0.0 Arch Linux's package manager lacked support for signed packages. Packages and metadata were not verified for authenticity by pacman during the download-install process. Without package authentication checking, tampered-with or malicious repository mirrors can compromise the integrity of a system. Pacman 4 allowed verification of the package database and packages, but it was disabled by default. In November 2011 package signing became mandatory for new package builds, and as of 21 March 2012 every official package is signed.
In June 2012, package signing verification became official and is now enabled by default in the installation process.
Design and principles
Arch is largely based around binary packages. Packages are targeted for IA-32 and x86-64 microprocessors to assist performance on modern hardware. A ports/ebuild-like system is also provided for automated source compilation, known as the Arch Build System.
Arch Linux focuses on simplicity of design, meaning that the main focus involves creating an environment that is straightforward and relatively easy for the user to understand directly, rather than providing polished point-and-click style management tools — the package manager, for example, does not have an official graphical front-end. This is largely achieved by encouraging the use of succinctly commented, clean configuration files that are arranged for quick access and editing. This has earned it a reputation as a distribution for "intermediate and advanced Linux users who aren't afraid of the command line".
Relying on complex tools to manage and build your system is going to hurt the end users. [...] "If you try to hide the complexity of the system, you'll end up with a more complex system". Layers of abstraction that serve to hide internals are never a good thing. Instead, the internals should be designed in a way such that they NEED no hiding.
Installation
The Arch Linux website supplies ISO images that can be run from CD or USB. A simple command line script (pacstrap) is used to install the base system. The installation of additional packages, which are not part of the base system (for example, desktop environments), can be done with either pacstrap, or pacman after booting (or chrooting) into the new installation.
An alternative to using CD or USB images for installation is to use the static version of the package manager Pacman, from within another Linux-based operating system. The user can mount their newly formatted drive partition, and use pacstrap (or pacman with the appropriate command-line switch) to install base and additional packages with the mountpoint of the destination device as the root for its operations. This method is useful when installing Arch Linux onto USB flash drives, or onto a temporarily mounted device which belongs to another system.
Regardless of the selected installation type, further actions need to be taken before the new system is ready for use, most notably by installing a bootloader, creating an initramfs, and configuring the new system.
Pacman
To facilitate regular package changes, pacman (abbreviated from "package manager") was developed by Judd Vinet to provide Arch with its own package manager able to track dependencies.
All packages are managed using the pacman package manager. Pacman handles package installation, upgrades, removal, and downgrades, and features automatic dependency resolution. The packages for Arch Linux are obtained from the Arch Linux package tree and are compiled for either IA-32 or x86-64 architectures. It uses binary packages in the tar.xz format, with .pkg placed before this to indicate that it is a pacman package (giving .pkg.tar.xz).
Repositories
Currently, the following official binary repositories exist:
In addition, there also exist testing repositories that include binary package candidates for other repositories. Currently, the following testing repositories exist:
The staging and community-staging repositories are used for some rebuilds to avoid broken packages in testing.
Also, there are a couple other repositories that include the newest version of certain desktop environments.
The unstable repository was dropped in July 2008 and most of the packages moved to other repositories. In addition to the official repositories, there are a number of unofficial user repositories.
The most well-known unofficial repository is the Arch User Repository, or AUR, hosted on the Arch Linux site. However, the AUR does not host binary packages, hosting instead a collection of build scripts known as PKGBUILDs.
Arch Build System (ABS)
The Arch Build System (ABS) is a ports-like source packaging system that compiles source tarballs into binary packages, which are installed via Pacman. The Arch Build System provides a directory tree of shell scripts, called PKGBUILDs, that enable any and all official Arch packages to be customized and compiled. Rebuilding the entire system using modified compiler flags is also supported by the Arch Build System. The Arch Build System makepkg tool can be used to create custom pkg.tar.xz packages from third-party sources. The resulting packages are also installable and trackable via Pacman.
Arch User Repository (AUR)
In addition to the repositories, the Arch User Repository (AUR) provides user-made PKGBUILD scripts for packages not included in the repositories. These PKGBUILD scripts simplify building from source by explicitly listing and checking for dependencies and configuring the install to match the Arch architecture. Arch User Repository helper programs can further streamline the downloading of PKGBUILD scripts and associated building process. However, this comes at the cost of executing PKGBUILDs not validated by a trusted person; as a result, Arch developers have stated that the utilities for automatic finding, downloading and executing of PKGBUILDs will never be included in the official repositories.
Users can create packages compatible with pacman using the Arch Build System and custom PKGBUILD scripts. This functionality has helped support the Arch User Repository, which consists of user contributed packages to supplement the official repositories.
The Arch User Repository provides the community with packages that are not included in the repositories. Reasons include:
PKGBUILDs for any software can be contributed by ordinary users and any PKGBUILD that is not confined to the Arch User Repository for policy reasons can be voted into the community repositories.
Derivatives
There are multiple distributions which either build on top of Arch Linux or are based on its repositories, including the following:
Rolling releases
Similar to Gentoo, and unlike other major distributions such as Ubuntu and Fedora, Arch Linux does not schedule releases for specific dates but uses a "rolling release" system, with new packages provided daily. Its package management allows users to easily keep systems updated.
Monthly updated ISO installation images are released on every first week of a month. It contains the latest software from the stable repositories and stays unchanged until the following month. In most cases, older versions of the installation image may be used to install Arch Linux. However, the packages installed are as old as the installation image.
Occasionally, manual interventions are required for certain updates, with instructions posted on the news section of the Arch Linux website.
Other platforms
There are several projects working on porting the Arch Linux ideas and tools to other kernels, including PacBSD (formerly ArchBSD) and Arch Hurd, which are based on the FreeBSD and GNU Hurd kernels respectively. There is also the Arch Linux ARM project, which aims to port Arch Linux to ARM-based devices, including the Raspberry Pi.