CentOS is a Linux distribution derived from Red Hat Enterprise Linux sources. It is developed by a small team and supported by an active user community worldwide. CentOS aims to be binary compatible with Red Hat Enterprise Linux and provides a free alternative to Red Hat's paid subscription model.

1. CentOS stands for Community ENTerprise Operating System. CentOS is an Enterprise-class Linux Distribution derived from sources freely provided to the public by a prominent North American Enterprise Linux vendor. CentOS conforms fully with the upstream vendors redistribution policy and aims to be 100% binary compatible developed by a small but growing team of core developers. In turn the core developers are supported by an active user community including system administrators, network administrators, enterprise users, managers, core Linux contributors and Linux enthusiasts from around the world. CentOS has numerous advantages over some of the other clone projects including: an active and growing user community, quickly rebuilt, tested, and QA'ed errata packages, an extensive mirror network , developers who are contactable and responsive, multiple free support avenues including IRC Chat , Mailing Lists , Forums , a dynamic FAQ . Commercial support is offered via a number of vendors. a community-supported,mainly free software operating system based on Red Hat Enterprise Linux . It exists to provide a free enterprise class computing platform and strives to maintain 100% binary compatibility with its upstream distribution.

2. CentOS is an Enterprise Linux distribution based on the freely available sources from Red Hat Enterprise Linux . Each CentOS version is supported for 7 years (by means of security updates). A new CentOS version is released every 2 years and each CentOS version is periodically updated (roughly every 6 months) to support newer hardware. This results in a secure, low-maintenance, reliable, predictable and reproducible Linux environment.

3. The CentOS Project is the name of the Organization that produces CentOS. We are not a part of any other organization. The CentOS Development Team The group of people who build CentOS are known as the CentOS Development Team. The team includes: CentOS-2 - John Newbigin CentOS-3 - Tru Huynh, Pasi Pirhonen CentOS-4 - Johnny Hughes, Karanbir Singh, Pasi Pirhonen, Jim Perrin, Ralph Angenendt CentOS-5 - Johnny Hughes, Karanbir Singh, Jim Perrin, Ralph Angenendt, Patrice Guay Security, Web, Infrastructure - Donavan Nelson, Russ Herrold Forum Administrators - Fabian Arrotin (arrfab), Akemi Yagi (toracat), Phil Perry (NedSlider), Phil Schaffner (pschaff), Alan Bartlett (burakkucat). Mirror Administration - Tru Huynh QA Team Leader - Tim Verhoeven

4. Planet CentOS developer blogs . CentOS users as a group are a community of open source contributors and users. Typical CentOS users are organizations and individuals that do not need strong commercial support in order to achieve successful operation. CentOS 2, 3, 4 and 5 are built from publicly available open source SRPMS provided by a prominent North American Enterprise Linux vendor. CentOS conforms fully with the upstream vendors redistribution policies and aims to be 100% binary compatible. (CentOS mainly changes packages to remove upstream vendor branding and artwork) .

5. CentOS-5 is a freely distributable OS built from the source at: ftp://ftp.redhat.com/pub/redhat/linux/enterprise/5Client/en/os/SRPMS ftp://ftp.redhat.com/pub/redhat/linux/enterprise/5Server/en/os/SRPMS CentOS-5 supports the x86 and x86_64 (AMD64 and Intel EMT64) architectures. Support for the ia64, ppc, and sparc architectures is in progress. Updates are distributed via YUM repositories. CentOS-4 is a freely distributable OS built from the source at: ftp://ftp.redhat.com/pub/redhat/linux/enterprise/4/en/os/i386/SRPMS CentOS-4 supports x86 (i586 and i686), x86_64 (AMD64 and Intel EMT64), ia64, ppc, alpha, sparc, s390, and s390x architectures (The ppc and sparc architectures are currently BETA). Updates are distributed via YUM repositories. CentOS-3 is a freely distributable OS built from the source at: ftp://ftp.redhat.com/pub/redhat/linux/enterprise/3/en/os/i386/SRPMS CentOS-3 supports x86 (i586 and i686), x86_64 (AMD64 and Intel EMT64), ia64, s390 and s390x architectures. Updates are distributed via YUM repositories. CentOS-2 is a freely distributable OS built from the source at: ftp://ftp.redhat.com/pub/redhat/linux/enterprise/2.1AS/en/os/i386/SRPMS / CentOS-2 supports x86 CPUs. Updates are distributed via yum repositories.

6. CentOS exists to provide a free enterprise class computing platform to anyone who wishes to use it. CentOS 2, 3, and 4 are built from publically available open source SRPMS provided by a prominent North American Enterprise Linux vendor. CentOS conforms fully with the upstream vendors redistribution policies and aims to be 100% binary compatible. (CentOS mainly changes packages to remove upstream vendor branding and artwork.). CentOS is designed for people who need an enterprise class OS without the cost or support of the prominent North American Enterprise Linux vendor. Neither the CentOS Project (we who build CentOS) nor any version of CentOS is affiliated with, produced by, or supported by the prominent North American Enterprise Linux vendor. Neither does our software contain the upstream vendor's product ... although it is built from the same open source SRPMS as the upstream enterprise products.

7. Our purpose is to provide stable Linux solutions for organizations and individuals who do not need strong commercial support to achieve successful operation. To meet that overall goal, we strive to achieve: * easy maintenance * self hosting distribution (one that can build on itself) * suitability for long term use in production environments * friendly environment for users and package maintainers * long-term support of the core * active development * community infrastructure * open management * open business model * commercial support - offered by partner vendors CentOS uses the original sources whenever possible. Under normal circumstances CentOS will NOT add patches to original upstream source packages. The vast majority of changes made will be made to comply with the upstream vendor's re-distribution policies concerning trademarked names or logos. Any other changes made will be spelled out in the Release Notes for the individual CentOS product.

8. There are several repositories provided by CentOS and other 3rd party developers that offer software packages that are not included in the default base and updates repositories. While no list can be 100% complete, as anyone may announce an archive, it represents some major efforts and provides a summary of what each repository offers. These repositories have varying levels of stability, support and cooperation within the CentOS community. *CentOS Extras This repository contains items that provide additional functionality to CentOS without breaking upstream compatibility or updating base components. The CentOS development team have tested every item in this repository and they all work with CentOS. They have not been tested by the upstream provider and are not available in the upstream products. This repository is shipped with CentOS and is enabled by default. *CentOS Plus This repository contains items that actually upgrade certain base CentOS components. This repo will change CentOS so that it is not exactly like the upstream provider's content. The CentOS development team have tested every item in this repository and they all work with CentOS. They have not been tested by the upstream provider and are not available in the upstream products. This repository is shipped with CentOS but is not enabled by default.

9. * CS/GFS This repository is a rebuild of the upstream provider's Cluster Suite and Global File System for CentOS-4 and provides support for the x86 and x86_64 architectures. The CentOS development team have tested every item in this repository and they all work under CentOS-4. This repository is not shipped by default with CentOS-4 , although the repository config file can be found at http://mirror.centos.org/centos-4/4/csgfs/CentOS-csgfs.r epo . *CentOS-Testing This repository is a proving ground for packages on their way to CentOSPlus and CentOS Extras. They may or may not replace core CentOS packages and are not guaranteed to function properly . These packages install but are waiting for feedback from testers as to their functionality and stability. Packages in this repository will come and go during the development period, so it should not be left enabled or used on production systems. This repository is intentionally not shipped with CentOS by default, although the repository config files can be found at: CentOS 4: http://dev.centos.org/centos/4/CentOS-Testing.repo CentOS 5: http://dev.centos.org/centos/5/CentOS-Testing.repo *CentOS-Fasttrack This repository will contain bugfix and enhancement updates, issued from time to time, between update sets that may be rolled into the next update set. See this Readme file for more details. This repository has a config file located here for CentOS-4.

10. *contrib This repository contains packages contributed by CentOS users which do not overlap with any of the core distribution packages. These packages have not been tested by the CentOS developers and may not track the upstream version releases very closely. *debuginfo This repository contains packages with debugging symbols generated when the primary packages were built. No repo config is provided by default. Tools like oprofile, crash, and systemtap require debuginfo packages. These packages are found at http://debuginfo.centos.org/

11. Company / developer The CentOS Project OS family Unix-like Working state Current Source model Free and open source software Initial release December 1, 2003 (2003-12-01) Latest stable release 5.4 (October 21, 2009; 6 months ago (2009-10-21)) [ +/− ] Marketing target free computing (include Servers , Workstations , Mainframes , Desktops ) Available language (s) Multilingual Package manager RPM Package Manager Supported platforms IA-32 , x86-64 , PowerPC , i386 , s390 , s390x Kernel type Monolithic ( Linux ) Userland GNU Default user interface GNOME and KDE License GNU GPL & Various others. Official website www.centos.org

12. Red Hat Enterprise Linux is available only through a paid subscription service that provides access to software updates and varying levels of technical support. The product is largely composed of software packages distributed under open source licenses , and the source code for these packages is made public by Red Hat. CentOS developers use Red Hat's source code to create a final product very similar to Red Hat Enterprise Linux. Red Hat's branding and logos are changed because Red Hat does not allow them to be redistributed. CentOS is available free of charge. Technical support is primarily provided by the community via official mailing lists, web forums, and chat rooms. The project is not affiliated with Red Hat and thus receives no financial or logistical support from the company; instead, the CentOS Project relies on donations from users and organizational sponsors. CentOS version numbers have two parts, a major version and a minor version. The major and minor version numbers respectively correspond to the major version and update set of Red Hat Enterprise Linux from which the source packages used to build CentOS are taken. For example, CentOS 4.4 is built from the source packages from Red Hat Enterprise Linux 4 update 4 . Since mid-2006, starting with version 4.4 (formerly known as Red Hat Enterprise Linux 4.0 update 4), Red Hat has adopted a versioning convention identical to that of CentOS, e.g., Red Hat Enterprise Linux 4.5 .

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