Red Hat Enterprise Linux

Red Hat Enterprise Linux

Red Hat Enterprise Linux 5's default GNOME desktop
Company / developer	Red Hat
OS family	Linux
Working state	Current
Source model	Open source
Latest stable release	5.2/ May 21, 2008 (2008-05-21); 101 days ago
Package manager	RPM Package Manager
Kernel type	Monolithic kernel
License	Various
Website	www.redhat.com/rhel/

Red Hat Enterprise Linux is a Linux distribution produced by Red Hat and targeted toward the commercial market, including mainframes. Red Hat commits to supporting each version of Red Hat Enterprise Linux for 7 years after its release. All of Red Hat's official support, all of Red Hat's training and the Red Hat Certification Program center on the Red Hat Enterprise Linux platform. Red Hat Enterprise Linux is often abbreviated to RHEL, but Red Hat is now attempting to discourage this^[1].

New versions of Red Hat Enterprise Linux are released every 18 to 24 months. When Red Hat releases a new version of Red Hat Enterprise Linux, customers may upgrade to the new version at no additional charge as long as they are in possession of a current subscription (i.e. the subscription term has not yet lapsed).

Red Hat's first Enterprise offering (Red Hat Linux 6.2E) essentially consisted of a version of Red Hat Linux 6.2 with different support levels, and without separate engineering.

The first version of Red Hat Enterprise Linux to bear the name originally came onto the market as "Red Hat Linux Advanced Server". In 2003 Red Hat rebranded Red Hat Linux Advanced Server to "Red Hat Enterprise Linux AS", and added two more variants, Red Hat Enterprise Linux ES and Red Hat Enterprise Linux WS.

Verbatim copying and redistribution of the entire Red Hat Enterprise Linux distribution is not permitted due to trademark restrictions.^[2] However, there are several redistributions of Red Hat Enterprise Linux minus trademarked features (such as logos and the name).

Variants

As of 2005 Red Hat distributed four variants of Red Hat Enterprise Linux:

• Red Hat Enterprise Linux AS for mission-critical/enterprise computer systems.
• Red Hat Enterprise Linux ES for supported network servers
• Red Hat Enterprise Linux WS for technical power-user desktops or high-performance computing
• Red Hat Desktop – for multiple deployments of single-user desktops

There are also "Academic" editions of the Desktop and Server variants. They are offered to schools and students, are less expensive, and are provided with Red Hat technical support as an optional extra. Web support based on number of customer contacts can be purchased separately.

People sometimes mistakenly refer to ES as "Enterprise Server", in contrast to AS (Advanced Server). This may be because Novell has a server distribution called SUSE Linux Enterprise Server (SLES). However, nowhere on its site or in its literature does Red Hat say what AS, ES and WS stand for.

In Red Hat Enterprise Linux 5 there are new editions that substitute former Red Hat Enterprise Linux AS/ES/WS/Desktop:^[3]

• Red Hat Enterprise Linux Advanced Platform (former AS)
• Red Hat Enterprise Linux (former ES) (limited up to 2 CPUs)
• Red Hat Enterprise Linux Desktop with Workstation and Multi-OS option
• Red Hat Enterprise Linux Desktop with Workstation option (former WS)
• Red Hat Enterprise Linux Desktop with Multi-OS option
• Red Hat Enterprise Linux Desktop (former Desktop)

Red Hat also announced its Red Hat Global Desktop Linux edition "for emerging markets"^[4]

Relationship to free or community distributions

Originally, Red Hat based Red Hat Enterprise Linux on Red Hat Linux, but using a much more conservative release cycle. Later versions leveraged technologies from Fedora which is a community distribution and project that Red Hat sponsors. Roughly every third version of Red Hat Linux (RHL) or Fedora forms the basis for a version of Red Hat Enterprise Linux^[5], thus:

• Red Hat Linux 6.2 → Red Hat Linux 6.2E
• Red Hat Linux 7.2 → Red Hat Enterprise Linux 2.1
• Red Hat Linux 9 → Red Hat Enterprise Linux 3
• Fedora Core 3 → Red Hat Enterprise Linux 4
• Fedora Core 6 → Red Hat Enterprise Linux 5
• Fedora 9 / Fedora 10 → Red Hat Enterprise Linux 6 (projected)

Rebuilds

Main article: Red Hat Enterprise Linux derivatives

Originally, Red Hat's enterprise product, then known as Red Hat Linux, was made freely available to anybody who wished to download it, while Red Hat made money from support. Red Hat then moved towards splitting its product line into Red Hat Enterprise Linux which was designed to be stable and with long-term support for enterprise users and 'Fedora' as the community distribution and project sponsored by Red Hat. They use trademarks to prevent verbatim copying of Red Hat Enterprise Linux.

Since Red Hat Enterprise Linux is based completely on free and open source software, Red Hat makes available the complete source code to its enterprise distribution through its FTP site to anybody who wants it. Accordingly, several groups have taken this source code and compiled their own versions of Red Hat Enterprise Linux, typically with the only changes being the removal of any references to Red Hat's trademarks and pointing the update systems to non-Red Hat servers. Groups which have undertaken this effort include CentOS (the most popular as of June 2007),^[6] StartCom Enterprise Linux, Pie Box Enterprise Linux, Scientific Linux, White Box Enterprise Linux and Lineox. Oracle Corporation has also recently come out with its own repackaging of Red Hat Enterprise Linux called Oracle Enterprise Linux as part of its Unbreakable Linux program but does not provide a free mechanism for applying updates without paying a service fee as with Red Hat.

Rebuilds of Red Hat Enterprise Linux are free but do not get any commercial support or consultancy services from Red Hat and lack any software, hardware or security certifications. Also, the rebuilds do not get access to Red Hat services like Red Hat Network .

Commercial products based on Red Hat Enterprise Linux

Main article: Commercial products based on Red Hat Enterprise Linux

A number of commercial vendors use Red Hat Enterprise Linux as a base for the operating system in their products. The most well-known is the Console Operating System in VMware ESX Server.

Version history

The various Red Hat Linux version have little different Errata Support Policies

• Red Hat Linux 6.2E (Zoot), 2000-03-27
• Red Hat Enterprise Linux 2.1 AS (Pensacola), 26 March 2002
• Red Hat Enterprise Linux 2.1 ES (Panama), May 2003
• Red Hat Enterprise Linux 3 (Taroon), 2003-10-22, kernel 2.4.21-4
  • Update 1, 16 January 2004 (Release Notes) kernel 2.4.21-9
  • Update 2, 18 May 2004
  • Update 3, 3 September 2004
  • Update 4, 21 December 2004
  • Update 5, 20 May 2005
  • Update 6, 28 September 2005, kernel 2.4.21-37 (Release Notes)
  • Update 7, 15 March 2006
  • Update 8, 20 July 2006, kernel 2.4.21-47
  • Update 9, 15 June 2007, kernel 2.4.21-50
• Red Hat Enterprise Linux 4 (Nahant), 2005-02-15, kernel 2.6.9-5
  • 4.1, also known as Update 1, 9 June 2005^[7]
  • 4.2, also known as Update 2, 5 October 2005 (Release Notes), kernel 2.6.9-22
  • 4.3, also known as Update 3, 7 March 2006 (Release Notes), kernel 2.6.9-34
  • 4.4, also known as Update 4, 11 August 2006 (Release Notes) kernel 2.6.9-42
  • 4.5, also known as Update 5, 1 May 2007 (Release Notes) kernel 2.6.9-55
  • 4.6, also known as Update 6, 15 November 2007 (Release Notes) 2.6.9-67
  • 4.7, also known as Update 7, 24 July 2008 (Release Notes)
• Red Hat Enterprise Linux 5 (Tikanga), (Release notes) 2007-03-14, kernel 2.6.18-8
  • 5.1 (also known as Update 1), (Release Notes) 2007-11-07
  • 5.2 (also known as Update 2), (Release Notes, single file) 2008-05-21

References

External links

• Red Hat Enterprise Linux homepage
• Brian Stevens, CTO and vice president of engineering, Red Hat on why Red Hat Enterprise Linux is "The Business OS for Flexibility and Value"
• Red Hat Enterprise Linux at DistroWatch