Issue #4 February 2005

Introducing
Red Hat Enterprise Linux 4

Red Hat® Enterprise Linux® 4, the defining milestone in the evolution of the Enterprise operating system, boasts the 2.6 kernel, security-enhanced Linux, Firefox web browser, Evolution 2.0, and enough desktop enhancements to make your head spin. This article presents an overview of the latest version of Enterprise Linux. For more information refer to redhat.com and the the section called “Further reading”.

Enterprise Linux 4 supports multiple hardware architectures including:

  • Intel x86-compatible (32bit)
  • Intel Itanium (64bit)
  • Advanced Micro Devices AMD64 (64bit) and Intel EM64T
  • IBM POWER series (eServer iSeries and eServer pSeries)
  • IBM Mainframe (eServer zSeries and S/390)

One of the reasons Red Hat is able to support so many architectures is that they all come from the same source code built specifically for different architectures. This not only simplifies the build process, but it also simplifies the administration and support of Enterprise Linux on multiple architectures. Not all architectures are supported on all variants of Enterprise Linux. Refer to the overview paper for more details.

One of the reasons Red Hat is able to support so many architectures is that they all come from the same source code built specifically for different architectures.

The Enterprise Linux offerings are the same as v.3:

  • Red Hat Enterprise Linux AS: High-end server such as database and web servers
  • Red Hat Enterprise Linux ES: Entry/mid-level server such as mail, file, and print servers
  • Red Hat Enterprise Linux WS: High-end client for software development, CAD applications, and other demanding tasks
  • Red Hat Desktop: General purpose client for one processor systems

Upgrades from one family member to another is possible because all the features of the desktop and mid-level products are also available in the high-end server product.

Typical commercial deployment
Figure 1. Typical commercial deployment

The 2.6 kernel is included in this latest version of Enterprise Linux. While Red Hat backported many of the key features from the 2.6 kernel into the 2.4 kernel offered in previous versions of Enterprise Linux, this latest version still includes some significant improvements including selectable I/O elevators, Reverse Map Virtual Memory, support for multi-core processors, and the sys_epoll system call.

Red Hat Enterprise Linux 4 is the first commercial product to include Security-Enhanced Linux (SELinux). SELinux is a Mandatory Access Control (MAC) security system for Linux, which allows finer-grain control over which users and what processes can access the filesystem. By default, a targeted policy is enabled. The default targeted policy affects the following daemons only: dhcpd, httpd, mysqld, named, nscd, ntpd, portmap, postgres, snmpd, squid, and syslogd.

Red Hat Enterprise Linux 4 is the first commercial product to include Security-Enhanced Linux (SELinux).

For an overview of how Red Hat has been involved in its development and to learn more about the first SELinux Symposium, check out this month's SELinux article.

If you read last month's article Coming soon to Enterprise Linux, you will be glad to know all these features made it into version 4 along with the GNOME 2.8 desktop.

Other desktop improvements include the Firefox web browser, Evolution 2.0 for email, calendaring, and contact management, OpenOffice.org office suite, GAIM instant messenger, The GIMP v.2 image tool, and Vino VNC. Red Hat Desktop 4 also includes RealPlayer 10 for SMIL, MP3, Flash, and RealAudio/RealVideo support.

For more details on the new technical features, refer to An Overview of the Red Hat Enterprise Linux 4 Product Family.

In addition, Red Hat Enterprise Linux:

  • Supports UTF-8 encoding by default for Chinese, Japanese, and Korean locales.
  • Uses IIIMF for input of Chinese, Japanese, and Korean by default.
  • Supports 5 Indian (Indic) languages: Bengali, Gujarati, Hindi, Punjabi, and Tamil. In addition, the high-quality Lohit font family for the supported languages has been included.
  • Includes Subversion 1.1, a version control system designed to replace CVS.
  • Includes Logical Volume Manager (LVM) 2.0 and system-config-lvm, a graphical tool for configuring LVM.
  • Utilizes udev to dynamically manage the /dev/ directory.

If you still need more options, Red Hat offers four optional subscriptions:

Red Hat Application Server
This offering provides a J2EE® 1.4 standards-compliant application server including a web container based on Tomcat and an EJB container based on JOnAS.
Red Hat Global File System (GFS)
GFS is a highly functional cluster-wide filesystem that offers concurrent read-write filesystem access from hundreds of nodes.
Red Hat Cluster Suite
High availability failover clustering can be added to Enterprise Linux.
Red Hat Developer Suite
This addition includes a comprehensive integrated development environment based on Eclipse.

Further reading

Want to know what Red Hat's partners think about Enterprise Linux 4? Watch the videos to find out.

For more in-depth technical information, read the following articles from past issues of the magazine:

Still want to know more? Check out the related whitepapers.