Red Hat has followed up its release of release of Red Hat Enterprise Linux (RHEL) 5.1 two weeks ago with an update to its older RHEL 4 line of operating systems, including kernel updates and hardware tweaks.

Separately, CentOS, a popular Red Hat clone, said its RHEL 5.1 clone should be released in the next few days.

The release of RHEL 4.6 (kernel-2.6.9-67.EL) covers RHEL versions including Advanced Server (AS), Enterprise Server (ES), Workstation (WS), and Desktop.

The company released a set of updated CD ISO images with OS package updates and install-time support and a set of Extras ISO images with third-party package updates, available for download through the Red Hat Network.

New kernel features include updated Infiniband OFED and CIFS support. On the hardware side, Red Hat has updated a number of drivers, added new hardware drivers, and added support for hardware platforms such as cpuid4 emulation for AMD processors.

Other software components got updates, including the Samba networking system, upgraded from 3.0.10 to 3.0.25.

Technology previews included with RHEL 4.6 include the Exchange-compatible Evolution 2.8 email client, OpenOffice 2.0 and GCC 4.1.

On Nov. 8 Red Hat released RHEL 5.1 with improvements to its virtualisation offering  that extends support to virtual guests for Windows XP, Server 2000, Server 2003, and the Windows 2008 beta.

Red Hat said its virtualisation software is now being deployed on more than 18,000 servers, although executives, speaking on a conference call, wouldn't say whether those servers were in full deployment or test environments. The company is under pressure to deliver virtualisation for Red Hat Enterprise Linux that is on par with competitors.

On Nov. 16 CentOS announced that package lists and patches had been completed on CentOS 5.1, with a release tentatively scheduled for the end of this week or early next week.

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