Red Hat Enterprise Linux 5.5 (RHEL) is now available in early beta, providing users of Red Hat's flagship operating system with bug fixes and an early look at some new features, too. With RHEL 5.5, Red Hat (NYSE: RHT) is continuing to build on the RHEL 5 base, which was launched in 2007. Its most recent update was the RHEL 5.4 release, which officially debuted in September and was notable for its new KVM virtualization base. It's a base that Red Hat is further expanding now with RHEL 5.5, thanks to a new run-time memory allocation feature for KVM virtual guests.