The community behind the Fedora Linux distribution has announced the availability of the Fedora 12 beta. Fedora 12, which is codenamed Constantine, is scheduled for official release in November. The new version ships with updated software and adds a number of improvements to key system components. It also brings a lot of nice virtualization improvements.

One of the major goals for Fedora 12 is to boost the quality of the distro on netbook devices. Changes that help fulfill that goal have been made throughout the entire system. The 32-bit x86 packages are now compiled for i686 by default and have a number of optimizations that will provide a performance increase on computers with Intel's Atom processor ( -mtune=atom ). You can see an interesting discussion about the implications of this change in the IRC logs from a Fedora Engineering Steering Committee meeting.

Power management improvements are also a high priority for this release and could help extend netbook battery life. The developers are integrating a background service called "tuned" that will monitor system usage and adaptively adjusts configuration in order to maximize energy efficiency. There is also an ongoing effort in the Fedora community to track down programs that are needlessly energy-intensive and correct the problems. A new SystemTap-based tool called "scomes" helps determine how individual changes to the system will impact a number of metrics relating to resource consumption.

A special Moblin spin will be introduced with Fedora 12. This will allow users to install a complete Fedora installation with Intel's custom Moblin user experience. Upstream Moblin is already based on Fedora, so there is a lot of synergy between the two projects. The Fedora 12 Moblin spin isn't available yet, but users who want to get an early look can optionally install the Moblin environment in the desktop version of the Fedora 12 beta. You can find installation instructions and additional details in a Fedora mailing list post. We looked at the Moblin user interface earlier this year and tested Ubuntu's Moblin variant on a Dell Mini 10v this month. Moblin shows a lot of promise, but much remains to be done before it's ready for broad adoption.

Virtualization

Fedora 12 brings significant virtualization improvements with a number of intriguing new KVM features. Red Hat has been working on a new kernel memory management feature called kernel same-page merging (KSM) that allows identical memory pages to shared between multiple processes. This is very advantageous for virtualization because it will significantly reduce the memory overhead when users are running multiple virtualized environments with similar contents. KSM is planned for inclusion in Fedora 12.

Using huge pages can considerably increase virtualization performance in KVM. Some improvements to libvirt in Fedora 12 will make it easy for users to take advantage of hugetlbfs, increasing performance by as much as 20 percent in some cases. Another new KVM feature in Fedora 12 is guestfish, a tool built on top of libguestfs that makes it easy to manipulate the contents of a KVM guest disk image. You can see some sample uses at the libguestfs website.

Packaging

Fedora 11 included an optional plugin called yum-presto that allows the package management system to use delta RPMs for updates. This means that you only have to download the changes for the updated packages and not the entire package. This feature is now included by default in Fedora 12. Additionally, the adoption of XZ compression will reduce package size. These improvements will make updates and package downloads go faster.

PackageKit, the package management framework, has also received some intriguing enhancements in Fedora 12. A new customization for the bash shell will detect when the user attempts to run a command from a package that is not installed and will offer to automatically install the package. This is not fully integrated yet, but users who want to test it can install the Packagekit-command-not-found package.

A new PackageKit browser plugin will make it easy for users to install software by clicking on a link on a webpage. This is very similar to Ubuntu's "apt://" URLs and OpenSUSE's one-click installers. The plugin is designed to work in Firefox and Epiphany. Web developers can take advantage of it by using the HTML object tag and specifying package metadata in param subelements. PackageKit developer Richard Hughes offered some additional details and an HTML snippet in a blog entry last year.

Conclusion

Fedora 12 has a lot of compelling technical improvements under the hood. The new virtualization features and netbook-related enhancements are particularly impressive and will bring a lot of value to the distro. Fedora 11 had a lot of rough edges, but the new version appears to be a strong improvement. For more detasils, see the official release notes. The beta is available for download from the Fedora website.