Linux 3.0 is official here, but users expecting a swathe of fundamental changes to the kernel will find little to surprise them as the project celebrates its twentieth birthday.
Announced by Linux founder Linus Torvalds - on his Google+ profile, oddly enough - Linux 3.0 was expected to be earlier this month, but the discovery of a small bug in pathname lookups by Hugh Dickins lead to some last-minute changes being required.
While the version number takes a leap, Linux 3.0 isn't all that new: in reality, it's little more than 2.6.40 with a revamped numbering scheme. Now, Linux kernels - which form the heart of the GNU/Linux open-source operating system - will be identified with two numbers, rather than three.
"I decided to just bite the bullet, and call the next version 3.0," Torvalds explained on the Linux Kernel Mailing List back in May. "The whole renumbering was discussed at last years Kernel Summit, and there was a plan to take it up this year too. But let's face it - what's the point of being in charge if you can't pick the bike shed color without holding a referendum on it? So I'm just going all alpha-male, and just renumbering it. You'll like it."
It's a fundamental change in the way versions are tracked, and is likely to cause a few problems for early adopters: while Linux 3.0 adds a work-around for applications that expect a kernel to have a kernel version number to have three digits, many packages track compatible kernel versions by looking for the '2.6' at the start. These will choke on an upgrade to 3.0, and require updating beforehand.
Beyond the changes to the version numbering system, there's little in the kernel itself that is revolutionary. "The point is that 3.0 is just about renumbering, we are very much not doing a KDE-4 or a Gnome-3 here. No breakage, no special scary new features, nothing at all like that," Torvalds explained. Following the update roadmap for Linux 2.6, Linux 3.0 adds a storage backend for the Xen hypervisor, improvements to the Btrfs file system, and enhancements to the drivers for various graphics processors and peripheral devices.
A disabled-by-default just-in-time compiler for the network packing filtering portion of the kernel promises performance improvements for 64-bit systems when enabled, while rudimentary support for Wake on Wireless LAN technology has been added.
Perhaps the biggest modification in Linux 3.0 is the start of work to improve the project's ARM implementation, famously criticised by project founder Torvalds for being bloated and inelegant. With ARM processors expected to make significant inroads in the laptop and low-power desktop markets over the next couple of years, that's an important process but one which will take significant time to complete.
While it will take time for distributions to offer the Linux 3.0 kernel to their users, the full source code is available for download and compilation by more adventurous users now from Kernel.org.