In a message entitled, “Super Kernel Sunday!” to the LKML (Linux Kernel Mailing List), Linus Torvalds announced news far more important than the Colts beating the Bears — to serious Linux users, anyway. The newest stable version of the Linux kernel, version 2.6.20, has been released.
Torvalds, with his tongue firmly planted in his cheek, went on “Before downloading the actual new kernel, most avid kernel hackers have been involved in a 2-hour pre-kernel-compilation count-down, with some even spending the preceding week doing typing exercises and reciting PI to a thousand decimal places.”
And, Torvalds added, “As ICD head analyst Walter Dickweed put it: ‘Releasing a new kernel on Superbowl Sunday means that the important ‘pasty white nerd’ constituency finally has something to do while the rest of the country sits comatose in front of their [65-inch] plasma screens.’”
After some more fun, Torvalds moved on to business. “I tried rather hard to make 2.6.20 largely a ‘stabilization release.’ Unlike a lot of kernels lately, there aren’t really any big fundamental changes to some core infrastructure area, and while we always have bugs, I really am hoping that we fixed many more than we introduced,” wrote Torvalds.
The one major new addition to the 2.6.20 kernel is the long-awaited addition of KVM (Kernel-based virtual machine for Linux). KVM, like Xen and OpenVZ, is an open-source virtualization platform.
KVM works only on the latest x86 processors that include virtualization extensions. These include Intel’s VT (Virtualization Technology aka Vanderpool) and AMD’s AMD-V (aka Pacifica) technologies. With chips that support these technologies, such as Intel’s Core 2 Duo processor, virtualization programs that support these extensions can run much more efficiently.
With Linux 2.6.20, KVM consists of a loadable kernel module, kvm.ko, which implements the core virtualization infrastructure, along with a processor specific module, kvm-intel.ko or kvm-amd.ko, which supports the appropriate instruction set. At this time, KVM also requires a modified QEMU to work properly. QEMU is an open-source VM (virtual machine) monitor, or “hypervisor.”
With KVM and the right chips, users will be able run multiple VMs running both unmodified Linux and Windows. Each VM has its own private virtualized hardware: a network card, disk, graphics adapter, and so on.
In one early test of a Linux 2.6.20 with a KVM release candidate, “KVM was not the clear winner in all of the benchmarks,” according to a review by Michael Larabel on Phoronix.com. It did do well, however, and its strong points reportedly included “high performance, stable, no modifications of the guest operating system are necessary, and a great deal of other capabilities (e.g. using the Linux scheduler).”
Source code to Sunday’s Linux 2.6.20 release can be downloaded from kernel.org. Expect to see it begin showing up in your favorite distro in the coming months.
Vista, meanwhile remains at version 1.0.
A version of this story first appeared in Linux-Watch.