Microsoft have stunned the Linux world by submitting source code for the kernel. So when did this happen? On Monday the 20th of July 2009. Remember this date, mark it in your diaries.
So what did they submit? The code consists of four drivers that are part of a technology called Linux Device Driver for Virtualization. These drivers, once added to the Linux kernel, will provide the hooks for any distribution of Linux to run on Windows Server 2008 and its Hyper-V hypervisor technology. The surprising thing is that it was submitted for inclusion in the Linux kernel under a GPLv2 license.