Back in 2006, Microsoft decided to borrow a Linux distribution. Microsoft, which has felt little negative direct effect from the Linux operating system, needed to ensure it could skew the open-source business model in its favor, by levying a patent FUD tax on anyone who chose to use Linux.
Microsoft has paraded its Linux in terms of customer choice and customer protection, but both are complete canards. Mandriva Linux is just as interoperable with Microsoft Windows as Microsoft's SUSE, is. The same is true for a wide variety of Linux distributions - they are all as interoperable with Windows as any officially blessed by Microsoft.