Our 'Watch' series of articles continues today with a very interesting one where you can see Mac OS X 10.4 Tiger running inside the ReactOS computer operating system, which we believe has come a long way, and it's beginning to look like a viable alternative to Microsoft's Windows 7 or Vista operating systems, perfect for desktop computers and laptops. The ReactOS project recently showcased on YouTube that's possible to virtualize the Mac OS X 10.4 operating system on their free and open-source Windows alternative operating system.