Virtualization for embedded systems has many implementations in which two or more operating systems coexist to gain the benefits of each. One approach puts Microsoft Windows and a Real-Time Operating System (RTOS) together.
Much is being said about virtualization these days in the softwareworld. Simply stated, virtualization is about getting multiple OSs to run on the same computing platform at the same time. Virtualization has been cited as a key technology for getting the most performance out of the newest multicore processors. But just as not all computing applications are the same, not all virtualization approaches are appropriate for all applications.
refer: http://embedded-computing.com/articles/real-time-general-purpose-unite-via-virtualization/