MED-V is a desktop virtualization product planned to become part of the Microsoft Desktop Optimization Pack (MDOP) MED-V is based on Microsoft's acquisition of Kidaro, a company that made desktop virtualization tools, and aims to resolve a number of problems with application compatibility on newer OSs. One such problem is applications that run on Windows XP or Windows 2000 but aren't compatible with Windows 7 and Windows Vista. A large amount of testing and application "shimming" (a process that lies to an application to make it run on an OS it shouldn't) is required to make sure legacy applications will run on Vista. The effort needed can be a major obstacle to adopting newer OSs and it's quite possible that a given application simply can't run on Windows 7 or Vista.
You have two choices today for applications that can't run on a new desktop OS. You can run the application on a terminal server (assuming the application can run on a terminal server) and have users remote to the terminal server to run the application. Your other option is to use a client virtualization solution, such as Virtual PC, to run a legacy OS image, such as Windows XP, that can then host the legacy application. The virtual approach means the user has their normal desktop and another desktop that represents the Virtual PC image of XP. This is confusing for most users, with two Start buttons, two sets of menus, two file systems, two desktops, and so on.
MED-V builds on the Virtual PC approach by using Virtual PC 2007 as a client-side virtualization platform to host an XP or Win2K image that runs the legacy applications. The MED-V application then seamlessly integrates the application running on the legacy OS with the user's main desktop. MED-V integrates Start menu options, notification tray icons, clipboard sharing and file system interoperability between the VM and the local OS. The architecture is shown here.
To learn more and to read the entire article at its source, please refer to the following page, What is Microsoft Enterprise Desktop Virtualization (MED-V)?