Inside MDOP: MED-V and App-V

Inside the Microsoft Desktop Optimization Pack, you’ll find MED-V and App-V. Both provide ways to deliver applications to your desktop, but they solve different problems.

MED-V is good for resolving incompatibilities between an application and Windows 7. By creating and distributing a full instance of Windows XP from which the application runs, users can access applications that would not run on Windows 7 otherwise. It’s also applicable for websites that must run in a browser like Internet Explorer 6. For example, an IE 6 instance can be launched from within the MED-V managed OS and be controlled with policies to limit the sites that are available from the less secure browser.

In general, a MED-V hosted application is isolated from the primary operating system, though the clipboard can be shared to allow for basic copy/paste functionality between applications and printer redirection can ensure users can print from the MED-V application. If your application is very task specific and does not require direct interactions with other applications on the primary operating system, MED-V can allow you to upgrade to Windows 7 before solving the application compatibility issue.

Application Virtualization (App-V) creates and delivers a single application in a package, instead of a full instance of an operating system like MED-V. The application package is cached on the local machine, but in not installed in the traditional sense. By not installing application files directly and keeping them isolated in their packages, App-V can eliminate conflicts between two applications that might otherwise cause failures when installed on the same machine. An example would be where Office 97 and later versions of Office share DLLs with similar names, but have functionality that doesn't work with both products.

App-V also eases application upgrades and maintenance by allowing IT to update single packages that are then streamed to users on demand, instead of having to managing multiple local installations of software. Because applications deployed with App-V execute locally on the desktop they utilize the CPU and memory resources of the local machine instead of those on the server. Inter-application communication with other App-V applications and applications installed locally are preserved, allowing for cut and paste, OLE, and all other standard operations. However applications that install their own device driver, like a print driver, may not be suitable for complete virtualization.

In a nutshell, App-V can help you develop a more robust and controlled application management lifecycle, while allowing support for some legacy applications that don’t play well with new versions. MED-V builds a “temporary” bridge between applications that only work on older operating systems, providing some wiggle room so you can potentially upgrade your desktops without having to wait until all your applications are supported.

Depending on the needs of your organization, MED-V or App-V might be just what you need to solve a lingering application compatibility issue.