Friday, August 28, 2009

Windows XP Mode for Windows 7 doesn't work with VDI

XP Mode won’t run on any virtual machine running on a hypervisor. Virtual Desktops directly running on blades (no hypervisor) will work however. Med-V is the management bit, part of MDOP that is used to manage the virtual images.


XP Mode uses a hardware assisted version of Microsoft Virtual PC to allow the use of XP compatible applications on Vista/7. You can’t use hardware assisted Virtual PC on a machine running on a hypervisor as it requires the hardware assist (VT) from the processor. Virtual Processors don’t have hardware assist. The current version of XP mode uses Virtual PC, but would one would suspect that this will change to an embedded Hyper-V at some stage.

So how does this affect me?

If you thought that VDI was an easy hop to migrating to Windows 7, think again, the much touted Microsoft application compatibility pieces won’t work without using another mechanism.

Will XP Mode run on my laptop?

Only if your chipset supports hardware assist, and if your vendor has added the ability to enable it in your BIOS!

Won’t Citrix Application Streaming/App-V/ThinApp/Altiris SVS etc. resolve this?

Nope, if the application is packaged as a virtual application, it won’t change the OS compatibility of the said application. If it doesn’t work using traditional installation, it won’t work isolated either. Remember its isolated from other applications, not the OS.

So how do I get those pesky XP applications running in my VMs?

Two ways:
1. You could use XenApp running Windows 2003, which combined with either XenApp Streamed Applications or App-V (to provide isolation and application sociability) would support almost all XP applications.
2. You could use VM hosted Apps. Citrix is releasing application publishing from a desktop OS in Q3 - more info here

Hang on, what about Laptop hypervisors, Citrix/Intel Project Independence and the like?

Same story, Windows 7 running on a desktop hypervisor won’t be able to use XP Mode. The difference here is that you can run the XP applications on a second VM on the same device, moreover there will even be elegant ways of accessing the XP applications from within the Windows 7 desktop. Better or worse than XP mode? - Performance will probably be better as you are using a type 1 hypervisor for the application.


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