What exactly is included in the Microsoft VDA license cost?

What do I get out of the Microsoft VDA license?

Microsoft's VDA license subscription gives a device the right to access remote virtual machines running a desktop operating system, such as Windows XP or Windows 7. It extends many Software Assurance rights to devices that aren't eligible for or don't have that subscription and offers some additional perks.

The Virtual Desktop Access (VDA) license fills a gap in Microsoft's licensing model; the company does not license OSes running in virtual machines directly (except for Windows 7's XP Mode), and Software Assurance (SA) -- the usual way to license access to VMs -- requires jumping through some hoops.

The right to run Windows in a VM is usually gained by adding SA, Microsoft's upgrade rights subscription, to Windows on the PC that is accessing the remote VM. If someone accesses a virtual Windows 7 desktop from a laptop, for example, he or she must have an SA subscription for the Windows OS that is installed on that laptop.

But users can't add SA to any device any time they want. First, the device accessing the VM must run a full copy of Windows (not an upgrade, which is the only desktop Windows OS license sold through volume licensing). Second, SA must be added within 90 days of the device being purchased. Wait longer and SA can no longer be added.

How would you license access to virtual desktops if you waited too long? What if your device runs Linux? What if it's a thin terminal using Windows CE? What if it's an iPad? None of those devices is eligible for SA on Windows, which has previously ruled them out for access to virtual Windows desktops.

That is where the Microsoft VDA license comes to the rescue.

A VDA subscription costs more (about $65 to $95 a year, depending on the customer's discount) than SA ($32 to $55 a year), but the following are possible with a VDA subscription:

• The VDA device may access remote Windows computers, virtual or physical;
• The primary user of the VDA-licensed device may access a remote VM from any third-party device if the user is off-premises;
• A Microsoft Desktop Optimization Pack subscription may be purchased for the device;
• Companion Subscription Licenses (which permit non-Windows devices or non-corporate-owned Windows devices to access remote VMs) may be purchased for up to four additional devices; and
• The primary user of the VDA-licensed device may run Windows To Go (Windows 8 on a flash drive) on any device.