Tue, May 05, 2009 — InfoWorld — An October surprise -- that's how many are interpreting Microsoft's 11th-hour revelation that it will be providing a virtualized copy of Windows XP as a free compatibility add-on to Windows 7 Professional, Ultimate, and Enterprise editions.

The idea is to entice potential upgrade fence-sitters into taking the Windows 7 plunge by addressing one of the more widely cited concerns about the product: It will break legacy, Windows XP-era applications. And based on the amount of buzz surrounding this unexpected new feature, it would seem that Microsoft has hit a home run with its Windows XP mode announcement.

[ Learn how to ease the XP-to-Windows-7 migration. | Will Windows 7 improve on Vista's performance? See "Windows 7 unmasked." ]

Yet I fear that much of this excitement will turn to disappointment as IT shops begin to understand just what XP mode really is and how limiting its Virtual PC-based underpinnings can be. Simply put, XP mode is a bit of a kludge, a half-baked, half-measure of a solution cobbled together from various disjointed Microsoft technologies. Compared to something like Mac OS X, which famously introduced one of the more elegant legacy compatibility solutions in the form of its integrated Mac OS 9-era application support, Windows 7's XP mode is downright homely.

Before I dive into my reasons for disliking Windows XP mode, it might be helpful to first review exactly what it is and how it works. Simply put, XP mode is a virtual machine image file that contains a fully licensed and activated copy of Windows XP with Service Pack 3 installed. The image is shipped in Microsoft's Virtual Hard Disk (VHD) format and is compatible with Windows Virtual PC 7, the company's new host-based desktop virtualization tool.

Virtual PC to the rescue Windows Virtual PC 7 is an update to the company's anemic Virtual PC 2007, a product that I panned more than a year ago in a four-way shoot-out with VMware Workstation, Parallels Workstation, and VirtualBox. The new version adds much-needed USB device support, and it claims improved performance and better integration with host system hardware resources, such as smart card readers.

Getting started with XP mode is remarkably straightforward. The first step is to install Windows Virtual PC 7 by downloading and executing its corresponding Windows Update package from Microsoft's Web site. Next, you install the Virtual Windows XP package, which copies over the necessary VHD components and registers the VM with Windows Virtual PC 7.