Windows 7 comes with a new feature called ‘Windows XP Mode.’ This feature just RTM’d (Released to Manufacturing) on October 1st and is now available for Download on MSDN or Technet. It will be freely available to all owners of a Windows 7 Professional license on October 22nd.

Windows XP Mode is a feature that allows Windows XP applications to run on Windows 7 if they cannot otherwise run natively on Windows 7.

Windows XP Mode relies on Windows Virtual PC to be installed. This is currently a 10mb download on MSDN or Technet and is labeled ‘mu_windows_virtual_pc_x64_435190.msu’ for x64 machines (an x86 version is available too). A key requirement for Windows Virtual PC is for Virtualization to be enabled in the BIOS (not available on older CPU’s).

Some of the enhancements of Windows Virtual PC over Virtual PC 2007 is USB support and the ‘auto publish feature.’ The auto publish feature allows for any program’s shortcut that is dragged to the virtual machine’s start menu to appear on the host machine’s start menu, so that when it is launched on the host machine, the application actually starts up from within the guest/child virtual machine.

Basically, Microsoft is giving you a free copy of Windows XP to run inside Windows 7 in order to eliminate any reasons from not upgrading to Windows 7. A small 400mb installation of XP is available for free from owners of the Windows 7 Professional license (and higher versions). When I decompressed it, it expanded to about 1.2GB.

For example, While Windows 7 ships with Internet Explorer 8, there are some older browser-based applications that still require Internet Explorer 6. This is a good example where Windows XP mode comes in handy. In my testing, Internet Explorer 6 started up in 6 seconds when the virtual machine was in hibernation state.After closing Internet Explorer, the virtual machine does not automatically hibernate. Instead it stays running in the background for a while, so that you can start the application back up again even faster. On subsequent attempts, IE6 started in less than one second. Bravo Microsoft! This is really fantastic.

One downside to XP mode is it does not allow you to be in full screen mode while at the same time opening XP mode applications on the host. For example, while you can startup XP Mode in full screen to interact with the desktop and install applications, it must be shut down before you can actually launch those applications from Windows 7. Another drawback that used to exist in Virtual PC 2007 is the drag and drop feature between the parent and child virtual machine. But perhaps the biggest disappointment with Windows Virtual PC is the inability to run x64 child operating systems.

One recommendation I have after installing XP Mode is to install an anti-virus product. You need to treat each virtual machine just like it were a separate physical computer and ensure that it is configured as securely as you would configure a physical computer. Microsoft recently released a free anti-virus product for consumers called Security Essentials. You can download it for free here.

In the enterprise, organizations that wish to prevent XP mode can disable in with Group Policy. An example why they might consider this is to force adoption of the big-brother to XP mode, ‘MEDV’ – Microsoft Enterprise Desktop Virtualization. Basically, it is like a centrally managed XP mode that IT can deploy virtual machines running applications that are not otherwise compatible with Windows 7. MEDV requires Software Assurance but is an awesome product.

There are other options for application remediation other than XP mode and MEDV, including Microsoft’s Application Compatibility Toolkit.

If you multiple desktops, say for example in a lab environment, you can now consolidate them into a virtual environment easily without having to install System Center Virtual Machine Manager. Sysinternals released a free copy of Disk2Vhd, allowing you to P2V (Physical to Virtual conversion) a physical system so that it can run as a virtual machine in your Windows Virtual PC. Pretty cool! It can be downloaded for free here.