Microsoft has launched the beta of "XP Mode," the Windows 7 compatibility add-on that runs Windows XP applications in a virtual machine.
XP Mode followed hard on the heels of Windows 7 Release Candidate (RC), the public preview that went live just before midnight Monday.
Introduced two weeks ago, XP Mode creates a virtual environment using Virtual PC, Microsoft's client virtualisation technology, then stuffs it with a pre-activated licensed copy of Windows XP Service Pack 3 (SP3), the most-current version of the eight-year-old operating system.
When it reaches final form later this year -- it's to launch at the same time as the final of Windows 7 -- XP Mode will be included by computer makers on some new PCs, and will be a free download for owners of Windows 7 Professional, Enterprise and Ultimate, the three highest-priced editions.
But because XP Mode relies on processor-based virtualisation, not all PCs can run the add-on. Microsoft has posted instructions on its Web site that describe how to determine whether a machine is XP Mode-capable, and has included links to utilities from Intel Corp. and Advanced Micro Devices (AMD) that identify eligible processors made by those two firms.
Microsoft also offered directions on how to determine whether the PC's BIOS supports hardware virtualisation, and if it does, how to switch that on.
In XP Mode, applications for the OS can be launched from the Windows 7 desktop, and appear in Windows 7 windows, rather than in a windowed virtual machine.
Analyst reaction to the add-on, however, has been lukewarm, with criticism focusing on the fact that businesses won't want to support two operating systems on each PC.
Microsoft has competition in the virtualisation space, primarily from VMware Inc. But the smaller Parallels -- best known for its Parallels Desktop for Mac -- has joined the Windows 7 fray with an announcement last Friday that it was taking beta test applications for an unnamed.
Parallels' software will let XP users migrate their physical system to a virtual machine on Windows 7 -- something that XP Mode lacks -- and, like Microsoft's add-on, will run XP applications in Windows 7-style windows. Parallels has not set a price or a ship date for the program.