Windows 7 will feature a Windows XP mode that will allow applications to run in an XP virtual box so they will run without problems, but will appear as if they're running natively on Windows 7. It's a great tool for businesses and may end up killing Windows XP. But ... it's not ideal for consumers.
It's primarily for small and medium-sized businesses who have applications that won't run well on Windows 7. Using it allows those businesses to upgrade to Windows 7, but still be able to run their old XP applications ... it's a great deal -- you get the flash and productivity improvements of Windows 7, while still running Windows XP apps. And you won't have to pay extra for running XP -- it will be free.
The discovery that Windows 7 will use desktop virtualization so you can run Windows-XP-compatible applications caused almost as much excitement as the news the Windows 7 Release Candidate would ship this week and next. ... [But] while there's definite potential, I uncovered some limitations and encountered a few frustrations in this beta.
Presuming your PC does support it, which means a trip into the BIOS to enable hardware virtualization, Microsoft also recommends a minimum of 2GB RAM on the host PC and 15GB drive space for each XP instance. ... Windows 7 whirs and grinds and creates a new Start Menu group called Virtual Windows XP Applications ... I started Word 2000, and after a couple of minutes' initialization, it opened in its own window, just like a native application.
it's an acknowledgment by Microsoft that, even on a new OS, old applications must work flawlessly. It also has tremendous cost-saving potential for small and medium businesses. Businesses much like the one where I work.
At my day job, we (like nearly all of our customers) run point of sale software that has a Windows-only client. ... I'd like to install mid-range 64-bit desktops that will be able to handle new applications and peripherals over that span - while still being able to run our trusty old POS software ... [which] ran seamlessly alongside other applications.
Will you be able to install XP Mode? That depends on whether your CPU supports it. Dont assume that you can use this feature because you have a new PC with a fast, powerful processor. Windows Virtual PC, which powers XP Mode, requires hardware virtualization. In the case of Intel CPUs, that means the CPU has to include a feature called Intel VT.
If your PC is powered by a new quad-core Q8400, you cant run Windows Virtual PC. An E6600 supports VT, while an E7400 doesnt. But an E8200 includes VT support. The Intel product matrix is downright baffling.
Windows XP Mode (XPM) utilizes some key RDP (6.1+) technologies to enable seamless virtual application use in Windows 7. More specifically, Remote Applications and Application Publishing.
For those not Terminal Services wizards, these technologies may sound new. Application Publishing enables you to install an application on a client machine at least as far as the user is concerned. Shortcuts and file-type associations are set up, just as a local installation would, but when the application is invoked its started on a server somewhere within your infrastructure. The Remote Applications piece then kicks in and draws the client UI in a very convincing manner.
The problem Microsoft is dealing with is the thousands of applications written using undocumented functions, diving directly into implementation data structures without using the API, saving files in places they shouldn't (i.e. blithely saving temp files into /Program Files without using the API which returns the correct folder for temp files-- lots of video games do this), relying on specific undocumented side-effects of API functions, etc. In short, for every way something could have been done wrong, it has been done wrong sometime in Windows history.
The reason Vista is incompatible is that Microsoft finally took the plunge and changed the layout/size of those internal data structures, had to remove 16-bit support (for 64-bit CPU reasons), and started enforcing the correct permissions (no write access to Program Files) for security purposes. Many of those thousands of buggy applications can never be fixed-- the source code is gone, or the company responsible is out of business. So the XP layer helps users run those applications, while also letting Microsoft actually improve their OS in the way that Apple and Linux (systems who don't give half a whit for backwards compatibility) can.
Apple had a lot of advantages in their situation that MS does not. For one thing, they controlled all the hardware. This meant no massive effort to get drivers made for an os that is still years away.
The mac development community was much smaller, tighter knit, and connected with Apple then Window's has ever been. They supported it because Mac OS X would bring a lot of things missing in 9 that caused them a ton of headaches. There was very little in the way of custom in-house apps written for Mac, because there was very little corporate mac use period.
I can't say which is sadder, trade press abdication of responsibility, people not questioning what they're fed, or XPM itself.
There is one thing that is quite clear, however. If you want XPM now, you can get there at no cost. Go download Ubuntu or Fedora Linux, and use Xen, VMWare or any other free VMM out there with your existing Windows XP licence. You will then have the same end result as using XPM, save money, gain security, and get off the Microsoft treadmill. The choice, and the money you will save, are yours.