For quite some time now, the prevailing wisdom has put the relatively low uptake of virtual desktop infrastructure (VDI) on security fears and user resistance, despite the substantial cost savings to be had.

But now it seems that a third factor was in play, at least in the eyes of those who hope to profit from VDI: the pending release of Windows 7.

According to Computerworld's Jon Brodkin, the thinking goes like this: Why bother spending serious coin on a virtual desktop platform when in a few months we'll simply have to migrate all those instances to a new operating system? After all, simply shifting from a physical to a virtual platform is bad enough without having to throw in a Vista/XP-to-Windows 7 conversion into the process.

Microsoft, of course, is not shy about playing up the VDI capabilities of its new OS. Just before the official release, the company came out with an updated Desktop Optimization pack chock full of virtual goodies. Among them are the Enterprise Desktop Virtualization (MED-V) module that allows you to place virtual desktops on top of Windows 7 and throws in a number of server-based management controls for client-side provisioning and delivery of VDI images. There is also the Application Virtualization (App-V) module that allows for client or remote management of Windows server applications.

But while Microsoft is likely to gain both from the early enthusiasm for Windows 7 and its close ties with VDI provider Citrix and its own Hyper-V hypervisor, it seems that VMware is being equally aggressive in pointing out 7's benefits for VDI. The company has added Windows 7 support in its newest VMware Workstation 7, complete with features like Flip 3D and Aero Peek, as well as the improved graphics, multicore support and support for leading development platforms like the SpringSource Tools Suite and Eclipse IDE.

While Microsoft and VMware may have their differences, in this case, VMware support is probably welcomed since it sends a major headache to another key rival: Apple. With Windows 7 on board, VMware is also touting the newest version (3.0) of VMware Fusion, which allows 7 to boot up on the Mac. While Apple still holds the keys as to where Mac OS X can be run (which is to say, nowhere but Macs), the new Fusion at least allows W7 and Snow Leopard to run side by side, giving more Mac users a taste of how the rest of the world lives and works.

Will it draw more Mac users into the Windows fold? Probably not. Mac fans are a dedicated bunch, and it probably will take more than a new OS to overcome years of hostility toward what they consider a poorly engineered environment.

But for both Microsoft and VMware, that's not the big prize anyway. There's much more leverage to be gained by getting in on the ground floor of the desktop virtualization wave.

And now that the OS migration can proceed on the physical layer first, it makes the decision to go virtual that much easier.