Microsoft is pushing desktop virtualisation as a way of making Windows 7 play nicely with old applications, especially those written for Windows XP. So now that the technology has been "blessed" by Microsoft, can the industry brace for a desktop virtualisation boom? Probably not, most experts agree.

That said, though, there will likely be an uptick in the acceptance of desktop virtualisation, for a couple of reasons. First, more vendors are offering Virtual Desktop Infrastructures (VDI), which give each end user a private "desktop." VDI uses the same kind of hypervisors that allow many virtual machines to run on a single physical host. But rather than running five- or ten-server VMs on one physical server, VDI can run 50 PC operating systems, each of which serves a single end user.

The other big change is support for peripherals, multimedia and other web- and PC-focused technologies. These have been inaccessible for users of shared-image terminal services types of systems, that is traditional desktop virtualisation, but nowadays most users won't do without them.

"Improvements in the user experience are really a big deal in making desktop virtualisation more acceptable," says Andi Mann, an analyst with Enterprise Management Associates.

Giving end users all the benefits and all the capabilities they'd have on standalone machines, including the ability to add or update their own browser plugins, media players and other "extraneous" software, could overcome most of the objections by business units that have kept virtual desktops out of the mainstream user base, Mann says.

Extending the life of an old PC

Another element that may make virtual desktops far more popular is the unwillingness of some companies to upgrade their PC hardware enough to support migrations to Windows 7, according to Chris Wolf, infrastructure analyst at The Burton Group.

Implementing Windows 7 requires upgrading hardware, updating custom built software, training end users and updating the security on PCs with the new OS. That process can be so expensive and disruptive that many companies are asking consultants like The Burton Group to evaluate whether it makes sense to leave end users on their present hardware and upgrade them by running Windows 7 as part of a virtual desktop connection, Wolf explains.

Connecting end users to a new OS on the server can more than double the life of an ageing PC, while still giving end users all the power and support for new software and new technology they want, according to Peter Graves, CIO of Independent Bank.

Because about 90% of his bank's users already use shared session virtual desktops from Citrix Systems, adding the other 10% is no great leap once the technology supports the software customisation and peripherals they need, Graves says.

The same is not true of most companies, many of which have little history or understanding of virtual desktops and are just getting used to virtual servers, cloud computing and cost- and labour-saving IT tactics, Mann says.

This may explain why desktop virtualisation has been around for at least a decade, but it has yet to take off. IT managers have told analysts and pollsters that they're ready to adopt virtual desktops but have not yet made the leap.

"All the surveys we and others have done of end users showed a tremendous interest in desktop virtualisation that just hasn't happened yet in the marketplace," Mann says. "We've been looking for a sharp inflection in sales of virtual desktops for three years", but it hasn't taken place.

A survey of end user companies that Enterprise Management Associates released in September shows the top three barriers to desktop virtualisation are all human factors, based either on users' ignorance of the technology or politics about who has control over it.

Windows 7's role

Banks, hospitals, schools, government agencies and other organisations that have either very tight budgets or restrictive operating regulations have made up the bulk of Citrix' and Wyse Technology's installed base for years.

Other companies, which have resisted terminal services-based virtual desktops as too clunky, too restrictive and too offputting to independent minded workers make up a constituency of what vendors now hope will be a rush to new desktop virtualisation products, Burton Group's Wolf says.

There's nothing that requires all those potential virtual desktops to run on Windows, let alone Windows 7, Wolf acknowledges. While running virtual Windows 7 desktops would be cheaper than the real thing, it's still not as cheap as the virtual XP desktops companies may already be running.

Still, the appeal is there for some customers. Virtualising a Windows 7 migration gives IT a lot more control by keeping the whole process inside the data centre and by reducing the hardware and support costs as well, Wolf says.

That might make two big migrations more attractive than just one, at least that's what Microsoft, Citrix and a host of third-party developers are hoping, he says.

Microsoft's dilemma

For its part, Microsoft seems to be playing both sides of the issue. The vendor is clearly supporting desktop virtualisation, but is leery of anything that would threaten the primacy of the standalone PC as the main business computing platform.

Even Microsoft's main desktop virtualisation product manager doesn't sound comfortable with the idea that most or all of a major company's PCs could be virtualised.

"We expect to see a significant amount of deployment [of virtual desktops] on Windows 7 from CIOs looking for reduced costs in deploying applications on Windows 7," says Scott Woodgate, the director of Windows product management who is leading development of Microsoft's desktop virtualisation technology.

While Microsoft is "excited to have an offering" in the virtual desktop market, the company believes customers "should virtualise for the right reasons, for the flexibility it offers, not just focus on the potential cost savings," Woodgate says.

Windows 7 itself should save money compared to Vista for its better management, security and stability as well as because it takes up less disk space than Vista, he says. This in turn could save costs in VDI implementations that involve hundreds or thousands of instances of the OS running in separate VMs, Woodgate explains.

On the negative side, Woodgate says, VDI implementations are more complex to configure than more standard PC-based networks. VDI networks require administrators to create virtual machines, permissions and policies governing how the VMs behave and the images from which VMs are launched, in addition to configuring and managing a standard PC network.

Some users agree with Woodgate's assessment about complexity. George Thornton, network operations manager for Texas' Montgomery Independent School District, and Landon Winburn, Citrix administrator for the University of Texas Medical Branch, a medical school, said that planning virtual desktop rollouts can be intimidating to IT groups that are just getting started.

Figuring out which of several delivery methods is most effective for specific types of users is difficult, as is creating just a few "golden" OS images most users can launch as "their" desktop, rather than try to keep a different one for each user, Thornton says.