Microsoft is pushing desktop virtualization 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-virtualization boom? Probably not, most experts agree.
That said, though, there will likely be an uptick in the acceptance of desktop virtualization, 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 virtualization -- but nowadays most users won't do without them.
"Improvements in the user experience are really a big deal in making desktop virtualization 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 plug-ins, 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.
Your guide to desktop virtualization
"Desktop virtualization" isn't a specific technology or even a single delivery method. It's a broad description that includes all the ways it's possible to use a desktop, laptop or other device to access data or applications that live somewhere else.
Usually that means a user with a PC interacting with an application that's running on a server in the data center. But there are a lot of ways to make that happen. According to a survey conducted by Enterprise Management Associates, most companies that implement virtual desktops do so using several different delivery methods.
Virtual applications
* Web application -- Browser interface for an application running on a server. Not what you usually think of as "desktop virtualization," Web apps do fit the definition and are tied for the most common method of delivery.
* Remote viewing -- Typically described as "application virtualization," this method allows users to view and control an app from their desktops, though the application itself runs on a back-end server. Most often a user logs into an app that many use at once; less often, a user launches a separate instance of the application for herself.
* Streaming application -- The application lives on a network server, and when a user launches it, portions of the application stream down to the user's PC to be executed locally. Takes advantage of PC-based memory and processing power, but puts greater load on the network than remote viewing.
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 aging 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 Ionia, Mich.-based 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 customization 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 labor-saving IT tactics, Mann says.
This may explain why desktop virtualization 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 virtualization 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 virtualization 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 organizations 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 off-putting to independent-minded workers -- make up a constituency of what vendors now hope will be a rush to new desktop virtualization 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.
Virtual desktop
* Remote computing -- Similar to remote-viewed applications, but the entire operating system runs on the server. The user's PC, which may be a dumb terminal with no processing capability of its own, serves only to send keystrokes and mouse clicks to the server. Users log in to a shared instance of the OS, which can support far more users per server than alternatives.
* Virtual Desktop Infrastructure (VDI) -- This term is sometimes applied to shared-desktop models, or streaming models, but more typically means that users log in to a server-based virtual machine (VM) running an operating system and applications accessible to only one user at a time. Applications that can't be used in shared systems are usually fine running in standalone VMs, but giving each end user a separate VM drastically cuts the number any given server can support.
* Streaming desktop -- Similar to streaming applications, when the user logs in, relevant portions of the operating system and applications download across the network into a virtual machine inside the user's PC. The OS and applications function there just as if they were on a standalone PC, but are isolated from the rest of the computer by the virtual machine.
* Disconnected virtual desktop -- As with a streaming desktop, the OS and applications execute within a virtual machine on the user's PC, but the VM includes caching capabilities that allow the user to operate while disconnected from the network. The VM keeps the OS and application isolated from the rest of the machine, and syncs data back to the network upon reconnection.
* Mobile virtual desktop -- Hypervisors designed for iPhones and other mobile devices can create virtual machines within which some OS and application code can execute. More commonly, they allow portable devices to become viewing platforms (similar to dumb terminals) for server-based virtual desktops or applications.
Still, the appeal is there for some customers. Virtualizing a Windows 7 migration gives IT a lot more control by keeping the whole process inside the data center 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 virtualization, 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-virtualization product manager doesn't sound comfortable with the idea that most or all of a major company's PCs could be virtualized.
"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 virtualization technology.
While Microsoft is "excited to have an offering" in the virtual desktop market, the company believes customers "should virtualize 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.
Savings can be tricky to calculate
Further, Microsoft's Woodgate worries that companies can overestimate their potential cost savings with virtual desktops because they don't add the cost of gearing up the data center to support it.
"You're replacing the hard drive of a laptop, which is about the cheapest memory there is, with space in a Storage Area Network, which is about the most expensive memory there is," Woodgate adds.
On that point, Woodgate and Winburn disagree. Server- or SAN-based storage is secure, backed up, cheaper to maintain and far more rarely lost, broken or abused than a laptop, Winburn says.
And, Thornton says, even looking just at hardware costs, virtual desktops saved his organization about $100 per machine. The district wound up using the free XenServer rather than VMware's vSphere on the servers as was the original plan.
"With a thin client and Linux OS on it, half a gig of RAM, a little Atom processor, license for XenDesktop, plus the cost of a server divided by 30 -- we figured we could get 30 VMs per server -- we came up with about $550 per unit," Thornton explains. "Compare that to $650 to $700 for a regular PC. Thin clients have no moving parts, they're built to resist heat. We figure they'll last eight or 10 years, compared to three or four Gartner recommends for a PC. That raises the savings even more."
In zeroing in on cost as a crucial element in the virtualization decision process, Thornton and Winburn agree with the majority of IT shops. Indeed, Mann's survey at EMA showed that three quarters of companies interested in desktop virtualization primarily wanted to save on hardware and administration costs, and half expected to save on software.
That contrasts with server-based desktop virtualization, in which 70% of respondents said flexibility and agility -- the ability to add or reduce computing power, the ability to launch as many "new" virtual PCs as necessary at a moment's notice and the ability to give users access to "their" PC image or files no matter where they work -- was the main reason to switch.
Schools' big savings