Quoting Australian IT

A new information technology discipline is emerging around application delivery to control desktop management costs and security over a widening array of devices.

Under the broad banner of Virtual Desktop Infrastructure (VDI), images of operating systems or application code are being dynamically streamed to devices, accessed remotely or served up as Web 2.0 pages.

Wrapped around these are service-level guarantees for specific applications encompassing network performance and application response times for different locations.

Gartner research director Martin Gilliland says Citrix is leading the charge but faces competition from Softricity, which has been acquired by Microsoft, and from AppStream.

"The next generation of delivery is application streaming," Gilliland says.

"The key reason why they developed different models is because remote display protocols, such as with Citrix or Windows Terminal Services, don't suit every purpose."

Application streaming serves program code to terminal or desktop machines, often with its own cut-down virtual operating system.

Citrix Access Gateway product manager Sandler Rubin says this means his company's Presentation Server can run a Windows Vista application on an XP machine, or conflicting versions of software.

"Four years ago Citrix was about server-based computing," Rubin says. "Now we've become much more sophisticated and nuanced."

Michael Kleef, a technology adviser at Microsoft, says his company supports choice, such as application streaming into isolated environments, or even remote desktops each running on their own server blade.

Another variation on the theme is to run multiple virtual machines on the same desktop.

Kleef points to the usefulness of application streaming as providing a centrally managed isolation chamber for troublesome applications.

"With streaming, in terms of performance, you get it on the local machine," Kleef says.

Of course, simply dragging operating systems or applications from a file server was popular in the early 1990s, even to diskless workstations.

This fell out of fashion because of growing download sizes over limited bandwidth.

Gigabit ethernet overcomes this problem, but Rubin says application delivery is different from file serving.

For example, VDI can maintain a security context between users and devices and pick the right delivery mechanism. It also encompasses service-level guarantees for wide area network response times.

This need has propelled Citrix into the hardware acceleration business, where it now powers sites such as Google and Yahoo.

All these pieces are subject to centralised policy management, which is what Access Gateway provides.

"When you speak to a CIO, they take for granted that the network will work," Rubin says.

"What worries them is how they will bring their applications out to branch offices.

"You need to focus how you deliver the applications."

Citrix says it has "joined hands" with Hewlett-Packard, IBM, Microsoft, SAP and Oracle to raise the awareness of application delivery as a strategic technology approach.

Oracle Australia-New Zealand technology sales vice-president Robert Gosling says this is necessary to take advantage of his company's grid computing capabilities, so applications can spread across the grid on-demand and extra servers can be plugged in as needed. All this application support could be wasted without guaranteed delivery to users.

"There's a demand from the business to have service-level arrangements for the delivery of applications," Gosling says.

"The idea that you can take a system down for two hours overnight to give it a patch is disappearing. They want consistent response times under different workloads and to deliver new applications at a reasonable cost and timeframe."

Rubin likens these early days of application delivery to the time when departmental LANs were joined up to create one centralised network.

Likewise, using multiple systems run by different people over different business units to deliver applications is inefficient, he argues.

Kleef says the new techniques are "no silver bullet".

He and Gilliland point to sales people still needing traditional PC support for their notebooks.

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