Microsoft’s acquisition of Calista Technologies may bring little more than an improved remote display protocol, but indicates that the Redmond giant has its eye on a new market.

The virtualisation sector is booming. Analysts estimate that market leader VMware is on track for revenue of $1.5bn (£770m) this year. And IDC predicts that global spending on the technology will jump from $6.5bn (£3.3bn) in 2006 to $15bn (£7.7bn) by 2011.

Until now, Microsoft has lagged behind. But with last week’s purchase of Calista and its partnership with thin client specialist Citrix, the software giant is gearing up to take on VMware.

And by talking up virtualisation now, it hopes to persuade customers considering large-scale migrations to Windows Vista to look at the hosted desktop model as an alternative, according to Gartner vice president Brian Gammage.

“It gives IT managers the option of doing things differently ­ centralising the desktop environment rather than going out and touching the entire PC installed base,” he said.

“It allows them to avoid getting their hands dirty at the operating system level.”

The timing of the Calista deal also coincides with the launch of Microsoft’s server virtualisation platform. HyperV technology is expected next month as part of the upgraded Windows Server 2008 operating system.

“In the long term, Microsoft believes in the broad application of virtualisation on every desktop PC,” said Gammage.

“But that requires changes in the Windows licensing model that it is not ready to make.”