It's not exactly rocket science to get one brand of virtual machine to run under another brand's hypervisor. I'm sure it's complicated enough, given the vendor's proclivity to make it so, but a hypervisor is looking for standard information in a virtual machine file. They vary in how they read the sequence of information in the header and how they re-construct the parts, but in the end, each is doing the same thing and it's a matter of mapping one style to the other. (The hard part was when Rosenblum deciphered the x86 instruction set and emulated precisely in software what it was doing in hardware.)

"Everything about the customer's application can run unmodified in the cloud," said Rubin, a statement I want to believe for the sake of IT managers everywhere. "The big issue becomes figuring which apps are the right ones to move to the cloud."

CloudSwitch seems to open up the tantalizing prospect that spikes in workloads in the data center can be offloaded to the cloud. The CloudSwitch isolation layer registers the IP address for the application as it runs in the data center and keeps it in play, allowing the same monitoring systems used to view it to continue that function as it runs in the cloud. The policies governing the application and the security measures assigned to it follow it into the cloud as well, in the CloudSwitch approach.

There may be some unnamed weakness to this approach, some hole you don't see until you're actually using it. But I'm intrigued that what Rubin says might be possible.

Version 2.0 is due Dec. 13, and I expect to return to this topic as that date rolls around. Meanwhile, CloudSwitch was voted "most promising" by the Up 2010 audience Monday in Burlingame, Calif., having previously been named the Launch Pad favorite at Cloud Connect a year ago and the top startup in the GigaOm Structure 10 bakeoff in June.

Rubin is a veteran of Netezza, which grew to $125 million in revenue with her as its VP of marketing. It staged a successful IPO in 2007 and was recently acquired by IBM. Whether she and the CloudSwitch team are about to do it again remains to be seen, but so far the Burlington, Mass., firm has convinced Matrix Ventures, Atlas Ventures, and Commonwealth Capital to part with $15.5 million in the hopes that they will.