Wearing his Stanford University associate professor of computer science hat, and flanked by peers from cloud-computing pioneers Amazon.com, Google Inc. and Salesforce.com, Rosenblum defined cloud computing simply as an environment where "your software is running software somewhere else than your data center."
At the same time, virtualization is a "building block" of cloud computing, Rosenblum said, and also "a natural evolution," stemming from the way the technology decouples software from the underlying hardware, and enables workloads, or virtual machines, to move around between systems.
"You just have to feel comfortable with someone else running your software," he added. But, if enterprises' continued use of mainframes is any indication, that's a big caveat, Rosenblum suggested.
"It still stuns me that the IBM mainframe that everyone said is dead is still kicking," Rosenblum said. Even today, enterprises continue to buy mainframes and "load 30-year old software" on them. Why do they do that? "Because [they] know it works," he said. When it comes to the cloud, those enterprise IT managers are doubtlessly asking themselves, "How complex is it? How stable is it?" Sure, someday, "the cloud may be more reliable than I can run [my servers], but then the question is – when will we reach that point?"
Google's product management director and fellow panelist Matthew Glotzbach, meanwhile, painted a picture of users becoming increasingly divorced from considerations about underlying technology.
"For the average IT guy, the level of abstraction keeps moving up a level," said Glotzbach. "With the cloud, barriers to integration between two systems fall away. … People care less and less about the specifics."
Rosenblum concurred that, at the low level, moving virtual machines around between cloud providers is probably easy enough, but that higher up the stack, moving data between application providers was another story. Turning to Salesforce.com Executive Vice President of Technology Parker Harris, Rosenblum said "I'm assuming that jumping from Salesforce.com to another CRM [customer relationship management] vendor wouldn't be as simple."
"Once you use a service, you get lock-in," Harris concurred.
Alex Barrett reporting.