The hybrid cloud, or a combination of a public cloud, such as Amazon's EC2, working with an enterprise's private cloud, figured prominently in three speakers' remarks Tuesday at the Cloud Computing Conference and Expo in Santa Clara.

Mike Feinberg, Sr. VP and general manager of EMC's Cloud Infrastructure Group, said EMC anticipates that hybrid clouds will emerge out of all the interest in public and private clouds. His talk was titled, "Partly Cloudy: The Need for Hybrid Clouds."

Many people still believe cloud computing is primarily online applications, such as Salesforce.com's CRM. But Feinberg said the availability of low-cost, high-powered computing resources that end users may access to run their workloads comes closer to what cloud computing is all about.

"I think the essence of the cloud is about lowering the barrier to access, [and lowering] capital expenditures" to data center-sized resources, he said Tuesday morning in a keynote to about 350 attendees. "Some person can do their work in the cloud, and they're going to use it to innovate," Feinberg said.

The day will soon be here when cloud computing allows a person to start a small business and gain his IT infrastructure for small daily use fees. "You can build your company for the price of two lattes. You can run your whole infrastructure on the Internet at two lattes a day."

But the more likely scenario is companies doing some of their computing in external clouds and coordinating it with what they do internally in private clouds and legacy systems that don't fit into any cloud computing scheme. Cloud computing "is not about killing legacy systems," he said.

EMC in May launched its Atmos online storage service for private clouds in the enterprise and for cloud service providers.

AT&T intends to add it to its cloud services, Feinberg said, and a private cloud user can invoke Atmos as a way of implementing tiered data. The data most likely to be used can be stored inside the corporate firewall, and data that hasn't been accessed for 30 days, or qualifies under some other rules, "can be moved by policy up into the cloud."

There, the right to access the data will be covered by the same role-based policies in Atmos as those enforced inside the corporate boundaries, he noted.

Sam Gross, VP of Global Information Technology Outsourcing at Unisys, said other catalysts for private cloud computing, and eventually the hybrid cloud, will be offerings such as the Unisys Secure Cloud Computing Solution.