This cloud model has been dubbed RaaS (resource as a service) by Technion-Israel Institute of Technology researchers Orna Agmon Ben-Yehuda, Muli Ben-Yehuda, Assaf Schuster and Dan Tsafrir, who wrote a on the topic that will be presented at next week's USENIX HotCloud '12 conference in Boston.

The concept of owning computing resources has gradually been worn down over time, they write in the paper. "Before cloud computing, the average useful lifetime of a purchased server was approximately three years. With the advent of web-hosting, clients could rent a server on a monthly basis," they said. The subsequent rise of services like Amazon's Elastic Compute Cloud (EC2) drove the equation down to hours.

But the hourly-rental model won't be sufficient as the cloud market matures, the researchers argue.

"If you pay for a full hour or any part of it, you will waste half an hour on average over the lifetime of every virtual machine," the paper states. "If you only pay for a full second or any part of it, then you will only waste half a second over the lifetime of every virtual machine."

Some cloud providers have already begun selling sub-hour chunks, the researchers note, and other IaaS conventions, namely fixed bundles of compute power, memory and networking resources, are "starting to unravel," the paper adds.