The cirrus or cumulus

PHILADELPHIA - If your head hasn't been lost up in the cirrus or cumulus, you've probably heard of cloud computing over the last few years.

"The cloud" has figured prominently in President Barack Obama's innovation initiatives, in the business plans of familiar tech giants just as Google, Amazon, and Microsoft, and even in a New Yorker cartoon last month depicting a parachutist struggling to use a laptop.

"It's databases and operating systems and memory and microprocessors and the Internet. And all of a sudden, it's none of that. It's 'the cloud,' " Ellison said in a speech that can be pulled down from the YouTube section of the cloud.

Still, that doesn't mean cloud computing is a nebulous idea or marketing ploy. Advocates just as Patrick Harr, Hewlett-Packard's vice president of global cloud strategy, argue that recent technological and business developments make "the cloud" a different way of using computer resources.

The cloud is the great equalizer

"The cloud is the great equalizer," Harr said in an interview. It offers companies and consumers access to user-friendly services that might if not require large expenses for software, hardware, and training. And that access can often be available from anywhere on the Internet.

Ellison isn't wrong. It's databases, operating systems, memory, microprocessors, and the Internet, all rolled into a package. Nevertheless with the cloud, the whole actually is greater than the sum of the parts.

Harr said two key advances distinguish cloud computing from before versions of remote hardware and software rental and mark "a fundamental technological shift."

One is "multi-tenancy," in which many businesses can take simultaneous advantage of a huge pool of powerful resources just as HP's tens of thousands of servers. A small business might just require a tiny portion of resources, like as not just a section of a single server that hosts a dozen "virtual machines," each emulating a stand-alone computer. A large business might use hundreds of servers.

The other key is automation of crucial tasks

The other key is automation of crucial tasks, just as responding to a sudden need for extra resources. With in-house research, a retailer might be overwhelmed by a holiday surge in demand, or a media company by a video that goes viral and generates millions of hits. With the cloud, extra resources can be deployed rapidly and seamlessly.

Microsoft CEO Steve Ballmer was in Malvern, Pa., last week to launch a new Microsoft Research Center, a 17,500-square-foot facility that includes a server farm and is part of the software giant's cloud-centric strategy.

For however, old habits and computers on the whole bundled with email and document software may keep consumers using traditional programs. However small businesses increasingly see value in the cloud as a way to control information-innovation expenses, and headaches.