Eventually we’ll have the intercloud, the cloud of clouds. This intercloud will have the dimensions of one machine comprised of all servers and attendant cloudbooks on the planet.
When I first wrote about cloud computing way back in 2008 [see IEEE Spectrum, August 2008], there was a gee-whiz aura surrounding this relatively new way of storing our data and provisioning computing resources. Now, more than eight years later, cloud computing is just another humdrum piece of technology. For proof, you need look no further than the latest version of Gartner’s famous Hype Cycle for Emerging Technologies, which no longer includes an entry for “Cloud Computing,” a sure sign of mainstream acceptance. But network engineers have not been idle—they’ve been busy inventing new subsets of cloud computing. These new subtypes must have new names, of course, and so the lexicon of cloud computing has changed quite a bit over the last eight years.
There’s a growing field of cloud-related inventions with names that play on their “cloud” origins. For example, fog computing refers to data storage, applications, processing, and other computing services delivered from nearby devices rather than from a remote data center (after all, fog is what we call clouds that come close enough to touch). If you push some of these cloud-oriented services to the client devices themselves, the services are now “on the ground,” so to speak, and they become dew computing.
Since in a typical network diagram the cloud sits at the center and the devices that access it reside at the end points—or the edge, as engineers would say—the networks where much of the processing is pushed to these endpoints are known as edge computing. If the network is designed with cellular and other mobile devices in mind, then it’s called mobile-edge computing, and the scaled-down data centers at the edge of the network are known as cloudlets. If the network enables a connected mobile device to seamlessly switch from one of these microclouds [PDF] to another, the entire system is called a follow-me cloud [PDF]. More generally, in the same way that a network of networks has long been known as an internet, such a cloud of clouds is called an intercloud.
Almost all of us now run around with a personal cloud, which refers to all the data, apps, and services that get synchronized, streamed, and shared across our devices. That content now goes through giant data centers owned and operated by corporations that are doing who-knows-what with our information. But what if the content was held by people you know? That’s at least part of the promise behind social cloud computing, which combines the trust inherent in social networks with the services provided by cloud computing. The social cloud eschews the data center in favor of a cloud infrastructure made up of millions of individual PCs, a system known as peer-to-peer cloud computing. This ad hoc cloud [PDF] is possible only if enough people donate their idle computer resources, a system known as volunteer cloud computing. It’s an example of distributed cloud computing [PDF], where the network infrastructure resides across multiple small data centers that are geographically dispersed. If you bump up the distribution from individual PCs to organizations that have common interests and concerns, then you’ve got yourself a community cloud. If those organizations are communications service providers, then you can call it a carrier cloud.
How can you tell when a new term has become a part of mainstream language? One sign is that the word can be used outside of its originating context without having to be defined. The term cloud certainly passes this test, even though computing experts would be hard-pressed to come up with a watertight definition. Another sign is seeing the term used as a metaphor. Give cloud a check mark here as well. For example, there’s the notion of the human cloud, which refers to the independent workers that a company, using online sites or apps, can hire temporarily to perform tasks as needed. Similarly, your friend cloud refers to all your Facebook connections. In a few short years, cloud has gone from pie-in-the-sky to can’t-live-without-it. Clouds, it seems, have nothing but sunny days ahead.
This article appears in the December 2016 print issue as “Cloud Computing Is Raining Metaphors.”