If there was one big trend in 2008 -- and by that we mean the buzz phrase on the lips of every analyst and vendor -- it was cloud computing. As with all new IT trends, levels of adoption were low. But adoption of what, exactly? The most interesting thing about cloud computing is that arguments over its definition continue to rage even as customers pay actual money for it.
In April, InfoWorld offered its definition of cloud computing, which turned out to be one of the most popular stories we've ever run. (That a 950-word definition could get so much traffic speaks volumes about the level of confusion over the cloud.) We tried to keep it simple: "Cloud computing encompasses any subscription-based or pay-per-use service that, in real time over the Internet, extends IT's existing capabilities."
[ Confused about the cloud? Check out InfoWorld's quick and easy definition in "What cloud computing really means." ]
We broke cloud services into seven categories. You could easily reduce that to three: infrastructure services such as Amazon EC2; software as a service à la Salesforce; and development platforms as a service (Microsoft Azure now offers the prime example). Those are the most important service groupings, although it's worth checking out the original article to get the complete picture.
So where's the controversy? Well, on the one hand, some folks insist that cloud computing refers to infrastructure services alone, which is basically the utility computing model. Instead of buying new servers, you move virtual machines to a service provider over the Internet -- period. We see that as an unnecessarily narrow view and prefer to include SaaS and its ilk. To us, it's all about computing services, apps included, that you procure outside rather than inside enterprise.
On the other hand, some big vendors such as IBM go even broader and talk about the "internal cloud." Yes, they say, cloud services on the Internet are cloud computing, but with the right infrastructure, IT departments can deliver their capabilities to internal customers as cloud services, too. To enable that scenario, this view aggregates other IT trends, such as SOA (service-oriented architecture), virtualization, datacenter automation, and EDA (event-driven architecture) into one harmonious internal cloud.
That's a lot of technology to swallow in one gulp -- and the notion of some sort of self-running IT nirvana is easy to ridicule. But the vendors have a point: Why shouldn't internal IT resources packaged and delivered as services qualify as cloud computing? If IT can pull it off, then the internal cloud has the same contours as the external cloud.
[ Amazon actually offers three overlapping services: EC2, S3, and Simple DB. Contributor Rich Grehan breaks it all down in "Diving deep into Amazon Web Services." ]