'

What is cloud computing?

We've been reading quite a bit about cloud computing recently.  Many find all of this chatter confusing because they really don't have a clear idea of what this is.

We've been reading quite a bit about cloud computing recently.  Many find all of this chatter confusing because they really don't have a clear idea of what this is.  To tell you the truth, I hear so many different definitions from so many different sources that I find myself confused too.

I recently received a good question from a reader who was confused about external and in-house clouds. The question can be found here: http://talkback.zdnet.com/5208-12695-0.html?forumID=1&threadID=61251&messageID=1128398. I did my best to answer the question in a reply and thought that you might be able to help this reader.

My reply

There are a number of different definitions for "cloud computing." So, what is meant by the term differs from supplier to supplier. Generally, the term refers to the availability of an application, a application framework or IT infrastructure available for use on the internet on a pay-to-play pricing structure. Often a self-service management and activation structure is in place as well.

An in-house cloud the result of the organization's IT organization adopting a similar structure for use of the organization's own infrastructure.

Application virtualization suppliers typically point out that they've developed technology that allows applications that use their technology to be run in the "clouds" somewhere as well as on the local net. Amazon's EC2 is a popular selection for these suppliers. If you'll review recent posts about moves made by DataSynapse and 3Tera you'll see some examples.

Virtual processing software companies, such as Citrix, Microsoft and VMware have all made announcements of agreements with a number of Hosting companies allowing virtual machines that typically run in an organization's own IT infrastructure to move into and out of the clouds.

Now it's your turn

What's your definition of cloud computing? How is that different from "utility computing", "hosted computing", "managed computing" and the like?