The definition of cloud computing has been rather elusive. Some CEO’s like, Larry Elison are frustrated because they claim that their sofrware already runs on the cloud. Others, like the the slash dot rhino herd has made this cloud computing definition post one of the most popular of last year:

“Even though IBM’s Irving Wladawsky Berger reports a leading analyst as having said recently that ‘There is a clear consensus that there is no real consensus on what cloud computing is,’ here are no fewer than twenty attempts at a definition of the infrastructural paradigm shift that is sweeping across the Enterprise IT world — some of them really quite good. From the article: ‘Cloud computing is…the user-friendly version of grid computing.’ (Trevor Doerksen) and ‘Cloud computing really is accessing resources and services needed to perform functions with dynamically changing needs. An application or service developer requests access from the cloud rather than a specific endpoint or named resource.’ (Kevin Hartig)”

But this month, the Electrical Engineering and Computer Sciences University of California at Berkeley has put a highly acclaimed paper together on the cloud: Above the Clouds: A Berkeley View of Cloud Computing.

We uploaded it here also: Above the Clouds: A Berkeley View of Cloud Computing - a 25 page pdf document.

Here is how Berkely sees it: 

Cloud Computing refers to both the applications delivered as services over the Internet and the hardware and systems software in the datacenters that provide those services.

The services themselves have long been referred to as Software as a Service (SaaS).

The datacenter hardware and software is what we will call a Cloud. When a Cloud is made available in a pay-as-you-go manner to the general public, we call it a Public Cloud; the service being sold is Utility Computing.

We use the term Private Cloud to refer to internal datacenters of a business or other organization, not made available to the general public.

Thus, Cloud Computing is the sum of SaaS and Utility Computing, but does not include Private Clouds.

The paper is great - it is interesting to read, has some great quotes and it lists opportunities and the current top 10 obstacles to cloud computing.  Highly recommended.