In the five months that I have been researching and writing Cloud Computing Bible, it has become clear to me that most people recognize that cloud computing is a big deal, even if they are not really clear why that is so. Every day newspaper and magazine articles and radio and TV stories report on cloud computing. The phrase “in the cloud” has entered into our colloquial language. You may have heard that the United States government has initiated a “cloud initiative,” or that nearly 75 percent of the developers at Microsoft are currently working on “cloud-related” products, or that a phone or service stores its data in the cloud. The cloud is therefore this amorphous entity that is supposed to represent the future of modern computing.

In reality, the cloud is something that you have been using for a long time now; it is the Internet, along with all the associated standards and protocols that provide a set of Web services to you. When you draw the Internet as a cloud, you are representing one of the essential characteristics of cloud computing: abstraction. In the cloud, resources are pooled and partitioned as needed, and communications are standards-based.

The Internet was begun as a network of networks, with an architecture that was redundant and could survive massive disruption. What the original system architects of the Internet could not have anticipated is that the size of resources attached to it would become massively scalable, which is the second characteristic of cloud computing.

Google's infrastructure, for example, which is described in this book in Chapter 9, spans 30 datacenters around the world with over a million computers; infrastructure that Google now leases out to developers upon which applications may be staged. So the third and equally as important characteristic of cloud computing is that the cloud is a “utility” and that services are provided using a pay-as-you-go model.

A computing utility has been a dream of computer scientists and industry luminaries for several decades. With a utility model of computing, an application can start small and grow to be enormous overnight. This democratization of computing means that any application has the potential to scale, and that even the smallest seed planted in the cloud may be a giant.