What is cloud computing?

Gartner defines cloud computing as “a style of computing in which massively scalable IT-related capabilities are provided ‘as a service’ using Internet technologies to multiple external customers.” Beyond the Gartner definition, clouds are marked by self-service interfaces that let customers acquire resources at any time and get rid of them the instant they are no longer needed.

The cloud is not really a technology by itself. Rather, it is an approach to building IT services that harnesses the rapidly increasing horsepower of servers as well as virtualization technologies that combine many servers into large computing pools and divide single servers into multiple virtual machines that can be spun up and powered down at will.

What is a public cloud?

Naturally, a public cloud is a service that anyone can tap into with a network connection and a credit card. “Public clouds are shared infrastructures with pay-as-you-go economics,” explains Forrester analyst James Staten in an April report. “Public clouds are easily accessible, multitenant virtualized infrastructures that are managed via a self-service portal.”

 What is a private cloud?

A private cloud attempts to mimic the delivery models of public cloud vendors but does so entirely within the firewall for the benefit of an enterprise’s users. A private cloud would be highly virtualized, stringing together mass quantities of IT infrastructure into one or a few easily managed logical resource pools.

Is cloud computing the same as software-as-a-service?

You might say software-as-a-service kicked off the whole push toward cloud computing by demonstrating that IT services could be easily made available over the Web. While SaaS vendors originally did not use the word cloud to describe their offerings, analysts now consider SaaS to be one of several subsets of the cloud computing market.

What types of services are available via the cloud computing model?

Public cloud services are breaking down into three broad categories: software-as-a-service, infrastructure-as-a-service, and platform-as-a-service. SaaS is well known and consists of software applications delivered over the Web. Infrastructure-as-a-service refers to remotely accessible server and storage capacity, while platform-as-a-service is a compute-and-software platform that lets developers build and deploy Web applications on a hosted infrastructure.

 What types of applications can run in the cloud?

Technically, you can put any application in the cloud. But that doesn’t mean it’s a good idea. For example, there’s little reason to run a desktop disk defragmentation or systems analysis tool in the cloud, because you want the application sitting on the desktop, dedicated to the system with little to no latency.