Cloud computing is the use of computing resources (hardware and software) that are delivered as a service over a network (typically the Internet). Cloud Computing Architecture
Cloud computing is Web based computing that allows businesses and individuals to consume computing resources such as virtual machines, databases, processing, memory, services, storage, or event number of calls or events and pay-as-you-go.
The pay-as-you-go model charges for the resources as much as you use. Unlike traditional computing, if you do not use any resources, you do not pay. It is similar to having a water connection or an electricity line. You have a meter and meter keeps track of your monthly usage and you pay for that usage at a given rate.
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cloud computing means storing and accessing data and programs over the Internet instead of your computer's hard drive. The cloud is just a metaphor for the Internet