“Cloud computing is a phrase used to describe a variety of computing concepts that involve a large number of computers connected through a real-time communication network such as the Internet. In science, cloud computing is a synonym for distributed computing over a network, and means the ability to run a program or application on many connected computers at the same time. The phrase also more commonly refers to network-based services, which appear to be provided by real server hardware, and are in fact served up by virtual hardware, simulated by software running on one or more real machines. Such virtual servers do not physically exist and can therefore be moved around and scaled up (or down) on the fly without affecting the end user – arguably, rather like a cloud.”— From wiki
In the simplest terms,Cloud is a infrastructure for the Internet,cloud computing is a type of computing which based on Internet and a type of computing that relies on sharing computing resources rather than having local servers or personal devices to handle applications. Instead of traditionally hardware-stand local storage, cloud computing makes us to store and access data and applications over the Internet.
Cloud computing is offered in different forms: public clouds,private clouds,and hybrid clouds,which combine both public and private.And it’s services are broadly divided into three types:Infrastructure-as-a-Service(IaaS),Platform-as-a-Services(PaaS) and Software-as-a-Service(SaaS).