Cloud computing is Internet-based computing, whereby shared resources, software and information are provided to computers and other devices on-demand, like the electricity grid. It is a paradigm shift following the shift from mainframe to client–server that preceded it in the early 1980s. Details are abstracted from the users who no longer have need of expertise in, or control over the technology infrastructure “in the cloud” that supports them. Cloud computing describes a new supplement, consumption and delivery model for IT services based on the Internet, and it typically involves the provision of dynamically scalable and often virtualized resources as a service over the Internet.It is a byproduct and consequence of the ease-of-access to remote computing sites provided by the Internet.
The term “cloud” is used as a metaphor for the Internet, based on the cloud drawing used in the past to represent the telephone network, and later to depict the Internet in computer network diagrams as an abstraction of the underlying infrastructure it represents. Typical cloud computing providers deliver common business applications online which are accessed from another web service or software like a web browser, while the software and data are stored on servers.
Most cloud computing infrastructure consists of reliable services delivered through data centers and built on servers. Clouds often appear as single points of access for all consumers’ computing needs. Commercial offerings are generally expected to meet quality of service (QoS) requirements of customers and typically offer SLAs. The major cloud vendors include the largest IT vendors: Google, IBM, Microsoft, and HP along with Amazon and VMWare. /MSNU