Cloud computing or cloud computing is an infrastructure in which computing power and storage are managed by remote servers to which users connect via a secure Internet link. Desktop or laptop computers, mobile phones, touch pads and other connected objects become access points for running applications or viewing data that is hosted on servers. The cloud is also characterized by its flexibility, which allows providers to automatically adapt storage capacity and computing power to user needs.
There are several types of cloud services:
IaaS (Infrastructure as a Service, in English): the operating system and applications are installed by clients on servers to which they connect to work as if it were a regular computer.
PaaS (Platform as a Service, in English): in this mode, the cloud service provider administers the operating system and its tools. The customer can install his own applications if needed.
SaaS (Software as a Service): Applications are delivered as turnkey services to which users connect through dedicated software or a web browser. For the general public, this is for example electronic messaging such as Gmail, Yahoo, Outlook.com or office suites such as Office 365 or Google Apps.