Cloud computing refers to the provision of computational resources on demand via a computer network. Users or clients can submit a task, such as word processing, to the service provider, such as Google, without actually possessing the software or hardware. The consumer's computer may contain very little software or data (perhaps a minimal operating system and web browser only), serving as little more than a display terminal connected to the Internet. Since the cloud is the underlying delivery mechanism, cloud based applications and services may support any type of software application or service in use today.
In the past, both data and software had to be stored and processed on or near the computer. The development of Local Area Networks allowed for a system in which multiple CPUs and storage devices may be organized to increase the performance of the entire system. In an extension to that concept, cloud computing fundamentally allows for a functional separation between the resources used and the user's computer, usually residing outside the local network, for example, in an remote datacenter. Consumers now routinely use data intensive applications driven by cloud technology which were previously unavailable due to cost and deployment complexity. In many companies employees and company departments are bringing a flood of consumer technology into the workplace and this raises legal compliance and security concerns for the corporation.
A common shorthand for a provided cloud computing service (or even an aggregation of all existing cloud services) is "The Cloud. An analogy to explain cloud computing is that of public utilities such as electricity, gas, and water. Just as centralized and standardized utilities frees individuals from the difficulties of generating electricity or pumping water, all of the development and maintenance tasks involved in providing the software service are performed by the service provider, giving rise to the term "software as a service". This reduces the cost to individuals, and companies. What is important to the individual user is that they 'simply work'.
The principle behind the cloud is that any computer connected to the Internet is connected to the same pool of computing power, applications, and files. Users can store and access personal files such as music, pictures, videos, and bookmarks or play games or do word processing on a remote server rather than physically carrying around a storage medium such as a DVD or thumb drive. Even those who use web-based email such as Gmail, Hotmail, Yahoo, a company owned email, or even an e-mail client program such as Outlook, Evolution, Mozilla Thunderbird or Entourage are making use of cloud email servers. Hence, desktop applications which connect to cloud email can also be considered cloud applications.
