Cloud computing is refers to the on-demand provision of computational resources (data, software) via a computer network is rather than from a local computer system .The Users or clients can submit a task, such as word processing, to the service provider, 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 a basic display terminal connected to the Internet. Since the cloud is  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 could 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 a remote datacenter. Consumers now routinely use data-intensive applications driven by cloud technology that 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, which raises legal compliance and security concerns for the corporation.
The term "software as a service" is sometimes used to describe programs offered through "The Cloud".
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. Centralized and standardized utilities freed individuals from the difficulties of generating electricity or pumping water. All of the development and maintenance tasks involved in doing so was alleviated. With Cloud computing, this translates to a reduced cost in software distribution to providers still using hard mediums such as DVDs. Consumer benefits are that software no longer has to be installed and is automatically updated, but savings in terms of money is yet to be seen.
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 using 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 that connect to internet-host email providers can also be considered cloud applications.

How it will work

Cloud computing utilizes the network as a means to connect the user to resources that are based in the cloud, as opposed to actually possessing them. The cloud is  may be accessed via the Internet or a company network, or both. Cloud services may be designed to work equally well with Linux, Mac, and Windows platforms. With smartphones and tablets on the rise, cloud services have changed to allow access from any device connected to the Internet, allowing mobile workers access on-the-go, as in telecommuting, and extending the reach of business services provided by outsourcing.
The service provider may pool the processing power of multiple remote computers in "the cloud" to achieve the task, such as backing up of large amounts of data, word processing, or computationally intensive work. These tasks would normally be difficult, time consuming, or expensive for an individual user or a small company to accomplish, especially with limited computing resources and funds. With cloud computing, clients require only a simple computer, such as netbooks, which were created with cloud computing in mind, or even a smartphone, with a connection to the Internet, or a company network, in order to make requests to and receive data from the cloud, hence the term "software as a service" (SaaS). Computation and storage is divided among the remote computers in order to handle large volumes of both, thus the client need not purchase expensive hardware or software to handle the task. The outcome of the processing task is returned to the client over the network, depending on the speed of the Internet connection.

The Cloud engineering

Cloud engineering is the application of a systematic, disciplined, quantifiable, and interdisciplinary approach to the ideation, conceptualization, development, operation, and maintenance of cloud computing, as well as the study and applied research of the approach, i.e., the application of engineering to cloud. It is a maturing and evolving discipline to facilitate the adoption, strategization, operationalization, industrialization, standardization, productization, commoditization, and governance of cloud solutions, leading towards a cloud ecosystem. Cloud engineering is also known as cloud service engineering.

The Cloud storage

Cloud storage is a model of networked computer data storage where data is stored on multiple virtual servers, in general hosted by third parties, rather than being hosted on dedicated servers. Hosting companies operate large data centers; and people who require their data to be hosted buy or lease storage capacity from them and use it for their storage needs. The data center operators, in the background, virtualize the resources according to the requirements of the customer and expose them as virtual servers, which the customers can themselves manage. In the physical sense, the resource may span across multiple servers.