“Cloud computing” is continuously evolving, and the terminology and concepts used to define it often need clarifying.
In cloud computing, the word cloud is used as a metaphor for “the Internet,” so the phrase cloud computing means “a type of Internet-based computing,” In the simple terms it means internet-computing or computing through internet. Cloud computing means storing and accessing data and programs over the Internet instead of ones computer’s hard drive.It is a kind of Internet-based computing that provides shared processing resources and data to computers and other devices on demand through internet.Example- When you store your photos online instead of on your home computer, or use webmail or a social networking site, you are using a “cloud computing” service.
Cloud Computing uses the internet and central remote servers to maintain data and applications. Cloud computing allows consumers and businesses to use applications without installation and access their personal files at any computer with internet access. This technology allows for much more efficient computing by centralizing data storage, processing and bandwidth.It is considered the evolution of a variety of technologies that have come together to change an organizations’ approach for building their IT infrastructure. Actually, there is nothing new in any of the technologies that are used in the cloud computing where most of these technologies have been known for ages. It is all about making them all accessible to the masses under the name of cloud computing. Cloud is not simply the latest term for the Internet, though the Internet is a necessary foundation for the cloud, the cloud is something more than the Internet. The cloud is where you go to use technology when you need it, for as long as you need it. You do not install anything on your desktop, and you do not pay for the technology when you are not using it.Cloud computing is therefore a type of computing that relies on sharing a pool of physical and/or virtual resources, rather than deploying local or personal hardware and software. It is somewhat synonymous with the term ‘utility computing’ as users are able to tap into a supply of computing resource rather than manage the equipment needed to generate it themselves.
Characteristics of Cloud
On-demand self-service: A service consumer can automatically make use of the computing capabilities, such as server processing time and network storage without requiring human interaction with each service’s provider
Broad network access: Cloud Capabilities are available over the network and accessed through standard mechanisms that promote use by heterogeneous thin or thick client platforms such as mobile phones, laptops and PDAs
Resource pooling: The provider’s computing resources are pooled together to serve multiple consumers using multiple-tenant model, with different physical and virtual resources dynamically assigned and reassigned according to consumer demand. The resource include others storage, processing, memory, network bandwidth, virtual machines and email services. The pooling together of the resource builds economies of scale.
Rapid elasticity: Capabilities can be rapidly and elastically provisioned; it can be quickly scaled out, and quickly scaled in. For the user, the capabilities available for provisioning appear to be unlimited and can be purchased in any quantity at any time.
Shared Infrastructure : Uses a virtualized software model, enabling the sharing of physical services, storage, and networking capabilities. The cloud infrastructure, regardless of deployment model, seeks to make the most of the available infrastructure across a number of users.
Network Access: Needs to be accessed across the internet from a broad range of devices such as PCs, laptops, and mobile devices, using standards-based APIs (for example, ones based on HTTP). Deployments of services in the cloud include everything from using business applications to the latest application on the newest smartphones.