Cloud computing

In past few years cloud computing infiltrated computer industries, the cloud has been variously hailed as the savior of IT and reviled as a risky and chaotic environment. “The cloud” is simply a business model for the creation and delivery of compute resources. The model’s reliance on shared resources and virtualization allows cloud users to achieve levels of economy and scalability that would be difficult in a traditional data center. It is a colloquial expression used to describe a variety of different types of computing concepts that involve a large number of computers connected through a real-time communication network such as the Internet. Cloud computing relies on sharing of resources to achieve coherence and economies of scale similar to a utility (like the electricity grid) over a network. At the foundation of cloud computing is the broader concept of converged infrastructure and shared services.

Common cloud options include:

• Public cloud, in which multiple companies share physical servers and networking resources hosted in a provider’s data center.
• Private cloud, in which companies do not share resources (although efficiencies may be realized by hosting multiple virtual applications from the same company on a single physical server). Private clouds can be located either in a provider’s data center or in the company’s own on-premises data center.
• Hybrid cloud, in which virtualized applications can be moved among private and public cloud environments.

Common cloud benefits include:

• Scalable, on-demand resources: The ability to launch a cloud application in minutes, without having to purchase and configure hardware, enables enterprises to significantly cut their time to market. By taking advantage of cloud options for “bursting” during peak work periods, enterprises can also cost-effectively improve application performance and availability.
• Budget-friendly: Cloud computing services require no capital investment, instead tapping into the operating budget. As many companies tighten up their processes for approval of capital expenditures, a service can be easier and faster to approve and deploy.
• Utility pricing: The pay-per-use model that characterizes most cloud services appeals to enterprises that want to avoid overinvesting. It also can shorten the time to recoup the investment.

Few cloud computing providers:

Google	Oracle	Amazon Web Services	Microsoft
Rackspace	Salesforce	VMware	Joyent
Citrix	Bluelock	CenturyLink/Savvis	Verizon/Terremark