Cloud Computing,” to put it simply, means “Internet Computing.” The Internet is commonly visualized as clouds; hence the term “cloud computing” for computation done through the Internet. With Cloud Computing users can access database resources via the Internet from anywhere, for as long as they need, without worrying about any maintenance or management of actual resources. Besides, databases in cloud are very dynamic and scalable. Cloud computing is unlike grid computing, utility computing, or autonomic computing. In fact, it is a very independent platform in terms of computing. The best Example of cloud computing is Google Apps where any application can be accessed using a browser and it can be deployed on thousands of computer through the Internet.


Cloud computing provides the facility to access shared resources and common infrastructure, offering services on demand over the network to perform operations that meet changing business needs. The location of physical resources and devices being accessed are typically not known to the end user. It also provides facilities for users to develop, deploy and manage their applications ‘on the cloud’, which entails virtualization of resources that maintains and manages itself. Some generic examples include:
• Amazon’s Elastic Computing Cloud (EC2) offering computational services that enable people to use CPU cycles without buying more computers
• Storage services such as those provided by Amazon’s Simple Storage Service (S3)
• Companies like Nirvanix allowing organizations to store data and documents without adding a single on-site server
• SaaS companies like delivering CRM services, so clients can manage customer information without installing specialized software

Cloud computing can be categorized into three parts:
1. Platform as a Service (PaaS)
2. Infrastructure as a Service (IaaS)
3. Software as a Service (SaaS)