What Is Cloud Computing?Cloud computing is a style of computing in which data and software is housed in remote data centers rather than on-site server, which are typically accessed through the Internet. It implies that instead of running software applications on your computer, you run the apps in the "clouds" in cyberspace, in other words through the Internet. All your programs and files are stored on an outsourced computer network.Users need not have knowledge of, expertise in, or control over the technology infrastructure "in the cloud" that supports them.
The concept incorporates infrastructure as a service (IaaS), platform as a service (PaaS) and software as a service (SaaS) as well as Web 2.0 and other recent technology trends that have the common theme of reliance on the Internet for satisfying the computing needs of the users. Examples of SaaS vendors include SAP Business ByDesign, Salesforce.com and Google Apps which provide common business applications online that are accessed from a web browser, while the software and data are stored on the servers.
Cloud computing should not be confused with grid computing ("a form of distributed computing whereby a 'super and virtual computer' is composed of a cluster of networked, loosely-coupled computers, acting in concert to perform very large tasks"), utility computing (the "packaging of computing resources, such as computation and storage, as a metered service similar to a traditional public utility such as electricity") and autonomic computing ("computer systems capable of self-management").
Advantages of Cloud Computing:
1.Cost is greatly reduced and capital expenditure is converted to operationalexpenditure. Server equipment cost is reduced due to elimination of the necessity of on site servers. Staffing cost also comes down, since there is little or no need for on-site network administration.
2. This lowers barriers to entry, as infrastructure is typically provided by a third-party and does not need to be purchased for one-time or infrequent intensive computing.
3.Device and location independence enable users to access systems using a web browserregardless of their location or what device they are using, e.g., PC, mobile. As infrastructure is off-site (typically provided by a third-party) and accessed via the Internet the users can connect from anywhere.
4.Multi-tenancy enables sharing of resources and costs among a large pool of users who can acces it through PC, netbooks, mobile phones and other handheld devices.
5.Clouds provide scalability; can easily grow as the organizaton grows.
6. Security typically improves due to centralization of data, though concerns are raised about privacy issues.
Cloud Service Providers (CSPs) include bigger names like Amazon, Microsoft , Google , Sun and Yahoo.
Worldwide cloud computing services revenue is continuing to grow at a rapid rate, and is expected to top $56.3 billion (US) in 2009, according to a report from technology research firm Gartner. Market revenue grew by 21.3 per cent from 2008's $46.4 billion, and it will continue to increase to $150.1 billion in 2013.
Nonetheless, there are still concerns about security and privacy from individual through governmental level, e.g., the USA PATRIOT Act and use of national security letters and the Electronic Communications Privacy Act's Stored Communications Act.
