20-06-2011, 09:58 AM
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Cloud computing
History has a funny way of repeating itself, or so they say. But it may come as some surprise to find this old cliché applies just as much to the history of computers as to wars, revolutions, and kings and queens. For the last three decades, one trend in computing has been loud and clear: big, centralized, mainframe systems have been "out"; personalized, power-to-the-people, do-it-yourself PCs have been "in." Before personal computers took off in the early 1980s, if your company needed sales or payroll figures calculating in a hurry, you'd most likely have bought in specialized "data-processing" services from another company, with its own expensive computer systems, that specialized in number crunching; these days, you can do the job just as easily on your desktop with off-the-shelf software. Or can you? In a striking throwback to the 1970s, many companies are finding, once again, that buying in computer services makes more business sense than do-it-yourself. This new trend is called cloud computing and, not surprisingly, it's linked to the Internet's inexorable rise. What is cloud computing? How does it work? Let's take a closer look!
Photo: Cloud computing: the hardware, software, and applications you're using may be anywhere up in the "cloud." As long as it all does what you want, you don't need to worry where it is or how it works. Composite photo by Explainthatstuff.com based on a picture of an IBM Blue Gene/P supercomputer, by courtesy of Argonne National Laboratory, published under a Creative Commons Licence, and a cloud photo by Brian Ferguson courtesy of US Air Force.
What is cloud computing?
Cloud computing means that instead of all the computer hardware and software you're using sitting on your desktop, or somewhere inside your company's network, it's provided for you as a service by another company and accessed over the Internet, usually in a completely seamless way. Exactly where the hardware and software is located and how it all works doesn't matter to you, the user—it's just somewhere up in the nebulous "cloud" that the Internet represents.
Cloud computing is a buzzword that means different things to different people. For some, it's just another way of describing IT (information technology) "outsourcing"; others use it to mean any computing service provided over the Internet or a similar network; and some define it as any bought-in computer service you use that sits outside your firewall. However we define cloud computing, there's no doubt it makes most sense when we stop talking about abstract definitions and look at some simple, real examples—so let's do just that.
Simple examples of cloud computing
Most of us use cloud computing all day long without realizing it. When you sit at your PC and type a query into Google, the computer on your desk isn't playing much part in finding the answers you need: it's no more than a messenger. The words you type are swiftly shuttled over the Net to one of Google's hundreds of thousands of clustered PCs, which dig out your results and send them promptly back to you. When you do a Google search, the real work in finding your answers might be done by a computer sitting in California, Dublin, Tokyo, or Beijing; you don't know—and most likely you don't care!
The same applies to Web-based email. Once upon a time, email was something you could only send and receive using a program running on your PC (sometimes called a mail client). But then Web-based services such as Hotmail came along and carried email off into the cloud. Now we're all used to the idea that emails can be stored and processed through a server in some remote part of the world, easily accessible from a Web browser, wherever we happen to be. Pushing email off into the cloud makes it supremely convenient for busy people, constantly on the move.
Preparing documents over the Net is a newer example of cloud computing. Simply log on to a web-based service such as Google Documents and you can create a document, spreadsheet, presentation, or whatever you like using Web-based software. Instead of typing your words into a program like Microsoft Word or OpenOffice, running on your computer, you're using similar software running on a PC at one of Google's world-wide data centers. Like an email drafted on Hotmail, the document you produce is stored remotely, on a Web server, so you can access it from any Internet-connected computer, anywhere in the world, any time you like. Using a Web-based service like this means you're "contracting out" or "outsourcing" some of your computing needs to a company such as Google: they pay the cost of developing the software and keeping it up-to-date and they earn back the money to do this through advertising and other paid-for services.