Could someone explain what is cloud computing please?

http://blogs.discovery.com/good_idea/Could someone explain what is cloud computing please?
The article you linked has a pointer to the Wikipedia entry for cloud computing at http://en.wikipedia.org/wiki/Cloud_compu鈥?/a>



The term "cloud" is synonymous with Internet. It comes from the days when we first had computers at one location - such as a bank's main office - sending and receiving data from computers at another location - such as a bank's branch office - using the Internet to bridge the two. Since nobody really knew the exact amount of firewall, router and other equipment involved and exact path of the data communication (which might change as one part gets congested with too much data traffic) within the Internet itself, it was just represented as a big, fluffy cloud with communications going into the cloud and coming out. At that time, we weren't interested in keeping data on machines in the Internet (i.e., in the cloud). Rather, we just passed data through the cloud to machines that we under our control.



Cloud computing then, is when we are passing data to and from a local machine (under our control) from and to a machine located somewhere in the Internet that is not under our control. It's likely that you are already using cloud computing.



If you have a gmail (or hotmail or yahoo) mail account, you read, reply and create your email on a computer in front of you. The cloud part comes in when you consider that when you read an email, you are just looking at a local copy of an email. The original is on a Google mail server - somewhere out there. When you create a new email and send it, the mail is stored on a Google mail server and then sent on to the recipient. Where is this server? What brand is it? How much disk space does it have? You don't know, really. What's more, you don't care. Rather than mail being an application on your computer (such as Microsoft Outlook) and having your email stored as files on your computer, you use a browser (which is an application in its own right) to access an web-based service (Gmail) for your email. Facebook, Myspace and Google Apps are other examples of cloud computing which are already available. Your data is on computers you don't own, touch, or see, but instead you use the cloud computer's services to create, view, edit and even delete it.



That is the crux of "cloud computing." Functions you used to do by installing applications onto a computer under your control and then creating or copying files onto that computer (email, word processing, spreadsheets, song libraries, etc.) you now access as services using applications on a computer you probably don't even know the location of let alone what hardware is in it. Your data is somewhere on those "cloud computers."