Inside the Cloud: How Cloud Computing Works
In cloud computing, a network of computers functions as a single computer to serve data and applications to users over the Internet. The network exists in the "cloud" of IP addresses that we know as the Internet, offers massive computing power and storage capability, and enables wide-scale group collaboration.
What, exactly, is this "cloud"? Put simply, the cloud is a collection of computers and servers that are publicly accessible via the Internet. This hardware is typically owned and operated by a third party in one or more data center locations. The machines can run any combination of operating systems; it's the processing power of the machines that matter, not what their desktops look like.
Individual users connect to the cloud from their own personal computers or portable devices (such as Apple's iPhone), over the Internet. To these individual users, the cloud is seen as a single application, device, or document. The hardware in the cloud (and the operating system that manages the hardware connections) is invisible.
This cloud architecture is deceptively simple, although it does require some intelligent management to connect all those computers together and assign task processing to multitudes of users. Each cloud uses various monitoring and metering functions to track usage so that resources are apportioned and attributed to the proper user(s).
This automation of management tasks is key to the notion of cloud computing. The system isn't a cloud if it requires human management to allocate processes to resources. For a system to attain cloud status, manual management must be replaced by automated processes.