Buying hardware and downloading or purchasing a lot of software products and installing them and maintaining them, has been the way of using hardware and software by the users or customers. This method is product oriented.
Cloud computing changes that system. It is more service oriented than product oriented. A client wants to use a service from a service provider. It can be to use a office automation software/spreadsheet program across the internet provided service provider. But the service provider may not have any infrastructure of its own. The company may use an infrastructure provider who uses a number of resources software, hardware, applications, peripherals, networks, storage devices to offer the service. All these resources may be under what is called as a cloud.
Some part of an application may be run by one computer and another may be by another. Storage may be done on some other computer. Depending on their load and availability the various resources may be combined to offer the service to the client.
This method may increase, uptime, reduce the completion time, reliability. It exploits the different capabilities of different computers for a combined high performance.