Grid Computing and Cloud Computing: SETI (Search for Extraterrestrial Intelligence) @Home project,

A well-known grid computing project is the SETI (Search for Extraterrestrial Intelligence) @Home project, SETI@home in which PC users worldwide donate unused processor cycles to help the search for signs of extraterrestrial life by analyzing signals coming from outer space.

The project relies on individual users to volunteer to allow the project to harness the unused processing power of the user's computer. This method saves the project both money and resources.
Grid computing does require special software that is unique to the computing project for which the grid is being used.

To do this, cloud computing networks large groups of servers, usually those with low-cost consumer PC technology, with specialized connections to spread data-processing chores across them. This shared IT infrastructure contains large pools of systems that are linked together.  Often, virtualization techniques are used to maximize the power of cloud computing.

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