Cluster computing is loosely defined as at least two computers connected together to cooperatively share a processing load. As a result, the cluster seems like a single entity, and the grouping of computers may be referred to as a cluster machine. The computers are usually joined by a shared communications network, e.g. local area network.
One advantage of cluster computing is that it may provide performance advantages over a single computer. Another advantage of a cluster computing is that it may be readily adapted to perform parallel processing.
An extension of the cluster computing concept is grid computing where the computers may be farther apart on a given network, e.g. the Internet, than in a traditional cluster machine. Additionally, the computers in a grid computing system may be more informally linked to one another than in a grid computing system.