A computer cluster is a group of linked computers, working together closely so that in many respects they form a single computer. The components of a cluster are commonly, but not always, connected to each other through fast local area networks. Clusters are usually deployed to improve performance and/or availability over that of a single computer, while typically being much more cost-effective than single computers of comparable speed or availability.Grid computing is something similar to cluster computing, it makes use of several computers connected is some way, to solve a large problem. The big difference however, is that a cluster is homogenous while grids are heterogeneous. The computers that are part of a grid can run different operating systems and have different hardware whereas the cluster computers all have the same hardware and OS. A grid can make use of spare computing power on a desktop computer while the machines in a cluster are dedicated to work as a single unit and nothing else. Grid are inherently distributed by its nature over a LAN, metropolitan or WAN. On the other hand, the computers in the cluster are normally contained in a single location or complex.Also in Clusters, all nodes are set to perform a same task, controlled and scheduled by some same application (OS)
In Grid Computing, nodes perform different tasks and may be running diffrent applications independently.
So, a Grid may also consist of several Clusters.Let us take an eg. Consider 3 colleges GEC, PCC and RIT.Now we