Grid VS Cluster

Grid computing is where you have separate administrative domains over a wide area, machines used by different people trying to cooperate.

Clustering is where you have a set of machines in one place, and you're trying to get them look like a single machine.

There are different aspects from the user's standpoint when they run their jobs, from the administration side when you do things like update the software.

The grid refers to a parallel and distributed system with *distributed* resource management , whereas a cluster hascentralised resource management.
Usually, a Grid would be composed of nodes that are themselves clusters.

Think of a cluster as a 'local' concept, and a grid as a 'global' concept...

Now I could understand the difference between the grid and cluster to some extent, what about you?