Most of the people think Grid Computing and Cloud computing are same, but they are totally different. Both grid and cloud computing are networks which abstract processing tasks. Abstraction masks the actual complex processes taking place within a system, and presents a user with a simplified interface with which they can interact easily. The idea is to be able to make the system more user-friendly.
What is cloud computing?
In simple Cloud computing is sharing of resources by many users, for example imagine a company which had been formed recently with physical infrastructure such as buildings and computers, they cant spend further money on software. Thus they come towards cloud where they have to pay only for the resources which they are using, it helps them to save money.
What is grid computing?
Grid in other hand is a combination of resources from different domains. They are the true Distributed Systems, a supercomputer is a good example of a Grid computation where it follows a path to get the required resources unlike the cloud. What this means is that your grid-enabled application is not tied to the computer on your desk, it can seamlessly use more than one computer and other resources even beyond the walls of your building to boost its performance.
Real Difference between Grid and Cloud?
So what’s making cloud so special when compared to Grid, the answer is simple. When an application fails in one node, the other application on the other node may also fail, thus bringing the problem of availability in Grid. A Cloud would usually use a grid. A grid is not necessarily a cloud or part of a cloud. Thus they are two different identity with nearly common goals.