What is Grid Computing and what are its benefits?

Alternatively we have Grid Computing, which is well defined by Mary Humphrey and Mary R. Thomson: “A Computational Grid is a collection of heterogeneous computers and resources spread across multiple administrative domains
with the intend of providing users easy access to these resources.”

Ian Foster made a three point checklist to define what a
Grid is. In this list he said:

•“coordinates resources that are not subject to centralized control” : Which means that not only one entity manages all the system but some different system administrators could be managing different parts of the same Grid at the same time.
•“using standards, open, general-purpose protocols and interfaces” :This will allow to all the companies involved in the Grid to use and access these standards.
•“to deliver nontrivial qualities of service” :In Grid computing not a fixed rate of load is going to be managed and this can be given small or big rates. This phenomenon causes the given quality of service to vary and not always stay constant. Grids allow the use of idle resources. Through this, companies create a Grid in order to share those idle resources and, if necessary, they can access more computational resources(shared by other companies) than they usually can, and share their own resources while they are not carrying out any computationally demanding tasks.