The Grid, as proposed, defined and pioneered by Ian Foster and Karl Cesselman in 1998, was introduced as an exciting, and very promising new way to meet computational demands of complicated scientific applications without the need for big mainframes and supercomputers, but instead utilizing existing, off-the-shelf hardware. Ian Foster defined the Grid as:

“a hardware and software infrastructure that allows for pervasive, dependable, consistent and inexpensive access to high-end computational capabilities and large-scale cross-organizational resource sharing in a heterogeneous distributed environment.”

The notion of resource in this definition goes beyond raw computational cycles: secondary storage; physical and virtual memory; file systems; communication links; applications; printers; back end databases; specialized hardware like vector computers; specialized software; and many more that could potentially be utilized in a Grid environment.

Think of the World Wide Web (WWW): an application built on the Internet infrastructure, that allows sharing of information. Well, the Grid can be though of as the WWW where instead of information, we can share resources!

The term may well refer to the electrical power grid -where you just plug in your device and you immediately have as much power as needed by that device. The main theme behind the Grid concept is pretty much the same: you plug in your computer into the Grid, and you can immediately utilize any resources required by the applications running in your machine transparently and efficiently.

1. Distributed Resource Discovery and Allocation
2. Distributed Data Management
3. Efficient Service/Component Composition to produce Higher Level Components
4. Scalability in Grid Systems
5. Adaptability to environmental and application changes
6. Failure Resilience, Check-pointing and Migration
7. Multiple administrative and security domains require special techniques for:
   
   • Accounting
     
   • User Management
     
   • Access Control
     
   • Auditing
     
   • Single sign-on mechanisms
     
   • Delegation of rights and credential proxies
     
   • and more…
8. Coordinated Resource Access and Scheduling
9. Suitable Tools and programming environments
10. Suitable programming model
11. many, many more…

1. http://www-130.ibm.com/developerworks/  Plenty of introductory articles and tutorials in the Grid section
2. http://gridcafe.web.cern.ch/gridcafe  Excellent introduction using plain English!
3. http://www.ggf.org  The Global Grid Forum is an international Grid community and standards organization

1. F. Berman, A. Hey and G. Fox, Eds., Grid Computing: Making the Global Infrastructure a Reality. John Wiley & Sons, 2003.
   
   
2. I. Foster, C. Kesselman and S. Tuecke, “The Anatomy of the Grid: Enabling Scalable Virtual Organizations,” International Journal of Supercomputer Applications, vol. 15. pp 200-222, 2001.
   
   
3. I. Foster and C. Kesselman, Eds., The Grid II: Blueprint for a New Computing Infrastructure, Morgan Kaufmann, 2003.
   
   
4. I. Foster, C. Kesselman, S. Tuecke and J. Nick, “The Physiology of the Grid: An Open Grid Services Architecture for Distributed Systems Integration,” Open Grid Service Infrastructure WG, Global Grid Forum, 2002.