Grids for different needs
Different people need grids for different reasons. There are all sorts of grids already operating all around you.
• National grids are hosted by one country. Such grids are useful in emergency situations, such as earthquakes or terrorist attacks. National grids can also support scientific investigations, such as studies of climate change, space station design and environmental cleanup.
• Project grids are created to work on a specific goal. They are typically contructed from shared resources for a limited time and are designed to meet the needs of multi-institutional research groups and "virtual teams". The LHC Computing Grid (LCG) is an example of a project grid; it was set up to help with the Large Hadron Collider high energy physics experiment.
• Private grids are sometimes called local grids or intra-grids, and are used by institutions such as hospitals and corporations. These grids are relatively small and centrally managed.
• Goodwill grids are created when volunteers donate their spare computer capacity to a good cause. When you are not using your computer, a "goodwill grid" project can use it instead. Examples include the "@home" projects, where your computer can help solve some of the world's biggest questions.
• Peer-to-peer grids rely on a "give to get" philosophy, where users exchangeg data with other users. The now defunct Napster is an example of old peer-to-peer technology that required a central control (which is how Napster got nailed!); however, newer versions are truly peer-to-peer, requiring no third-party intervention.
• Cloud-like grids allow users to rent extra computing power by paying the computer owners. Examples are services offered by Amazon or Google.