Imagine several million computers, including desktops, laptops, supercomputers, data vaults, and instruments such as meteorological sensors and telescopes. These computers are all over the world and belong to many different people.

Now imagine that you connect all of these computers in to a single, huge and super-powerful computer. Wow! This huge, sprawling, global computer is what many people dream "The Grid" will be.

WHAT IF THIS DREAM CAME TRUE?

If you are a scientist, and you want to run a colleague's molecular simulation program, you would no longer need to install the program on your machine. Instead, you could just ask the Grid to run it remotely on your colleague's computer. Or if your colleague's computer was busy, you could ask the Grid to copy the program to another computer that was sitting idle somewhere on the other side of the planet, and run your program there. In fact, you wouldn't need to ask the Grid anything. It would find out for you the best place to run the program, and install it there.

And if you needed to analyse a lot of data from different computers all over the world, you could ask the Grid to do this. Again, the Grid could find out where the most convenient source of the data is without you specifying anything, and do the analysis on the data wherever it is.

And if you wanted to do this analysis interactively in collaboration with several colleagues around the world, the Grid would link your computers up so it felt like you were all on a local network. This would happen without you having to worry about lots of special passwords, the Grid could figure out who should be able to take part in this common activity.

So much for the dream; what about the reality?