Monday, February 19, 2007

Grid computing

How much do you use your computer?

No, I mean, like really use it?

What proportion of your CPU cycles are doing any real work? If you are anything like me, not terribly many. The "Idle" process on Windows XP runs at around 60-70%, even when I think I'm busy. I suppose the computer might get a bit more of a hammering if you are regularly playing graphics-intensive games, or videos.

There are ways that your computer can do more useful things. The first example of this (not counting the infamous XEAGLE Delta function) was my father-in-law deciding not to switch his computer off, but using it overnight to calculate pi to (I think) 100,000 decimal places - it may have been more: I forget.

The process of downloading Debian Linux - two DVD's worth - about 9 GB - introduced me to BitTorrent - a means of distributed downloading, which in addition to spreading the download across however many computers had copies (or partial copies!) of the target download, incorporated my computer into the network for uploading as well - so my computer was able to help reduce the load, and hence the wait times, on other servers. Neat!

Finally, there is proper grid computing - a means of doing lots of computing by using the spare processing power on home computers. Today, I downloaded software from, which means that my computers at home can be used for a large project to evaluate candidate molecules as anti-cancer drugs. Here is a description of the project:
The United Devices Cancer Research Project will advance research to uncover new cancer drugs through the combination of chemistry, computers, specialized software, and organizations and individuals who are committed to fighting cancer.

The research centers on proteins that have been determined to be a possible target for cancer therapy. Through a process called "virtual screening", special analysis software will identify molecules that interact with these proteins, and will determine which of the molecular candidates has a high likelihood of being developed into a drug. The process is similar to finding the right key to open a special lock — by looking at millions upon millions of molecular keys.

Participants in the United Devices Cancer Research Project are sent a ligand library over the Internet. Their PC will analyze the molecules using a docking software called LigandFit by Accelrys. The LigandFit software analyzes the molecular data by using a three-dimensional model to attempt to interact with a protein binding site. When a ligand docks successfully with a protein the resulting interaction is scored and the interactions that generate the highest scores are recorded and filed for further evaluation.
There are many other distributed computing projects. Here's a list on Wikipedia. So why's your computer sitting around doing nothing?