It's a well-known fact that the SETI@home distributed computing program is the largest grid computing effort in the world, with 4.7 million computing nodes. But do you know how many people work to maintain this network? The SETI team manages 1 ‰ of the world's total computing capacity with only six programmers and system administrators, according to this interview with David Anderson, the project leader for the SETI@home program, by Astrobiology Magazine. In other words, each member of the team is handling about 800,000 PCs. Impressive, isn't?
Here are some excerpts from this interview. Let's start with the beginning of this distributed computing project.
In the 80s and early 90s there was a gradual transition from a situation where computers were busy most or all of the time -- like shared mainframes, or early slow PCs that labored to keep up with basic tasks -- to a situation where they were almost never busy. Typing 90 words per minute at Microsoft Word uses less than 1% of even a slow Pentium chip. Economy of scale led to microprocessors getting faster at a greater rate than "big" computers, and in the 90's they took the lead. Almost every "supercomputer" built since then has been based on Pentium-type chips.
But Anderson recognizes that some supercomputing problems need something different from a grid.
There's a huge spectrum of supercomputing problems. Some of them require frequent, high-bandwidth communication between processors. For these, supercomputers (like the IBM Accelerated Strategic Computing Initiative, ASCI, series) will always be best.
"Public distributed computing" (my name for what SETI@home does) only works when the data-to-computing ratio is low, and high latencies are tolerable.
Anderson also notes that the volunteers who donate computing time do it not only to search for extraterrestrial life, but for social reasons.
The "top users" leader board has always been dominated by organizations (e.g. computer companies) that own lots of computers and run them all under the same account. For this reason, teams became the focus of competition; it gives every user a chance to belong to a "top 10" entity.
Teams have also played a role in adoption -- team members recruit new users to boost their team's standings.
Finally, Anderson gives some details about the Berkeley Open Infrastructure for Network Computing, BOINC, which is designed to allow other science projects to access the unique SETI@home architecture.
Q: Can you speak about your plans for rolling out BOINC? In particular the possibilities with biology such as protein folding and gene mapping or climate prediction. Any others that have been suggested?
There's another project involving gravity-wave detection and LIGO. [Two completely independent gravity detectors located in Washington State and Louisiana, the Laser Interferometer Gravitational-Wave Observatory (LIGO) is essentially a giant strain gauge, designed to detect gravity waves for the first time].
I'm personally extremely excited about the possibilities of BOINC, both for scientists (who now have a chance to do previously unfeasible computations) and the public (who will soon have a smorgasbord of projects available to them).
Source: Astrobiology Magazine, January 12, 2004