The makings of a do-it-yourself supercomputer

Making a supercomputer these days is a lot easier than you might think. I even helped build one myself in just one day earlier this month.

The call to create the processing beast came from a group of University of San Francisco graduate students whose goal was to entice hundreds of computer enthusiasts like myself to unite their laptop and desktop systems into a megacomputer powerful enough to crack the list of the Top 500 fastest supercomputers on Earth. Topping that list is Japan's 40-teraflop Earth Simulator.

Armed with my 2.4-GHz Pentium 4 Compaq notebook, I joined roughly 300 people at the USF gym where we were put to work building the so-called Flashmob1 supercomputer.

Overnight, staff and students had transformed the gym into a massive data center. Neat bundles of Ethernet cables lined the edges of the rows of tables that filled the gym. The cables trailed from four Foundry Networks switches that were positioned around the room. An imposing platform stood in the middle of the gym where lecturers and a few students would sit and monitor Flashmob1's beating heart.

After checking our computers with the security monitors at the gym's entrance, each volunteer was given directions to the table that would house their particular speed of machine. "A Pentium 4?" asked my security monitor with a nod of approval. "Go to the back of the room."

There, a hub captain, who was dressed in the staff uniform of a black T-shirt with the Flashmob1 logo, helped me set up my machine. I told him I'd brought my power pack. "Good, you'll need it," he said. "If your laptop ran on battery, it'll last just 10 minutes calculating this benchmark."

He booted up a CD that contained all the software that my machine would run that day. "A supercomputer on a disk" was how it was described by Pat Miller, a computer scientist at the Lawrence Livermore National Laboratory in Livermore, Calif., and a USF lecturer.

Miller seemed relaxed considering he was expecting 1,400 machines to turn up. A system with that many nodes would boast 600 gigaflops of processing power - enough to crunch the benchmark that all Top 500 hopefuls need to run in less than four hours, and put our Flashmob1 supercomputer at the bottom of the next Top 500 list that's published in June.

It was Miller's do-it-yourself supercomputing class that sparked the idea of Flashmob Computing. Inspired by "flashmobs," a recent craze of organizing a group of strangers to turn up at a given place to do something off-the-wall, like singing a song, and then disperse once the deed is done, the students wanted to invite volunteers to donate their machines for the day.

The task was enormous. "The limiting factor is memory size [of the nodes]," Miller said. I thought about my laptop's 512M-byte memory capacity. "We're taking in a lot of boxes, and some could randomly break . . . there could be bad network cables. We're beating on the memory very fast, and the processor would be working all the time." If one of the computers failed during the benchmark, then Flashmob1 would collapse.