From slide rule to supercomputer: Scientists have gone from mechanical calculations to petaflops in just decades

ImageWhen Bruce Harmon, senior scientist for the Ames Laboratory, attended Lane Technical High School in Chicago, slide rules were the uniform for scientists and engineers.

“You were a nerd if you wore your slide rule on your hip,” Harmon remembers. “So I never wore mine on my hip because I didn’t want to look too nerdy.”

By the time he graduated, simple calculators that could add numbers electronically were just beginning to be available. “They were primitive. I could beat them with my slide rule most of the time,” he said.

When Harmon joined the Ames Laboratory as a post-doctoral worker in the 1973, computing as a tool in scientific research was beginning to take hold. In his office today, he keeps a stack of computer punch cards as well as a shelf of magnetic data tapes, as reminders of how computing has evolved as a problem-solving tool for scientists.

Just decades later, Harmon and fellow Department of Energy scientists are accessing the power of supercomputers like Titan, located at the DOE’s Oak Ridge National Laboratory in Oak Ridge, Tenn., capable of processing calculations in petaflops, or 1015 calculations per second. For Harmon and other Ames Laboratory scientists, it’s a tool to analyze crystal structures and discover new material alloys.

“It’s on a scale that’s hard for people to grasp,” said Harmon. “Imagine every man woman and child on the planet, doing one calculation in one second. That’s six gigaflops and you can get that on your desk top right now. Let’s ask the whole planet to do 1000 calculations in one second. That is six teraflops. Now let’s have them doing a million calculations in one second. That’s six petaflops. And we’re already well past that in supercomputing.”

The calculations for his own doctoral thesis, completed 40 years ago, he estimates could be done in 15 minutes today.

 “Really, it’s been like a miracle,” said Harmon, reflecting on the growth of computational power. “You could think of some scientific problem way too difficult, and ten years later the computers would open a door that you could go through, and begin tackling the solution.” That is still going on he said, as the Dept. of Energy works towards a goal of computers capable of processing in exaflops, or 1018  calculations per second.