IBM to retake 'fastest computer' title

ASCI Purple will be used to simulate nuclear explosions in 3-D
　
Scientists will soon be able to observe the first instants after a nuclear warhead detonates. Fortunately, it will be a three-dimensional simulation, made possible by the world's fastest computer. IBM and the U.S. Department of Energy announced Tuesday the sale of a $290 million supercomputer, capable of performing 100 trillion calculations per second. Armed with that much computing firepower, a 3-D simulation of the first one-millionth of a second in a nuclear explosion will take eight weeks to calculate.

　
　

ASCI PURPLE, as the massive computer will be called, has a sobering task. Working at Lawrence Livermore National Laboratories, the hefty computer will be dedicated to the task of monitoring the nation's nuclear missile stockpile.
Every year, the Department of Energy has to certify to the U.S. president that the missiles are safe and in working order. Computers are constantly running simulations to predict the likelihood of missile failure in a war, or the consequences of a missile mishap while still in peacetime.

Currently, the former world's No. 1 computer, ASCI White, did the job. But it can only run simulations on simple theoretical models, said lab spokesman David Schwoegler. ASCI Purple will do the first true-to-life, three-dimensional simulation of a detonation.

And testing the nuclear arsenal requires much more than simulating the behavior of the plutonium inside a bomb. In fact, everything inside the bomb must be tested because materials tend to act in unpredictable ways during a detonation. One thing the computer will be able to test, for example, is whether aging materials hold potential hazards.

In the process, the computer will also help scientists unmask some of the 20th century's great mysteries. Nuclear weapons, Schwoegler said, were built in the past "pragmatically, not scientifically." In other words - the bombs worked, but the scientists building them were basing their construction on theories, instead of observation.

"I've seen scientists look at materials calculations on ASCI White and say, I knew that happened, but I couldn't prove it," Schwoegler said.

ASCI Purple is as fast as 50,000 top-of-the-line PCs performing calculations simultaneously. Its operating memory is 400,000 times greater than that of the average PC, and it can store data equivalent to the U.S. Library of Congress - 30 times over. At 100 teraflops - or 100 trillion calculations per second - it will be about eight times faster than its predecessor, ASCI White, and about three times faster than the world's current No. 1 computer, The Earth Simulator in Yokohama, Japan. That NEC-built machine was installed earlier this year, knocking IBM out of the top spot.

THE POWER OF THE HUMAN BRAIN
Hans Moravec, a professor at Carnegie Mellon University's Robotics Institute, says ASCI Purple represents an important milestone for the computing industry. Twenty years ago, he predicted that computers would require 100 terraflops of calculating power to simulate the activity of the human brain. Right on the schedule he predicted, that milestone has been reached.

"It seemed astronomically large back then," Moravec said. In fact, his predictions were first published in a science fiction magazine. "I'm glad somebody remembered." Moravec's approximation is based on some observed facts - namely, the amount of computing power required to simulate the activity of the retina, which is about 1 billion calculations per second. For an approximation, he then calculated that the retina is about 1/100,000th the size of the entire brain. So he simply multiplied 1 billion times 100,000.

The real trick for the industry, however, is to get the cost of ASCI Purple sized-computing power down from $290 million to about $1,000. At that point, he said, there will be robots which can act more or less like people. That kind of cost reduction might again sound like science fiction, but don't be fooled, said Moravec."I expect that in about 2020," he said.