Blue Pacific, a souped-up version of a server marketed to data-intensive businesses, was brought to Livermore in October 1998 amid a squabble over whether it would become faster than a comparable machine from Silicon Graphics located at another lab. Now fully operational, the system is churning away at its job of keeping U.S. nuclear weapons working as designed despite the cessation of testing.
Blue Pacific can perform 3.9 trillion math calculations a second, a hair shy of its goal of 4 trillion. But that's just 40 percent the speed of a planned successor, called "ASCI White." ASCI stands for Accelerated Strategic Computing Initiative, the Energy Department's plan to let computer simulations pick up where actual nuclear weapon tests left off.
All this horsepower isn't just a matter of which nuclear physicist gets bragging rights. The DOE's ASCI computers were at the heart of the debate earlier this month about whether the United States should ratify the Comprehensive Test Ban Treaty, which bans all nuclear tests.
"We are trying to take simulation and make that the major driving tool in arenas where experimentation will never be adequate," said Bruce Tartar, director of the Livermore lab. The computer simulations supplement other experiments and the "incomplete and fragmentary" data gathered from the days when nuclear tests still took place, Tartar said.
Upgrading to ASCI White
Under ASCI, the DOE has paid IBM, Intel, and SGI to come up with three cutting-edge supercomputers, built out of comparatively ordinary components and housed at the nation's three nuclear weapons labs, Lawrence Livermore, Los Alamos, and Sandia national laboratories. By the year 2004, DOE will pay for four more, the next being ASCI White.
With an estimated cost of $130 million, ASCI White will be a notch more expensive to build than the $94 million Blue Pacific. But because the Livermore lab will only lease it for two years from IBM instead of purchase it outright, it actually will cost taxpayers only $85 million, said Derrol Hammer, procurement group leader at the lab.
ASCI White will feature several improvements over Blue Pacific, including faster processors. Blue Pacific employs 5,856 PowerPC 604E chips, but the brains in ASCI White will consist of 8,192 Power3-II chips, a model that uses IBM's copper interconnect technology. Additionally, the PowerPC 604E is only a 32-bit chip, while the Power3-II is a 64-bit design, allowing the chip to more easily handle mathematical calculations requiring high precision.
ASCI White also will use a faster switching network to exchange information from one node of the computer to the other. The current system, IBM's SP switch, can transfer data at 150 megabytes per second, but ASCI White will use a technology code-named Colony that runs at 500 megabytes per second, said Terry Heidelberg, the Livermore researcher in charge of coordinating the work between the IBM and Livermore personnel.
That data transfer speed is critical to computers that use so many processors, on which calculations are often not constrained by processor speed but by one processor waiting for information from another.
To house the ASCI White, a new building with a room the size of two basketball courts has been built at the Livermore lab. That room should start filling up with ASCI White in June of 2000, said Gilbert Weigand, DOE's deputy assistant secretary in charge of research, development, and simulation. That's about three months after the March 2000 date that IBM researchers plan to test the ASCI White computer at an IBM facility in Poughkeepsie, New York, before shipping it to California, he said.
(By way of comparison, Blue Pacific fills one side of a large room that could be an appliance showroom floor if it weren't for the roar of the cooling fans, the lack of dust, and the refrigerators sporting the IBM logo. The computer is housed within 105 cabinets connected by five miles of cable, discreetly tucked away beneath the floor.)
Although it's difficult to get software to run on a computer with thousands of processors, lab personnel are working on ways to automate the process, said Chuck Athey, leader for the system administrator group at the lab.
Storage also is a challenge. Each group of four processors in Blue Pacific has its own hard disk. Those disks, in turn, are connected by a separate IBM computer called Raven to tape storage libraries called Condor and Vulcan that together can store 62 trillion bytes of data, said Kim Cupps, who controls the storage.
The ASCI program
In total, the ASCI program accounts for about $500 million of the roughly $4.5 billion the weapons labs receive each year for their stewardship of the U.S. nuclear stockpile. That stewardship program also includes high-energy physics experiments as well as careful scrutiny of actual weapons pulled out of the stockpile.
Like the labs themselves, the computers' core mission centers on nuclear weapons research, although the systems will handle a multitude of nonmilitary projects as well. Locating previously undiscovered genes, modeling supernovas, and designing more aerodynamic trucks are some of these functions, researchers said.
Nicholas Donofrio, senior vice president of technology and manufacturing at IBM, said he was excited by the possibilities of computers powerful enough to model the real world in all its detail.
"The confluence of the computing world and the real world...is where the action is going to be," he said. "It's going to be a real hoot over the next ten years."
Even though Senate Republicans defeated an effort to ratify the treaty on October 13, President Bill Clinton reaffirmed the United States' voluntary ban on nuclear testing first ordered by predecessor George Bush.