Lab to sample Linux for weapons work

Los Alamos National Laboratory is buying a $6 million, 2,048-processor Linux supercomputer to see how well nuclear weapons simulation software will work on simpler computers.

Los Alamos National Laboratory is buying a $6 million, 2,048-processor Linux supercomputer to run its nuclear weapons simulation software, an effort that will test the limits of these less expensive megamachines.

The lab has been a pioneer in building inexpensive supercomputers made out of ordinary computing components and the Linux operating system. Thus far, however, LANL's nuclear weapons simulation software runs on more expensive systems from SGI and Hewlett-Packard such as HP's $215 million "Q" now under construction.

A $6 million price tag may sound like a bargain in comparison, but software must be reworked to run using less expensive clusters of Linux machines. Though the new system will run unclassified programs such as predicting the properties of new materials, those tests will serve as a proxy to predict how well nuclear weapons simulation software works, said lab spokesman Jim Danneskiold.

The lab's central mission is ensuring that U.S. nuclear weapons will work as planned, despite aging and the current ban on actual nuclear tests. LANL has software that simulates the physical effects such as the extreme pressure and intense X-rays that accompany nuclear explosions.

Intel-based supercomputers are becoming less exotic, having escaped academia and found buyers in the private sector such as Companie General de Geophysique for oil and gas exploration work and MTU Aero Engine for engine design.

The new system, called the "Science Appliance" and built by Salt Lake City-based Linux NetworX, uses a cluster of 1,024 interconnected servers, each with two 2.4GHz Intel Xeon processors. It's a close relative to another cluster at LANL's sister laboratory, Lawrence Livermore National Laboratory.

The Science Appliance, due by the end of the year, will be capable of a peak computational speed of 10 trillion calculations per second, Linux NetworX said. The computing nodes will be stacked 50 to a rack, with 27 racks taking up a patch of floor space about 18 by 25 feet. The nodes are connected with a high-speed switch from Myricom.

There are future expansion options in the LANL deal, said Clark Roundy, vice president of marketing at Linux NetworX.

There's a major difference compared with Livermore system, though: The Los Alamos machine has no hard drives. Instead, each computer fires up using software pulled over the network with the assistance of software called LinuxBIOS developed by LANL programmer Ron Minnich and others. LinuxBIOS also dramatically speeds the startup process to about two seconds, said Jason Lowry, Linux NetworX's product manager for cluster management tools.

Shunning hard drives cuts cost and power consumption, but more importantly, it improves reliability, Roundy said.

"If you think about what things are going to fail in a system, it's the hard disk or fan or power supply or something with moving parts," Roundy said.

Linux NetworX could benefit greatly from convincing the Los Alamos and Livermore labs that Linux clusters are worthwhile. The labs are funded by the Energy Department's Advanced Simulation and Computing program, which has spent hundreds of millions of dollars to advance supercomputing using machines made of comparatively inexpensive components.

The DOE program has underwritten many of the world's fastest computers, according to university researchers who monitor raw calculation speed at the Top500 organization. The program has underwritten Nos. 2, 6, 7, 9, 11, and 15 on the most recent ranking.

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