DEVELOPING AND DESIGNING NEW CHEMICALS AND MATERIALS - Chemistry: Notable Research and Discoveries - page 23

This computer, Blue Gene/L at the Lawrence Livermore National
Laboratory in California, is one of the world's fastest computers
and can perform simulations of many physical processes. (Lawrence
Livermore National Laboratory)
diminished—more data needs to be stored in smaller areas. The prob-
lem is that the bits are becoming so small that they contain only a few
particles. As described in the sidebar on pages 20-21, while the behav-
ior of large numbers of particles is predictable, individual particles are
not. Fluctuations due to temperature could also cause magnetic fields to
change and flip between configurations. As a result, computer storage
may become unreliable if it is confined in too small a space.
Stocks, Wang, and their colleagues used an extremely powerful com-
puter made by Cray, Inc., called an XT3, to simulate the behavior of a
few thousand atoms in the material. This computer, located at the Pitts-
burgh Supercomputer Center, has 2,048 computer processors to speed up
operations; it so fast it is called a supercomputer. Even so, a simulation
of 14,400 atoms, including all their important interactions, required 50
hours of computer time. (Since the computer was shared with other us-
ers, not all the processors were devoted to this simulation.)
Iron-platinum and similar materials require a lot of energy to alter
their magnetic properties, making these substances stable and a good