Supercomputers are cool.

After two and a half years at the top of a list of the world's fastest supercomputers, NEC's Earth Simulator has finally been dethroned: IBM's Blue Gene/L officially is the new king of the hill.

The Blue Gene/L succession, while expected, reflects IBM's sustained push in recent years to expand its expertise from business computers into high-performance technical computing. On the newest incarnation of the Top500 list, updated twice a year, IBM has 216 systems, which account for 49.4 percent of list members' collective performance.

The ascendance also highlights the rise of Linux, the open-source operating system that Blue Gene/L runs and that IBM helped to champion. The new No. 2 system, Silicon Graphics' Columbia, also uses Linux.

Blue Gene/L performed 70.7 trillion calculations per second, or teraflops, nearly twice the 35.9 teraflops of Earth Simulator. And as expected, Columbia was clocked at 51.9 teraflops. IBM's new MareNostrum, at 20.5 teraflops, arrived in fourth place.