Skip the navigation  Need a supercomputer? This guy builds them
himself  By Tim Greene February 2, 2009 12:00 PM ET   That was
in 1998, and since then he's built three more supercomputers,
all in pursuit of actually observing gravitational waves, which
theoretically emanate from black holes orbiting each other and
from exploding stars but have never been directly observed.  His
most recent supercomputer, a cluster of 1,680 machines with four
cores each, is in Hanover, Germany. Essentially, it's a
6,720-core processor that in the months after it was built was
ranked No. 58 in the world. "We filled our last row of racks
recently, and we're No. 79 on the current Top500 list," says
Allen, director of the Max Planck Institute.     The problem is
that big-name companies have a lot of overhead made up of layers
of management and engineering. "They do sell good products, and
you don't need to have any particular expertise to buy them," he
says. "It's always been my experience that if I do it myself, I
get more bang f