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TWO researchers in Tennessee have shown again that one person鈥檚 trash is
another鈥檚 treasure. They have built a serviceable supercomputer by lashing
together a few dozen PCs containing the Intel 486 processor鈥攎achines that
today鈥檚 home computer users would turn their noses up at.
In 1996, computer scientist Forrest Hoffman and landscape ecologist Will
Hargrove of Oak Ridge National Laboratory鈥檚 environmental science department
asked the lab鈥檚 managers for funding to buy 16 state-of-the-art Pentium PCs to
build a 鈥淏eowulf鈥� supercomputer. A Beowulf consists of multiple PCs linked
together, and it attacks difficult calculations by dividing them up and
delegating these more manageable tasks to the smaller processors.
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Their request was denied. 鈥淲e got really frustrated,鈥� says Hoffman. 鈥淏ut we
weren鈥檛 going to give up.鈥� At the lab鈥檚 swap shop and by pestering colleagues,
the researchers scavenged the necessary networking equipment and a motley
collection of 486 PCs, which are now regarded as obsolete .
In a vacant lab, and during their spare time, they assembled the Stone Souper
computer. The name comes from the Stone Soup fable, in which a hungry soldier
claims he will make soup from a stone, then convinces people to donate enough
鈥渆xtra鈥� ingredients to make a real soup.
Eight months later, the Stone Souper has grown into a sprawling collection of
56 linked computers, and it can perform 1.5 billion floating-point operations
per second. That鈥檚 not enough for truly mammoth computational tasks, such as
modelling the flow of electromagnetic radiation in space. But it is more than
adequate for Hargrove鈥檚 project: showing how conditions for plant growth vary
across the US on maps with a resolution of one square kilometre.
In a month or two, when the researchers have expanded the Stone Souper to
their goal of 64 PCs, the machine will be able to incorporate 10 variables
influencing plant growth, including temperature, rainfall and soil
chemistry.
鈥淚n terms of raw power, it鈥檚 not the most macho thing,鈥� says John Cobb, a
computer specialist at Oak Ridge. But since its components were essentially
free, he adds that Stone Souper may set a new record for another popular
computer benchmark: the ratio of performance to price.
Hoffman also plans to soup up the Stone Souper, when people start throwing
away their current PCs. 鈥淲ithin the next year or so, we figure we鈥檒l start
getting Pentiums donated,鈥� he says.