INFORMATION TECHNOLOGY

For Some Research, 'Piles of P.C.'s' Are
a Cheap Alternative to Supercomputers

In a frank tribute to the growing power and shrinking cost of personal computers, researchers at many universities are now linking P.C.'s together to create their own supercomputers -- at a fraction of what it would cost to buy systems of comparable power from companies like I.B.M. or Cray Research.

A system designed at the National Aeronautics and Space Administration's Goddard Space Flight Center, called Beowulf, allows technicians to build networks out of I.B.M.-compatible personal computers. Working together and in parallel, the P.C.'s can process complex research data as fast as -- or faster than -- larger computers that cost far more.

Traditional supercomputers are refrigerator-size cabinets that contain thousands of microprocessors. They work in much the same way as the linked P.C.'s in a Beowulf system, but the supercomputers are built with specialized components and software that can be operated only by expert technicians and programmers. The machines, which have their own cooling systems and require large amounts of electricity, cost between half a million and tens of millions of dollars.

Les Todd, Duke U., for The Chronicle Robert G. Brown, (above), a physics researcher at Duke University, has created a Beowulf system using 19 computers that are scattered throughout his department.

Beowulf systems use computers identical to those that sit on many people's desks -- machines that can be bought for less than $2,000 apiece. The wires and components used to connect the computers are the same as those in typical office networks. Beowulf systems are also scalable: They can be enlarged simply by adding more computers.

The software that makes a Beowulf network possible is Linux, an operating system developed largely by a volunteer group of computer experts who use and support it. Some versions of the operating system are sold commercially, but basic versions, and the programs needed for a Beowulf system, are available free on the Goddard center's Web site.

The California Institute of Technology has one of the largest Beowulf setups. Researchers use it for such tasks as simulating pollution patterns in southern California. Jan Lindheim, a computer analyst in the institute's computer-services department, says the system comprises 114 computers and is named Naegling, after Beowulf's sword. The total cost of the system, Mr. Lindheim estimates, was about $300,000. A single supercomputer with similar power, he says, could cost more than 10 times that.

More than 30 institutions have put together Beowulf systems, including Clemson, George Washington, Oregon State, and Texas Tech Universities, the University of Southern Mississippi, and the University of California at Irvine.

Rapid drops in the price of desktop computers, coupled with big jumps in their power, have posed a dilemma to research institutions accustomed to using larger, high-performance machines. Robert G. Brown, a physics researcher at Duke University, says that after you purchase such a machine and use it for a year, "you've spent $50,000, $60,000, or $100,000, and now it's worth $3,000 or $5,000." Meanwhile, desktop P.C.'s have grown more powerful, relative to supercomputers. Dr. Brown says, only half jokingly, that the computer on his desk "has more computing power than was available in the United States 15 years ago."

In most cases, universities' Beowulf systems are housed in racks or cabinets, making it easier for operators to connect the components -- and prompting many people to refer to the setups as "piles of P.C.'s." At Duke, however, Dr. Brown is stretching his system farther. Several of the 19 computers in his Beowulf system reside on desktops scattered throughout the physics department.

Professors, graduate students, and staff members use the machines for word processing or surfing the Web -- tasks that take only a fraction of a computer's power. Meanwhile, the $60,000 system is also chugging away at Dr. Brown's research into how changes in temperature affect magnetic fields. "We're double dipping," he says.

Dr. Brown has worked with parallel computer systems like Beowulf for several years, but in the past he has had to come up with his own ways of making the computers work together. The free Beowulf software makes it easy for an experienced Linux user to set up a system, he says. "We have graduate students," he says, "who have been able to handle almost all of it."

Background stories from The Chronicle on uses of parallel computing:

• "Encryption Enthusiasts on Campuses Help Crack Code of Stunning Complexity," 6/19/97
• "U.C. Berkeley Student Breaks Encryption Code," 2/6/97