For years, the rallying cry of the cognoscenti in the field of configurable computing has been "obtain the performance of hardware with the flexibility of software." The goal is to create a kind of "virtual," easily configurable hardware that can be allocated to different computing processes in real time.
Of course, scientists are not quite there yet. But with a little funding help from their friends at the Pentagon's Defense Advanced Research Projects Administration, they're starting to make some interesting progress.
Peter Athanas, an associate professor of electrical engineering at Virginia Polytechnic and State University, and his colleagues are now planning the second stages of a DARPA project that performs configurable computing using something called the "wormhole runtime reconfiguration." The software executes programs directly on a program's hardware, eliminating the bottleneck of a central microprocessor.
In wormhole computing, the "computational hardware is essentially swapped in and out of the platform as needed, much like paging in virtual memory systems on a conventional computer," says Athanas.
Athanas' description sounds like something straight out of a William Gibson novel: Streams of data tunnel through a computer, creating their own computational pathways. "It is much like a normal network IP header," Athanas said. "But the header contains information about how to steer the data through the computing platform. We present the stream to the perimeter of the platform and it tunnels through, like a worm."
Computer scientists see configurable computing providing two significant benefits: Results are produced as fast as the data is presented to the platform; and there is a significant power savings, since the computer doesn't have to perform instruction fetches, as it would with a central processor.
The system's heart, a custom-designed circuit codenamed Colt by Virginia Tech, has achieved a reconfiguration bandwidth of 4.8 billion bits of configuration information per second through the I/O pins. By contrast, the configurable computing circuits used today, called Field Programmable Gate Arrays, are significantly slower.
Athanas' first experiments were recently conducted with a mock-up CDMA cellular-phone application. The next stage of the project aims to tackle even bigger computational platforms, though the technology won't have commercial applications for five to ten years.
Experts view the advances as developments fitting in the world somewhere between conventional silicon microprocessors and Application-Specific Integrated Circuits. "His area is probably more advanced than most in terms of architecture," says Tim Garverick, design director of the soft logic technology group at National Semiconductor. "There are a number of open issues in the field. But his device is unique. It is an innovative concept."
But not everyone is so sure that wormhole computing is ready for prime time. "At this point, I am not convinced of it," said a government expert on configurable computing. "It is not something that I would say in 10 years is going to take over the world, but it is not a terrible idea. It needs to be looked at."
Athanas isn't rebuffed by those observations. "These are pretty far-out ideas. Companies are not daring enough to stick their necks out for ideas like this," concluded Athanas. "That's why we utilize government R&D money."
