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The Perennial Student of Chips

September 30, 1996|KATHLEEN WIEGNER

Semiconductors serve a multitude of purposes in everyday life. But Stanford University and chip maker LSI Logic Corp. of Milpitas, Calif., are designing and building a chip whose only purpose in life is to be tested.

As computer chips grow larger and more complex and are driven at ever higher speeds, it is becoming much harder to identify those that do not deserve a passing grade. Just 10 years ago, a single chip contained thousands of transistors operating at a few million cycles per second. Today a chip may carry tens of millions of transistors and operate at hundreds of millions of cycles per second. Ten years from now, these numbers may well be in the billions.

In the past, chip manufacturers solved the testing problem by building bigger and faster electronic testers. But as chips grow more complex, this strategy has gotten too expensive.

That's why Stanford's Center for Reliable Computing and LSI Logic launched a three-year effort to improve how chips are tested. The study will evaluate all performance aspects of state-of-the-art chips, including logic, memory and other mixed-signal circuits. It will also explore several advanced testing procedures, such as design-for-test and built-in self-test techniques.

What's Cooking? Using the parts from a 1,000-watt kitchen microwave oven, Michael M. Micci, an associate professor of aerospace engineering at Penn State University, is cooking up what he believes is a cheaper, safer thruster for positioning and maneuvering satellites in space. Counting their fuel, current chemical positioning and maneuvering systems for communications satellites make up a very large fraction of total launch weight. The microwave-thruster, of which Micci has developed a prototype, has the potential to reduce the amount of propellant needed by up to 50%. The difference could be used to install more payload on the satellite or to save on launch costs.

The idea for a microwave thruster has been around for more than a decade, but Micci says his prototype is the only one undergoing active ground testing. The thruster concept is based on the principle that microwaves can be used to create and maintain a free-floating plasma, or electrically charged gas, within a cavity. When a cold gas is passed through or around the plasma in the cavity, it becomes superheated, creating thrust when allowed to flow out through a nozzle. Because the plasma creates temperatures higher than those possible by chemical combustion, it creates more thrust with less fuel. Micci and his commercial partner, Research Support Instruments Inc. of Lanham, Md., have applied for patents on the prototype device.

Blowing Bit by Bit: Nothing, it seems, is untouched by the Internet, including Old Faithful. No trip to Yellowstone National Park would be complete without watching the famous geyser. But thanks to San Francisco-based Worlds Inc. and the Interior Department, Old Faithful is going online. Worlds, which creates 3-D virtual environments on the Internet, has created a cyber-geyser as one of its interconnected Web of Worlds. Visitors to virtual Old Faithful, however, will be able to do a lot of things that visitors to the real geyser can't, including visiting the magma chamber below it and getting blown up through the opening when it erupts. In the future, Worlds plans to let you track real wolves in the park. A satellite uplink would take positioning information from tagged wolves and deliver it to the computer. Worlds sees virtual Old Faithful as a prototype for virtual versions of other national parks and the first in a series of environments such as an Amazon rain forest for desk-chair travelers.

Browser for the Blind: For people who are visually impaired, cyberspace has pretty much been closed space. There are screen-access programs that work with browsers from Netscape Communications and Microsoft to convert text into speech. But Productivity Works in Trenton, N.J., has gone one step beyond by integrating the two into a talking browser that reads the text on Web pages aloud.

The WebSpeak browser functions like Netscape's Navigator. Following voice prompts, a user types in the URL, or Internet address, being sought. When the site appears on the screen, WebSpeak not only reads the text, but tells a user where graphics appear and what the page looks like. Text that appears in columns is reformatted so it can be read straight across the screen. The browser supports browsing by page, paragraph, hypertext link, heading, word (including the ability to spell any word) or simply reading an entire page. It also enlarges the print if needed.

Productivity Works believes WebSpeak will also be useful in help children with dyslexia and learning disorders, in a rehabilitation regimen for patients with brain injuries, and in providing support for language learning.

Freelance writer Kathleen Wiegner can be reached at

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