April 1, 2005 4:00 AM PST
FAQ: Forty years of Moore's Law
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that electrons will drift over on their own. When that happens, transistors will lose their reliability, because it will be impossible to control the flow of electrons and hence the creation of 1s and 0s.
(The nanometer measurement refers to the average feature size on a chip. A nanometer is a billionth of a meter. Current chips are made on a 90-nanometer process, while experimental devices about 6 nanometers long have been produced.)
What happens then?
Hard to say. If alternatives to silicon transistors never materialize, Moore's Law stops. If alternatives emerge, progress could accelerate under similar principles.
What's the best alternative?
Who knows? Carbon
Silicon, though, won't go easy. Manufacturers and designers love it. Chances are, silicon will continue to be incorporated into these new devices in some fashion.
"I view (silicon) technology as a fundamental way for bringing out complex microstructures and materials," Moore said.
Who said what?
California Institute of Technology Professor Carver Mead was the one who dubbed it Moore's Law, a lofty title Moore said he was too embarrassed to utter himself for about 20 years. David House, a former Intel executive, extrapolated that the doubling of transistors doubles performance every 18 months. Actually, performance doubles more like every 20 months. Moore emphatically says he never said 18 months for anything.
The rule also doesn't apply to hard-drive densities or to the growth of other devices. "Moore's Law has come to be applied to anything that changes exponentially, and I am happy to take credit for it," Moore joked.
What does doubling do?
The impact can be summed up as follows: faster, smaller, cheaper. Under Moore's Law, chip designers essentially shrink the size of transistors--which are now measured in nanometers--and then fill up the resulting empty space on the chip with more transistors. More transistors let designers add features, such as 3D graphics, that used to exist on separate chips--thereby cutting costs.
The designers can also choose to dedicate more transistors to speeding up how the chip performs its usual functions. Despite the extra transistors, these enhanced chips cost about the same as the old ones, because they take up the same surface area of silicon.
As an added bonus, smaller transistors mean electrons don't have to travel as far, boosting performance. Though chip designs vary widely, manufacturers try to get some or all of these advantages.
How does that affect products?
Put into practice, Moore's Law spells out a way for companies to enhance their products at a rapid clip. Eighteen years ago, Michael Douglas, in the movie "Wall Street," spoke on a cell phone that was about the size and shape of a brick. Shrinkage and integration has lead to phones with television tuners, 7-megapixel cameras and MP3 players. Declining costs have also put them in the hands of billions of people.
More-powerful, cheaper chips have in turn allowed software makers to develop applications such as instant messaging, 3D games and Web
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