08 December 2005
Keeping things spinning
Multicore processors offer power saving benefits, but not without demanding more from operating systems. By Philip Ling.
It was identified a few years ago, by extrapolation, that transistor junction temperatures in integrated circuits could get as hot as the surface of the sun; or rather they wouldn’t, because they would melt first. The real problem was that the timeframe for that extrapolation was disturbingly close: something had to be done.
The advent of 130nm features and below put a lot of focus on power density; particularly at the transistor level. Techniques to reduce leakage current received special interest, because the rise in static leakage was outpacing the increase in the number of transistors integrated.
An example is dynamic body biasing, developed by Intel, which varies the threshold voltage dynamically. Threshold voltage is a double edged sword; a low threshold means a fast transistor, but a leaky one. By varying the threshold dynamically, the transistor can be fast when needed and slow – and so less leaky – when not. The application of transistors has also evolved. Replacing power vias with transistors, for instance, allows whole sections of a chip to be turned off when not in use, reducing leakage current to zero.
Author
Philip Ling
Supporting Information
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5659\keeping-things-spinning.pdf
Websites
http://www.qnx.com
http://www.windriver.com
Companies
QNX Software Systems Ltd
Wind River UK Ltd
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