|Multicore reduced to sand!|
|Written by Mike James|
|Thursday, 01 April 2010|
Multi-core processors are targetted by a new virus - called Renderman - that can literally turn a silicon chip back into the sand that it came from - today's breaking news.
Multi-core processors are the way of the future but they also bring new dangers. In particular they are vulnerable to a type of threat that breaches the barrier between software and hardware.
Using sophisticated signal processing algorithms the new virus - called Renderman - can literally turn a silicon chip back into the sand that it came from.
The original idea was good but not effective enough to be really practical. Each time a machine instruction is obeyed a particular part of the processor is active and the rest is quiescent. This means that the power dissipation across the die varies according to the instruction being executed. In normal operation the mix of instructions can be approximated by a random distribution and given time for the heat to dissipate and spread across the die the result is an averaged out heating effect. The chip gets hot but it gets hot evenly.
However, once the effect was noticed it was only a matter of time before creative programmers succeeded in writing a program that had an asymmetric mix of instructions that heated one part of the die while keeping another cool. Running the program so as to create a flip-flop effect, sections of the chip could be heated and cooled in a cyclic fashion. The heating causes expansion and contraction in the same cyclic manner and the chip starts to vibrate. Early tests proved that the concept was workable and soon processors were producing single audible tones which could sometimes be heard with the cooling fan still on. However the big problem was that the tiny area of silicon involved in any particular instructions execution was too small to make a loud enough noise. The most that could be achieved was a rendition of "happy birthday" which could be heard in its entirety as long as the cooling fan was switched off. And so the technique lay dormant only to be revived when something really new changed the equations involved.
The introduction of multi-core processors suddenly revitalised the research. Now fairly large areas of the die could be heated and cooled by creating multi-threaded versions of the original algorithm. By solving the complex differential equations an inverse solution could be found which enabled the implementation of code that could make the die vibrate like a drum head. Not only was the sound now loud enough to hear over the cooling fan but it was loud enough to have physical effects. The system could, with the addition of a feedback loop, be forced into catastrophic resonance. As the amplitude of oscillation increases the very crystal structure of the silicon chip starts to fail as dislocations propagate and accumulate into large cracks. This builds up to the point where the chip fails with a loud popping noise and and is reduced back to its original form, i.e. pure sand.
With the addition of some autogenic transmutation code to keep the virus hidden while it attempt to deliver its payload, the Renderman virus was born. So far an example has not be found in the wild but we need to be on the lookout for the first instances. The first signs are a high pitched buzzing sound coming from the approximate location of the processor which rapidly increases in volume as the chip prepares itself to be rendered back to powdered SiO2.
Of course there are many users who feel that reducing the processor chip back to a few grains of sand is perhaps a fitting end and an ecologically sound approach to obsolescence.
Being programmers we know better – don’t we.
And, oh yes, I forgot to mention, the activation date of the Renderman virus is 4/1/2010.
Yes - this IS an April fools hoax.
It is an updated version of the Sandman virus joke which was first published as an editorial in VSJ magazine in 1998.
After reading it your only real question should be -could it work?
|Last Updated ( Thursday, 01 April 2010 )|