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Intel Patents On-Chip Cosmic Ray Detectors
holy_calamity writes "Intel has been awarded a patent for building cosmic ray detectors into chips, to guard against soft errors where a high energy particle from space changes a value in a circuit. It's a problem that largely only affects RAM. As component sizes shrink futher, "this problem is projected to become a major limiter of computer reliability in the next decade", says the patent. Intel's solution is to build in a detector that responds to cosmic errors by repeating the latest operation, reloading previous instructions, or rolling back to a previous state. You can also read the full patent."
But you can't really verify it because those events are so rare. It seems to me that Intel's innovation is to use some sort of detector, instead of using two or more chips and a comparator. It's probably way cheaper, but it won't work if the majority of unexplainable events are not, in fact, caused by cosmic rays but by some other effect (perhaps something temperature-related).
How did they manage to build a detector that can work out whether the cosmic rays collided with the actual bits (no pun intended) that hold the data? According to the oracle, cosmic rays collide with nuclei in an essential random way, so there's no way a detector could just see a ray passing through and know whether it was on a collision course. Perhaps they are detecting the pions and other subatomic particles that result from a collision actually occurring? If they've found a way to do that then it sounds fairly ingenious to me and a well-deserved patent.
apterous.org
It's just as likely registers could be corrupted, or the "rollback" state. Wouldn't be easier to have, I dunno, maybe error correction/detection involved, instead of some arbitrary cosmic ray detector?
Sometimes the more "esoteric" designers attempt to get simply leads to more potential for disaster.
Cosmic ray detection would be far better for random number generation, than anything else.
It won't take long for someone to figure out how to detect the gamma errors and create what amounts to a geiger counters on laptop computers. If this bill passes http://www.villagevoice.com/news/0803,thompson,78873,2.html will everyone be required to get a permit for their laptop computers? ;-)
Currently, chips (both computational and memory) are protected against soft errors using multiple methods. There are rad hardening methods (both hardware and software) and most of the latest research involves using error correcting codes. Simply duplicating the output and comparing can only detect errors in one bit. The more the times you duplicate, the more you can detect (it progresses as n-1), and the max length of error that can be corrected is half that. However, this takes a lot of space (duplication that is), so generally other codes such as Hamming or BCH codes are used.
The main problem using codes and everything is that cosmic ray errors cause whats called single event upsets and most codes can not detect 100% of errors where the hamming weight of the error (sum of number of ones in the error vector) is larger than the designed specification of the error. The problem comes when the SEU manifests itself as a multi-bit fault and the error vector cannot be detected by the code. SEU's are the most common type of errors in space application : See http://www.eas.asu.edu/~holbert/eee460/see.html
The contribution of the cosmic error detector is that if you know you have a cosmic ray at some point in time, you can flush and redo your computation (for computation channels eg microprocessors etc) or flush that line in memory (for memory channels) in case of SEU's and that is a pretty big deal.
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This subject reminds me of a paper I saw some time ago, on a way to use the cosmic rays to your advantage and breaking out of the JVM. Here's the link: http://www.cs.princeton.edu/sip/pub/memerr.pdf
Its widely acknowledged that Intel created EMF burst proof chips for the government. The technology inside of them was never publicly discussed. I think it might be similar to cosmic ray correction. They might just be patenting a sub set of it now before the shrinking die sizes cause someone else to patent technology they've been using for years.
Well.. maybe. Or Maybe not. But Definitely not sort of.
Microsoft's XP crash analysis early in this decade concluded that PCs always left on tended to crash unexpectedly. Dump analysis showed strange values in key OS variables, and cosmic rays (or other bit-blasting particles) were among the likely sources. The conclusion was so clear that Microsoft floated the idea (see URL above) that Vista-generation PCs should use Error-Correcting Code (ECC) memory to detect and fix multi-bit errors -- in consumer PCs. [Note that servers and business workstations have used ECC memory for decades].
Having seen corrupted data in my own copy of Microsoft Money and other applications that I have left open for weeks, I am prepared to accept cosmic rays as well as Microsoft bugs as potential sources. Finally, why would Intel invest R&D capital in a cosmic ray detector if it had no likely or practical use for Intel's consumer and business customers?