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<br>On a sidebar you see the same concept in processors for use in satellites or <br>other rad-hard application, anywhere where alpha particles are likely to<br>flip a register in the hardware.<br>The common design technique is Triple-Mode Redundancy (TMR) i.e.<br>replicating the circuit three times, rule-of-three-voting etc.<br>(Read the legal disclaimers on what applications Xilinx FPGA chips<br>(which use CMOS memory for configuration) cannot be certified for if you<br>want a good laugh... that's why those applications use antifuse instead)<br><br>As for memory in enterprise computing, you always use ECC protection on it.<br><br>Another amusing story from hardware certification was that in occasional cases<br>the actual semiconductor package of a chip (such as packages containing lead)<br>contained trace heavy metals which themselves produced a non-negligible level<br>of alpha-particle radiation (possibly higher than background radiation, due to <br>proximity), and that was hard to certify. (But sometimes you're stuck with<br>using lead for its superior thermal conductivity)<br><br>Stephen<br><br>> Date: Mon, 16 Mar 2009 23:59:14 -0700<br>> From: jjinux@gmail.com<br>> To: charles.merriam@gmail.com<br>> CC: Baypiggies@python.org<br>> Subject: Re: [Baypiggies] Silent data corruption paper...<br>> <br>> On Mon, Mar 16, 2009 at 11:09 PM, Charles Merriam<br>> <charles.merriam@gmail.com> wrote:<br>> > I owed this to someone at the last meeting:<br>> > http://fuji.web.cern.ch/fuji/talk/2007/kelemen-2007-C5-Silent_Corruptions.pdf<br>> ><br>> > Highlights: Desktop disks get a random silent corruption 10x more<br>> > than enterprise hard drives. Everyone gets them occasionally. Figure<br>> > a bit gets switched every couple of months in a data center, even with<br>> > all the backups, checksums, etc.<br>> <br>> I remember hearing that Google operated at such a large scale that<br>> these sorts of things tended to catch up with them. Their approach<br>> was to use more redundancy.<br>> <br>> I'm regurgitating things I've heard.<br>> <br>> -jj<br><br /><hr />Windows Live™: Keep your life in sync. <a href='http://windowslive.com/explore?ocid=TXT_TAGLM_WL_allup_1b_explore_032009' target='_new'>Check it out.</a></body>
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