# Software Question: What if a bit flips in critical applications? **URL:** \ **Category:** Factual Questions\ **Created:** [June 27, 2009, 12:20pm UTC](https://boards.straightdope.com/t/software-question-what-if-a-bit-flips-in-critical-applications/501163 "2009-06-27T12:20:26Z")\ **Posts on this page:** 4\ **Page:** 2
**Author:** ![alterego](https://avatars.discourse-cdn.com/v4/letter/a/6bbea6/32.png) [@alterego](https://boards.straightdope.com/u/alterego)\ **Post date:** [June 29, 2009, 7:11am UTC](https://boards.straightdope.com/t/software-question-what-if-a-bit-flips-in-critical-applications/501163/21 "2009-06-29T07:11:38Z")
IBM published a study that demonstrates a computer gets hit with a cosmic ray once per month. ---
**Author:** ![griffin1977](https://avatars.discourse-cdn.com/v4/letter/g/977dab/32.png) [@griffin1977](https://boards.straightdope.com/u/griffin1977)\ **Post date:** [June 29, 2009, 7:52am UTC](https://boards.straightdope.com/t/software-question-what-if-a-bit-flips-in-critical-applications/501163/22 "2009-06-29T07:52:22Z")
A quick google found [this](http://www.lanl.gov/news/releases/archive/04-044.shtml)article. Looks like the LANL are actively looking at this kind of thing. The focus seems to be planes and such rather than safety critical systems at see level: > [@](#): > > In the case of the latest, totally computer-controlled aircraft, these tiny cosmic gremlins could cause trouble, especially because the problem gets worse as atmospheric shielding dwindles at higher altitudes. At sea level, the shielding provided by the air is equivalent to more than ten feet of concrete shielding. The neutron flux at LANSCE, 7,000 feet above sea level is approximately three times greater than at sea level; and at 40,000 feet, the cosmic-ray neutron flux is several hundred times greater than the neutron flux seen on the earth’s surface. [Here](http://lansce.lanl.gov/NS/instruments/ICEhouse/index.html)is the web page for that dept in LANL (Edit - you can even [apply](https://wnr-proposals.lanl.gov/index.shtml)for some time in the beam to give your electronic corcuit special neutron super powers 🙂 ). ---
**Author:** ![Voyager](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voyager/32/133_2.png) [@Voyager](https://boards.straightdope.com/u/Voyager)\ **Post date:** [June 29, 2009, 5:00pm UTC](https://boards.straightdope.com/t/software-question-what-if-a-bit-flips-in-critical-applications/501163/23 "2009-06-29T17:00:09Z")
> [@griffin1977](#): > > [Here](http://lansce.lanl.gov/NS/instruments/ICEhouse/index.html)is the web page for that dept in LANL (Edit - you can even [apply](https://wnr-proposals.lanl.gov/index.shtml)for some time in the beam to give your electronic corcuit special neutron super powers 🙂 ). Don’t laugh - we do it all the time to confirm the reliability calculations and to see if there is something we’re missing. As for the IBM result - I have some experience that says they designed some of their memories for this case - unfortunately the real number is a lot higher. ---
**Author:** ![alterego](https://avatars.discourse-cdn.com/v4/letter/a/6bbea6/32.png) [@alterego](https://boards.straightdope.com/u/alterego)\ **Post date:** [June 29, 2009, 11:38pm UTC](https://boards.straightdope.com/t/software-question-what-if-a-bit-flips-in-critical-applications/501163/24 "2009-06-29T23:38:20Z")
> [@Voyager](#): > > Don’t laugh - we do it all the time to confirm the reliability calculations and to see if there is something we’re missing. > > As for the IBM result - I have some experience that says they designed some of their memories for this case - unfortunately the real number is a lot higher. They put the computer in a cave that is deep underground. [Previous page](https://boards.straightdope.com/t/software-question-what-if-a-bit-flips-in-critical-applications/501163.md?page=1)