3 ms·

From years of debugging, I know I am unconsciously biased towards the view that a bug in my code or hardware is the result of a very low-probability event, and

From years of debugging, I know I am unconsciously biased towards the view that a bug in my code or hardware is the result of a very low-probability event, and strangely biased away from the view that a medium or high-probability series of events occurred for which I didn't perfectly plan. It always turns out to be the latter. Therefore, I will predict that this event is NOT a low probability double-bit error brought on by stray radiation that bypassed all safeguards. (Unless those NASA guys are superhuman designers, which I guess could be valid hypothesis.)

swah 14y ago
They aren't super human, but then have more eyes on each line of code that goes into space than most code..
XorNot 14y ago
Google feels that DRAM errors are about 8% per year from their studies. Cosmic ray interference is common enough to require deliberate software rejection modes when doing something Raman spectroscopy, so it's not like the probability of getting interference in memory chips is low. It's just normally, the probability you've made a glaring bug while coding is way higher (and punching the power button is much easier then dissecting kernel states to find out if it's really a cosmic ray).
- ars 14y ago
  Don't forget that there are far more cosmic rays on Mars: Thin atmosphere, plus no magnetic field.
andyjohnson0 14y ago
"Unless those NASA guys are superhuman designers, which I guess could be valid hypothesis." They Write the Right Stuff [1] - a little old now but worth a read. [1] http://www.fastcompany.com/28121/they-write-right-stuff http://www.fastcompany.com/28121/they-write-right-stuff
Sharlin 14y ago
The thing is that a cosmic particle event such as this is NOT an especially low-probability one when you're on Mars. Similar things have happened with Spirit and Opportunity as well, even earlier in their respective missions. The engineers expect things like this to happen. I don't think they have ever been wrong when attributing a glitch to a radiation event.

swah 14y ago

They aren't super human, but then have more eyes on each line of code that goes into space than most code..

XorNot 14y ago

Google feels that DRAM errors are about 8% per year from their studies. Cosmic ray interference is common enough to require deliberate software rejection modes when doing something Raman spectroscopy, so it's not like the probability of getting interference in memory chips is low. It's just normally, the probability you've made a glaring bug while coding is way higher (and punching the power button is much easier then dissecting kernel states to find out if it's really a cosmic ray).

ars 14y ago
Don't forget that there are far more cosmic rays on Mars: Thin atmosphere, plus no magnetic field.

andyjohnson0 14y ago

"Unless those NASA guys are superhuman designers, which I guess could be valid hypothesis." They Write the Right Stuff [1] - a little old now but worth a read. [1] http://www.fastcompany.com/28121/they-write-right-stuff http://www.fastcompany.com/28121/they-write-right-stuff

Sharlin 14y ago

The thing is that a cosmic particle event such as this is NOT an especially low-probability one when you're on Mars. Similar things have happened with Spirit and Opportunity as well, even earlier in their respective missions. The engineers expect things like this to happen. I don't think they have ever been wrong when attributing a glitch to a radiation event.