The Last Stop For Space Station-Bound Software 39
Normally I avoid slide show type articles, but this one is actually pretty interesting. It starts "This NASA lab contains a recreation of the computer systems found onboard the International Space Station. It is the place where the final bug testing takes place before software is uploaded to the station and where software engineers recreate bugs that occur onboard the station in an attempt to help fix them."
Re:Testing? (Score:4, Interesting)
They have to make sure the "aquarium" screensaver works anywhere.
Those fish have trouble in zero gravity.
Re:I wonder... (Score:3, Interesting)
The cool story here is that the idea that you could have a triple-redundant system fail seemed so far off that it was almost thought impossible.
Heh, well it would be, if the estimated probability of failure for each was truly an independent random variable. The excrement usually hits the fan when it isn't. Like, say, a hard drive with an unknown defect where a certain access pattern can make it fail. 3 machines doing the same work means they could all fail for the same reason at about the same time.
Or an old example that was basically just doing "redundancy" wrong, the telco that laid two fiber optic cables -- you know, cus the CTO read that redundancy was important! -- directly side by side. So when the inevitable backhoe came along and accidentally cut one, it cut both.
All is fine now. I believe they have replaced the hard drives with space hardened solid state drives...
Huh... Do you have any idea what the failure mode was? If it was a solar storm or other such event, then it would make perfect sense that all 3 systems conked out at the same time in defiance of all probability.
Anyway, that is pretty cool. And it shows the kind of folks who work at NASA that they decided that triple redundancy just wasn't enough and they needed a last-ditch recovery mechanism.