5 ms·

There is no certification to distinguish software that lives can depend on. Actually, there is. Google up "safety-critical software". And maybe "trusted soft

by Dove 16y ago

There is no certification to distinguish software that lives can depend on. Actually, there is. Google up "safety-critical software". And maybe "trusted software". I work in military avionics; every dang line of code in the product, including any libraries we use, is vetted to death. If I were to try to just download a library off the internet and include it in the flight control software, I (A) wouldn't get away with it (B) would probably lose my job and (C) would confuse the hell out of my coworkers who all know I know better than that. So don't worry someone will include your hastily-developed XML parser in safety-critical software without your knowledge. They won't unless you're willing to prove you've certified it to the level they require. And I promise you, that's not an exercise you'll forget having gone through. ;)

ssp 16y ago
But then, how on earth did they manage to get this software certified if it did something as DailyWTF-worthy as using floating point for a clock?
- Dove 16y ago
  Yeah. You should see some of the other stuff that makes it into production code. I said there was a process. I didn't say the result was good software. ;)
- fshaun 16y ago
  Collection of bits are put to truly horrible uses in the name of efficiency.
- tetha 16y ago
  Well I have to give them that this is kind of a curious bug. I mean, you have to wait over 4 days until it triggers. Probably, this just worked whenever it was booted and tested, and booted and certified, because probably the certification did not involve ignoring the thing for four full days.
  - phaedrus 16y ago
    According to a book I read about game testing it's common for commercial games to be run through a test of simply leaving the game on for hours or days to see if there are bugs that only show up in this way.
- gnaffle 16y ago
  According to http://www.cs.unc.edu/~dm/UNC/COMP205/LECTURES/ERROR/lec23/node4.html http://www.cs.unc.edu/~dm/UNC/COMP205/LECTURES/ERROR/lec23/n..., the system stored the time in integers, but it was converted to floating point when doing the conversions. This conversion contained a small error that accumulated over time. Keep in mind that things that seem very WTF to you, might seem more plausible when given more details about the subject.
- regularfry 16y ago
  In part because the user manual included instructions to regularly reboot before precision became a problem. The users did not, because they didn't want to risk being in the middle of a reboot when a target went overhead.
extension 16y ago
My mistake, but this kind of methodology seems to be specific to a few industries like aviation and space, while being conspicuously absent from e.g. medicine. Ideally, the software industry would have its own life-critical standard that was applied across all domains, not that I'm suggesting such a standard is necessarily feasible right now. Until we have such a universal standard, it is entirely possible for a bug in your free library to indirectly kill someone, in the course of everyday best practices.
- slavak 16y ago
  I have an incredibly hard time believing the medical industry does not have stringent standards in place for safety-critical software. Do you have anything to demonstrate this, and what country are we talking about here? (To remind me not to ever see a doctor there... :) )
  - extension 16y ago
    http://www.nytimes.com/2010/01/24/health/24radiation.html http://www.nytimes.com/2010/01/24/health/24radiation.html
- farmerbuzz 16y ago
  In the US, medical devices are regulated by the FDA. When it comes to using 3rd party software, the company manufacturing the device has the responsibility to ensure any 3rd party components function correctly. Its unrealistic to impose regulations on every piece of software that is written "just in case". It is far more practical to put the responsibility on the company doing the integration and selling the device. Here is the guidance from the FDA on off-the-shelf software: http://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/ucm073778.htm http://www.fda.gov/MedicalDevices/DeviceRegulationandGuidanc...

by Dove 16y ago

ssp 16y ago

But then, how on earth did they manage to get this software certified if it did something as DailyWTF-worthy as using floating point for a clock?

Dove 16y ago
Yeah. You should see some of the other stuff that makes it into production code. I said there was a process. I didn't say the result was good software. ;)
fshaun 16y ago
Collection of bits are put to truly horrible uses in the name of efficiency.
tetha 16y ago
Well I have to give them that this is kind of a curious bug. I mean, you have to wait over 4 days until it triggers. Probably, this just worked whenever it was booted and tested, and booted and certified, because probably the certification did not involve ignoring the thing for four full days.
- phaedrus 16y ago
  According to a book I read about game testing it's common for commercial games to be run through a test of simply leaving the game on for hours or days to see if there are bugs that only show up in this way.
gnaffle 16y ago
According to http://www.cs.unc.edu/~dm/UNC/COMP205/LECTURES/ERROR/lec23/node4.html http://www.cs.unc.edu/~dm/UNC/COMP205/LECTURES/ERROR/lec23/n..., the system stored the time in integers, but it was converted to floating point when doing the conversions. This conversion contained a small error that accumulated over time. Keep in mind that things that seem very WTF to you, might seem more plausible when given more details about the subject.
regularfry 16y ago
In part because the user manual included instructions to regularly reboot before precision became a problem. The users did not, because they didn't want to risk being in the middle of a reboot when a target went overhead.

extension 16y ago

My mistake, but this kind of methodology seems to be specific to a few industries like aviation and space, while being conspicuously absent from e.g. medicine. Ideally, the software industry would have its own life-critical standard that was applied across all domains, not that I'm suggesting such a standard is necessarily feasible right now. Until we have such a universal standard, it is entirely possible for a bug in your free library to indirectly kill someone, in the course of everyday best practices.

slavak 16y ago
I have an incredibly hard time believing the medical industry does not have stringent standards in place for safety-critical software. Do you have anything to demonstrate this, and what country are we talking about here? (To remind me not to ever see a doctor there... :) )
- extension 16y ago
  http://www.nytimes.com/2010/01/24/health/24radiation.html http://www.nytimes.com/2010/01/24/health/24radiation.html
farmerbuzz 16y ago
In the US, medical devices are regulated by the FDA. When it comes to using 3rd party software, the company manufacturing the device has the responsibility to ensure any 3rd party components function correctly. Its unrealistic to impose regulations on every piece of software that is written "just in case". It is far more practical to put the responsibility on the company doing the integration and selling the device. Here is the guidance from the FDA on off-the-shelf software: http://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/ucm073778.htm http://www.fda.gov/MedicalDevices/DeviceRegulationandGuidanc...