5 ms·

That approach works if you know exactly what applications your code will ever be used for. If you are writing a library or a compiler or anything that will pote

That approach works if you know exactly what applications your code will ever be used for. If you are writing a library or a compiler or anything that will potentially be reused by unknown 3rd parties, then you can't be sure just how critically it will be put to use. There is no certification to distinguish software that lives can depend on. That doesn't mean it's your fault if someone uses your free XML parser in an amusement park ride and your bug makes it fly off the rails. But I still wouldn't feel very good about it and would like to do everything I can to avoid it. Also, when it comes time for you to write life or death code, it would be good if you already knew how to meet the required quality standard.

davidw 16y ago
You seem to have written this after my edit, which addresses that point. I'd feel bad too, but I'd feel bad if I had to hire a team of coders to review every line of my open source projects and document any change: > "At the on-board shuttle group, about one-third of the process of writing software happens before anyone writes a line of code. NASA and the Lockheed Martin group agree in the most minute detail about everything the new code is supposed to do -- and they commit that understanding to paper, with the kind of specificity and precision usually found in blueprints. Nothing in the specs is changed without agreement and understanding from both sides. And no coder changes a single line of code without specs carefully outlining the change. Take the upgrade of the software to permit the shuttle to navigate with Global Positioning Satellites, a change that involves just 1.5% of the program, or 6,366 lines of code. The specs for that one change run 2,500 pages, a volume thicker than a phone book. The specs for the current program fill 30 volumes and run 40,000 pages." From: http://www.fastcompany.com/node/28121/print http://www.fastcompany.com/node/28121/print If there's no certification for ready-made life critical components, then that means the burden of reviewing, checking and verifying everything in the system is on whoever wants to use it in a life-critical environment.
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.
  - 16y ago
kiujygtyujik 16y ago
This did meet the requirements for what it would be used for. Intended to be based in Germany in the 60s facing the Russians it wouldn't be powered up for 600 hours, because in 60 hours you would have been overrun.
- ImperatorLunae 16y ago
  There's an old Tom Lehrer song, "So Long, Mom," about just that: http://www.youtube.com/watch?v=pklr0UD9eSo http://www.youtube.com/watch?v=pklr0UD9eSo
  - kiujygtyujik 16y ago
    The British vulcan bombers of the same era had the range to reach Moscow - but not the range to return to the UK.
    - gaius 16y ago
      I don't think that's true - Vulcans hold the record for the longest bombing mission even today (during the Falklands war). The secret is air-to-air refuelling...
      - fgf 16y ago
        might be hard to do that somewhere over poland if ww3 just started
        gaius 16y ago
        USAF wargames discovered against F22s the most effective strategy to use would be tanker denial. Tho' with 4th generation fighters you would still need to outnumber them 6:1 (!)
        kiujygtyujik 16y ago
        The astronomer Freeman Dyson was part of the operational analysis team in WWII that worked out it made most sense to only search for and attack refuelling and resupply U-Boats (milkcows) The Vulcan flight gear famously included hiking boots so the crews could walk to Turkey after completing their mission
stretchwithme 16y ago
ultimately, it is the responsibility of the integrator to test their systems, including the software. And they have the source code for everything. Its like Apple X 100.

davidw 16y ago

You seem to have written this after my edit, which addresses that point. I'd feel bad too, but I'd feel bad if I had to hire a team of coders to review every line of my open source projects and document any change: > "At the on-board shuttle group, about one-third of the process of writing software happens before anyone writes a line of code. NASA and the Lockheed Martin group agree in the most minute detail about everything the new code is supposed to do -- and they commit that understanding to paper, with the kind of specificity and precision usually found in blueprints. Nothing in the specs is changed without agreement and understanding from both sides. And no coder changes a single line of code without specs carefully outlining the change. Take the upgrade of the software to permit the shuttle to navigate with Global Positioning Satellites, a change that involves just 1.5% of the program, or 6,366 lines of code. The specs for that one change run 2,500 pages, a volume thicker than a phone book. The specs for the current program fill 30 volumes and run 40,000 pages." From: http://www.fastcompany.com/node/28121/print http://www.fastcompany.com/node/28121/print If there's no certification for ready-made life critical components, then that means the burden of reviewing, checking and verifying everything in the system is on whoever wants to use it in a life-critical environment.

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.
- 16y ago

kiujygtyujik 16y ago

This did meet the requirements for what it would be used for. Intended to be based in Germany in the 60s facing the Russians it wouldn't be powered up for 600 hours, because in 60 hours you would have been overrun.

ImperatorLunae 16y ago
There's an old Tom Lehrer song, "So Long, Mom," about just that: http://www.youtube.com/watch?v=pklr0UD9eSo http://www.youtube.com/watch?v=pklr0UD9eSo
- kiujygtyujik 16y ago
  The British vulcan bombers of the same era had the range to reach Moscow - but not the range to return to the UK.
  - gaius 16y ago
    I don't think that's true - Vulcans hold the record for the longest bombing mission even today (during the Falklands war). The secret is air-to-air refuelling...
    - fgf 16y ago
      might be hard to do that somewhere over poland if ww3 just started
      - gaius 16y ago
        USAF wargames discovered against F22s the most effective strategy to use would be tanker denial. Tho' with 4th generation fighters you would still need to outnumber them 6:1 (!)
        kiujygtyujik 16y ago
        The astronomer Freeman Dyson was part of the operational analysis team in WWII that worked out it made most sense to only search for and attack refuelling and resupply U-Boats (milkcows) The Vulcan flight gear famously included hiking boots so the crews could walk to Turkey after completing their mission

stretchwithme 16y ago

ultimately, it is the responsibility of the integrator to test their systems, including the software. And they have the source code for everything. Its like Apple X 100.