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A long long long time ago (my first out of uni job) I used to do machine control systems (thankfully, not for aircraft) but there were often safety issues (so y

A long long long time ago (my first out of uni job) I used to do machine control systems (thankfully, not for aircraft) but there were often safety issues (so you didn't burn/crush/soak people with acid etc). We never used a turing complete programming language, as it was seen as too risky, was always something primitive like ladder logic (which seemed intuitively easy to reason over and forced simplicity and fail safe behaviour). I am not sure what has changed, but I wouldn't want to be doing stuff that different now with a general purpose programming language (be that Ada, Java or for reasons I would never understand, C).

prospero 18y ago
I dunno, you deal with the risk of standing on thin air no matter what you use, unless you've designed your device from the silicon up. There's not a strong argument to be made for using Java in an industrial setting, but I'm not clear that a finite-state machine that compiled down to JVM bytecodes would be inherently less safe than anything else. Ada doesn't guarantee the correctness of your program, and C certainly doesn't. This interview reads more like an inarticulate complaint about how things keep changing than a real argument against trends in education.
- cconstantine 18y ago
  Minor nit-pick. I work around (but not with) ada code, and a common pattern is that if you can get your ada code to compile; it's pretty likely that it's safe. If you're just saying Ada doesn't guarantee that the program does what you really need... no language can do that. C is the 2nd most unsafe language I've worked with, asm being the first.
  - prospero 18y ago
    If you're just saying Ada doesn't guarantee that the program does what you really need... no language can do that. That was basically my point. I agree Ada's pretty cool, but Dewar listed Ada and C (!) as the only two languages suitable for safety-critical systems. I mean, really. What does one say to that.
    - cconstantine 18y ago
      That was poorly worded. I meant to end that sentence by saying I agree with you :/ What does one say to someone who is using C because it's suitable for safety-critical systems? Please don't!

prospero 18y ago

I dunno, you deal with the risk of standing on thin air no matter what you use, unless you've designed your device from the silicon up. There's not a strong argument to be made for using Java in an industrial setting, but I'm not clear that a finite-state machine that compiled down to JVM bytecodes would be inherently less safe than anything else. Ada doesn't guarantee the correctness of your program, and C certainly doesn't. This interview reads more like an inarticulate complaint about how things keep changing than a real argument against trends in education.

cconstantine 18y ago
Minor nit-pick. I work around (but not with) ada code, and a common pattern is that if you can get your ada code to compile; it's pretty likely that it's safe. If you're just saying Ada doesn't guarantee that the program does what you really need... no language can do that. C is the 2nd most unsafe language I've worked with, asm being the first.
- prospero 18y ago
  If you're just saying Ada doesn't guarantee that the program does what you really need... no language can do that. That was basically my point. I agree Ada's pretty cool, but Dewar listed Ada and C (!) as the only two languages suitable for safety-critical systems. I mean, really. What does one say to that.
  - cconstantine 18y ago
    That was poorly worded. I meant to end that sentence by saying I agree with you :/ What does one say to someone who is using C because it's suitable for safety-critical systems? Please don't!