Also, it implies a couple of engineers could slip through arbitrary code to be executed under selective conditions. That's terrifying.
http://www.ldra.com/en/software-quality-test-tools/group/by-...
The industry also has specific coding standard for every language that is used in embedded systems like MISRA-C https://en.wikipedia.org/wiki/MISRA_C
Today every thing you do with your car from using breaks to deploying air-bags is done through the computer, there's no way in hell that the motor industry would be releasing poor code "intentionally" because it would cost them billions in liabilities.
"Barr checked the [Toyota] source code against MISRA’s 2004 edition and found 81,514 violations."
http://www.safetyresearch.net/blog/articles/toyota-unintende...
It is inaccurate to claim Michael Barr determined the cause of Toyota's unintended acceleration: he proposed a possible failure mode that was persuasive to a lay jury. His proposed failure mode didn't leave a DTC, so there's no way to actually know if his proposed failure mode actually happened in this case (or in any other).
NASA found 7000 and change Barr found over 81,000, I'm not sure whats the size of the code that was reviewed but that's allot, even if you count the fact that half of them might be silly like naming convention violations that still leaves quite an odd number for actual violations especially when considering that the code for an embedded system can't be that huge.
And the 10,000 global variables thing, well 10,000 sounds like a huge number but there wasn't any mention if they were a) necessary, b) implemented correctly, and c) out of how many variables in total? if the code they've tested has say 1 million variables then well.... And how they described global variables is also weird, they claimed that every software within the system can access them to me this sounds that your stereo or the rain sensor for the wipers can override data for the breaks, but that might be true only if everything is running within a single application.
If the breaks run as an independent application well then only every function within the break software (depending on the language and how global variables are implemented) could potentially access those variables.
To me pretty much that entire explanation seem to be constructed to sound worse than what it is, which is why I think that expert witnesses should only be allowed to be appointed and called by the court it self (as in by the judge so they and the jury could understand the technical details better) and not by either the defense or the prosecution.
They were not. It is never necessary to have 10,000 global variables. If you have 10,000 global variables you are systematically Doing It Wrong. (That's not to say it's uncommon. From my experience I strongly suspect that it's a very common practice.) As one of the witnesses put it, quite correctly IMO:
"And in practice, five, ten, okay, fine. 10,000, no, we're done. It is not safe, and I don't need to see all 10,000 global variables to know that that is a problem,” Koopman testified.
Trying to justify this is like trying to justify not having a bug tracker. Which, BTW, they didn't.
> b) implemented correctly,
There's no way to check 10,000 global variables to see if they're implemented correctly, and that's the entire point.
> and c) out of how many variables in total?
That is completely irrelevant.
> they claimed that every software within the system can access them to me this sounds that your stereo or the rain sensor for the wipers can override data for the breaks,
This was the ECU, it only controls the engine, not the radio or the wipers. It has tasks for stuff like monitoring the engine and wheel speeds, the accelerator and brake pedal positions and controlling the fuel injection. And all of those tasks were only an extra header file and a typo away from stomping on one of the 10,000 global variables belonging to another task, but that isn't even the issue. The issue is that there is no way to trace the flow of data in the system because it's completely unstructured.
> but that might be true only if everything is running within a single application.
Welcome to the world of embedded RTOSs, where everything is running within a single application. It's not a PC. "Applications" aren't a thing. There's certainly no memory protection.
> Welcome to the world of embedded RTOSs, where
> everything is running within a single application.
> There's certainly no memory protection.
But in the end the important consequence is: Having everything in one address space encourages people to violate the concepts that memory protection between tasks on your PC typically enforces, e.g. tasks reading from, and writing to other tasks' data structures without proper synchronization; instead of using proper IPC mechanisms like queues. Which is probably what these 10'000 global variables were used for.
Dav3xor's Law -- Code Quality is Inversely Proportional to Risk.
Anecdotal evidence is anecdotal.
I read that as:
> This is a company whose products are high-velocity 1500kg chunks of steel zooming around in public, not a company that sells an intangible virtual good/service
---
Yes, I know software is historically poor with car companies, but we should still expect better. Let's not just lower our standards because of cynicism :-)
When an engineer builds a bridge, she has to personally sign off on the bridge, saying it's safe, and is risking not only her professional career, but I think she can also be jailed and held criminally liable if the bridge kills people due to negligence.
It blows my mind, at least, that no such thing exists for software.
I'm not asking if you think such a thing would be possible or not - I'm asking if you would accept an alternate means of getting what I think we both want.
- https://en.wikipedia.org/wiki/ISO_26262
There aren't any guarantees that they'll be useful, that they'll match the modern development processes in your language, that they'll fit your problem domain, etc.
Those standards are there primarily to make the publisher a buck--not to represent the codified wisdom of up-to-date practitioners in a field.
Until we've got a truly open-source standard for people to code against, we should stop wringing our hands about these things.
ISO, IEC, etc.
> There's no licensure body for software engineers who build software running your car, and therefore no accountability on a personal level.
MISRA, SCSC, etc.
If you use software to build a bridge, bridge standards should apply. If you use software to build a car, car standards should apply.
If you use software to build a fart app, fart app standards should apply. (Which frankly, don't have to be very high.)
Then you don't know the motor industry very much as it has very strict coding standards like ISO 26262, the code has to be audited internally and by certified 3rd parties with every release to meet the development cycle requirements of the standards. http://www.ldra.com/en/software-quality-test-tools/group/by-.... The industry also has specific coding standard for every language that is used in embedded systems like MISRA-C https://en.wikipedia.org/wiki/MISRA_C
http://www.detroitnews.com/story/business/autos/foreign/2015...