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Based on the CNBC article, here's my understanding. Someone please correct me if I'm wrong, because this sounds... really bad with safety implications that are

Based on the CNBC article, here's my understanding. Someone please correct me if I'm wrong, because this sounds... really bad with safety implications that are not at all related to self-driving. 1. Tesla vehicles are drive-by-wire. 2. The missing component is a backup chip in the steering system. 3. The backup was excluded in a time frame that precluded robustness testing. Are any of these items wrong? Because, if not, characterizing this as "oh well you have to bring your car in if you want our full self-driving magic" seems like a massive PR spin and a huge disservice to Tesla owners who every day bet their lives on Tesla's drive by wire system. (Missing/not using a backup chip on a safety-critical system is exactly what caused the failure of the flight characteristic modification software on the 787-MAX. Missing backups was also identified as a possible root cause in the Toyota deaths. Backups are important, and the history of safety-critical systems that ignored the need for backups is littered with human bodies. Shit happens at scale.)

vardump 4y ago
Tesla vehicles are not drive by wire, but have a direct mechanical linkage.
- frosted-flakes 4y ago
  Of course it's drive-by-wire, it's an electric car. How could it possibly be drive-by-cable? Cars have been largely drive-by-wire since the early 2000s.
  - ternus 4y ago
    The confusion here is between throttle-by-wire (which, as you point out, is now ubiquitous) and steer-by-wire, which Teslas still aren't. There was some hope that the newest yoke-equipped Model S would be, but my understanding is that it's still a direct mechanical link, i.e. wheels still turn if you move the steering wheel when the car is off. The driver-assist functions use motors to move the steering linkage.
    - throwawaygh 4y ago
      Right; the whole conversation re: "what is drive by wire anyways?" is a massive red herring. That's really my bad. The operative question is just "what happens if the primary chip fails?" If the answer is "nothing bad, yet, but maybe something bad when we ship FSD" then Tesla's approach here seems reasonable (modulo not informing customers, which will probably catch them a fine in at least some of these jurisdictions, but in my book is more like a "mild breach of commercial contract" issue than a "fundamental consumer rights" issue). If the answer is "something bad" then this is a big deal and could be bad news for Tesla.
    - frosted-flakes 4y ago
      Wouldn't steer-by-wire that reduce steering feedback even more? Compared to my old (somewhat unreliable) Jetta with hydraulic power steering, every electric steering-assist car I've driven has terrible steering feel, like I'm driving an RC car. I feel so disconnected from the road, as if I'm merely aiming the car rather than actually driving it.
  - PlanckMeasure80 4y ago
    It can be drive by cable in a multitude of ways. One way is that your foot moves a plug in and out that physically connects the batteries to the motor. There are other ways that are real, too.
- throwawaygh 4y ago
  Is that really true? I know that there's a mechanical connection, but the existence of a mechanical connection doesn't necessarily mean that the system is not effective drive by wire (for the purpose of reasoning about system safety). I guess the operative question is: if the controller fails, what happens? If the answer is "loss of operator control", then saying that the car isn't drive by wire is the worst type of "technically true". Just like it was, in a silly sort of way, technically true that the 787-MAX's flight characteristics weren't changed in a way that required retraining... What is the safety-critical use case of the steering column controller? Just interrupting the ADAS?

vardump 4y ago

Tesla vehicles are not drive by wire, but have a direct mechanical linkage.

frosted-flakes 4y ago
Of course it's drive-by-wire, it's an electric car. How could it possibly be drive-by-cable? Cars have been largely drive-by-wire since the early 2000s.
- ternus 4y ago
  The confusion here is between throttle-by-wire (which, as you point out, is now ubiquitous) and steer-by-wire, which Teslas still aren't. There was some hope that the newest yoke-equipped Model S would be, but my understanding is that it's still a direct mechanical link, i.e. wheels still turn if you move the steering wheel when the car is off. The driver-assist functions use motors to move the steering linkage.
  - throwawaygh 4y ago
    Right; the whole conversation re: "what is drive by wire anyways?" is a massive red herring. That's really my bad. The operative question is just "what happens if the primary chip fails?" If the answer is "nothing bad, yet, but maybe something bad when we ship FSD" then Tesla's approach here seems reasonable (modulo not informing customers, which will probably catch them a fine in at least some of these jurisdictions, but in my book is more like a "mild breach of commercial contract" issue than a "fundamental consumer rights" issue). If the answer is "something bad" then this is a big deal and could be bad news for Tesla.
  - frosted-flakes 4y ago
    Wouldn't steer-by-wire that reduce steering feedback even more? Compared to my old (somewhat unreliable) Jetta with hydraulic power steering, every electric steering-assist car I've driven has terrible steering feel, like I'm driving an RC car. I feel so disconnected from the road, as if I'm merely aiming the car rather than actually driving it.
- PlanckMeasure80 4y ago
  It can be drive by cable in a multitude of ways. One way is that your foot moves a plug in and out that physically connects the batteries to the motor. There are other ways that are real, too.
throwawaygh 4y ago
Is that really true? I know that there's a mechanical connection, but the existence of a mechanical connection doesn't necessarily mean that the system is not effective drive by wire (for the purpose of reasoning about system safety). I guess the operative question is: if the controller fails, what happens? If the answer is "loss of operator control", then saying that the car isn't drive by wire is the worst type of "technically true". Just like it was, in a silly sort of way, technically true that the 787-MAX's flight characteristics weren't changed in a way that required retraining... What is the safety-critical use case of the steering column controller? Just interrupting the ADAS?