5 ms·

The probability of a bit flip enabling the leaf-replacer logic instead of causing a weird heisenbug and just crashing the camera app is astronomically low.

layer8 5y ago
Just crashing the camera app won’t end up on Twitter and HN though.
DSMan195276 5y ago
Yeah but how many iPhone pictures are taken every day? I'm not saying I'm convinced, but even something with 1/1,000,000,000 odds isn't really out of the question for an action that must happen at least millions of times a day.
- 1_player 5y ago
  Your probability estimate is off by a dozen orders of magnitude. As a back of the napkin estimate, an iPhone with 8GB has 64 billion bits that can be flipped. One bit flip per week per user would already be extremely bad, as it would mean on average one random crash or case of data corruption per week. If you suppose the bit flip happens in the CPU registers, the number of state changes on a modern CPU is so incredibly huge that a random bit flip doesn't just cause a memory load from a wrong address or a crash is, again, much less probable than 1/1e9 odds, by a lot. And as explained in my other comment, you'd have to show that this behaviour can be expressed in one bit. Is there a bit anywhere in the iOS hardware and software that by changing from 0 to 1 can run a code path that replaces your face with a leaf? I doubt that. I stand by Occam's razor. This happens because it's a bug introduced by its programmers rather than a random gamma ray that turned a bit to 1.
  - dannyw 5y ago
    also most cpus have ecc on registers.
    - 1_player 5y ago
      I didn't know that, but it makes a lot of sense.
Gigachad 5y ago
There are billions of iphone users taking photos every day. Astronomically rare things happen regularly.
- 1_player 5y ago
  Yes, bit flips are quite rare already, in the grand scale of things. So a bit flip that causes that specific behaviour is exponentially rarer. And you have to prove that there actually is one bit that, when changed, causes faces to be replaced by background objects, in this case leaves.

layer8 5y ago

Just crashing the camera app won’t end up on Twitter and HN though.

DSMan195276 5y ago

Yeah but how many iPhone pictures are taken every day? I'm not saying I'm convinced, but even something with 1/1,000,000,000 odds isn't really out of the question for an action that must happen at least millions of times a day.

1_player 5y ago
Your probability estimate is off by a dozen orders of magnitude. As a back of the napkin estimate, an iPhone with 8GB has 64 billion bits that can be flipped. One bit flip per week per user would already be extremely bad, as it would mean on average one random crash or case of data corruption per week. If you suppose the bit flip happens in the CPU registers, the number of state changes on a modern CPU is so incredibly huge that a random bit flip doesn't just cause a memory load from a wrong address or a crash is, again, much less probable than 1/1e9 odds, by a lot. And as explained in my other comment, you'd have to show that this behaviour can be expressed in one bit. Is there a bit anywhere in the iOS hardware and software that by changing from 0 to 1 can run a code path that replaces your face with a leaf? I doubt that. I stand by Occam's razor. This happens because it's a bug introduced by its programmers rather than a random gamma ray that turned a bit to 1.
- dannyw 5y ago
  also most cpus have ecc on registers.
  - 1_player 5y ago
    I didn't know that, but it makes a lot of sense.

Gigachad 5y ago

There are billions of iphone users taking photos every day. Astronomically rare things happen regularly.

1_player 5y ago
Yes, bit flips are quite rare already, in the grand scale of things. So a bit flip that causes that specific behaviour is exponentially rarer. And you have to prove that there actually is one bit that, when changed, causes faces to be replaced by background objects, in this case leaves.