5 ms·

The vulnerability and the fix remind me of a chapter in Gödel, Escher Bach where Achilles gives the tortoise (or maybe the other way around) a record that, when

The vulnerability and the fix remind me of a chapter in Gödel, Escher Bach where Achilles gives the tortoise (or maybe the other way around) a record that, when played, destroys his record player. So fun to see that IRL.

SilasX 4y ago
That actually illustrates why it’s a bad analogy for communicating the concept: it’s not intuitive at all why record player could be destroyed by playing the right record — most have volume limits that make this very difficult in practice, and most people never see one even getting close enough to see the dynamics that would cause it to happen. And so it definitely doesn’t help communicate the broader idea that all formal systems (meeting some minimal criteria) should have a corresponding flaw. (I would have gone with a helicopter as the system but that would require domain familiarity.)
- bch 4y ago
  > I would have gone with a helicopter as the system but that would require domain familiarity Would you give it a try?
  - SilasX 4y ago
    Well, there isn’t much to add beyond the fact them being more prone to acoustic breakage. Helicopters are a nightmare for vibrations because you have to spin the rotor really fast and forcibly, risking over-stressing critical structural components if you excite them at their resonant frequency. They’re designed to operate at only one rotor speed because that’s enough of a headache in terms of preventing it from hitting resonant modes that the structure can’t handle. So for helicopters it’s much easier to imagine a pattern of rotor movement that will break the system — though again, getting the intuition down would require having modeled vibratory systems to see when they go out of control. But at least it’s more intuitive than record players, which work with much smaller vibrations and generally operate in moderate volume limits.
    - viscanti 4y ago
      I wonder why they didn't have Achilles give out a special rotor for a helicopter that would have caused the entire helicopter to break. It seems like a great analogy for people who have the required domain knowledge as well as think it would be reasonable for someone to gift someone else a helicopter rotor.
      - schoen 4y ago
        This reminds me of the Donald Duck cartoon in which for some reason some of the Duck family have acquired a steam calliope (kind of like a somewhat portable pipe organ), and are trying to figure out what to do with it. Whereupon they meet a strange hermit who lives in a cave, or something, and who says that he has absolutely everything he needs in life, and there is nothing they can offer him that would be of any value. Except for one thing. Of course, it turns out to be a steam calliope. Similarly, I suppose that, sometimes, when you really need a helicopter rotor, you really need a helicopter rotor!
      - SilasX 4y ago
        Did you miss that the analogy would have “rotor input” instead of a replacement rotor, and that I agreed it would require some domain knowledge, or is this just you adding toxic snark to look clever and discourage substantive contributions to these threads? In any case, the record player analogy is still unhelpful because it conveys no practical intuition about why a record might break its player — that doesn’t happen in practice. Unless you want to make a substantive remark by showing an everyday case where a normal record might come close to breaking a normal player.
        viscanti 4y ago
        Giving someone a rotor input seems unrealistic. I've never heard of someone gifting one and who would swap out a rotor input with one that would cause damage to the helicopter? I think readers would find that example too farfetched.
        4y ago
- hobs 4y ago
  It does explain it in the book in a fairly tortured way - its a perfect record player than plays things perfectly and can play anything and that makes it vulnerable. A worse record player would not be vulnerable.
HPsquared 4y ago
Zip drives had something like this. A malfunctioning drive could damage the removable discs in such a way that they would then damage other drives they were inserted into, then the cycle repeats... https://en.m.wikipedia.org/wiki/Click_of_death#Iomega_Zip_drives https://en.m.wikipedia.org/wiki/Click_of_death#Iomega_Zip_dr...
- samstave 4y ago
  OMG recall having a zip and 1 gig IOMEGA drive in your tower? and how cool you thought you were
  - 1shooner 4y ago
    Especially when that tower was a licensed mac clone SuperMac. I don't think our Jaz drives ever really worked.
  - Bud 4y ago
    I kinda always thought Zip was a kludge technology, and I thought I was way cooler because I used magneto-optical instead. (I kinda still do, because those discs are still working, 937 years later.)
- kmeisthax 4y ago
  The mechanism of damage is different. The faulty disks aren't vibrating the drive to death, the drive is head-banging[0]. Iomega cost-reduced the drives to a fault; removing a tiny piece of foam that is there specifically so that head-banging doesn't damage the drive head. Head-banging is an intentional feature on disk drives[1] to correct for read errors and get back to a known good state; so a corrupted disk would cause it to head-bang every time you tried to read from it. And since there was no cushioning on the drive rails each head-bang would misalign the drive... making it corrupt more disks! I'm not sure what the record player equivalent to this would even be. A very heavy stylus could damage the disc and carve into it, but there's no way you could have a disc permanently change the tracking weight of that stylus. [0] When a disk drive intentionally crashes its head against a mechanical limit to ensure position of that head in lieu of having an actual sensor [1] The most egregious case being the Apple ]['s 5 1/2" drives, which intentionally do this on every power-up.
dmd 4y ago
I mentioned this when this was posted last week. https://news.ycombinator.com/item?id=32507898 https://news.ycombinator.com/item?id=32507898
zzo38computer 4y ago
The Tortoise gave the phonograph record to the Crab. (The Crab had a record player which was claimed to reproduce any sounds.)
- ashton314 4y ago
  Thank you for the correction and expansion. I didn't have the book with me at the time so I was just going from memory. This must have been the section titled "Crab Cannon".

SilasX 4y ago

That actually illustrates why it’s a bad analogy for communicating the concept: it’s not intuitive at all why record player could be destroyed by playing the right record — most have volume limits that make this very difficult in practice, and most people never see one even getting close enough to see the dynamics that would cause it to happen. And so it definitely doesn’t help communicate the broader idea that all formal systems (meeting some minimal criteria) should have a corresponding flaw. (I would have gone with a helicopter as the system but that would require domain familiarity.)

bch 4y ago
> I would have gone with a helicopter as the system but that would require domain familiarity Would you give it a try?
- SilasX 4y ago
  Well, there isn’t much to add beyond the fact them being more prone to acoustic breakage. Helicopters are a nightmare for vibrations because you have to spin the rotor really fast and forcibly, risking over-stressing critical structural components if you excite them at their resonant frequency. They’re designed to operate at only one rotor speed because that’s enough of a headache in terms of preventing it from hitting resonant modes that the structure can’t handle. So for helicopters it’s much easier to imagine a pattern of rotor movement that will break the system — though again, getting the intuition down would require having modeled vibratory systems to see when they go out of control. But at least it’s more intuitive than record players, which work with much smaller vibrations and generally operate in moderate volume limits.
  - viscanti 4y ago
    I wonder why they didn't have Achilles give out a special rotor for a helicopter that would have caused the entire helicopter to break. It seems like a great analogy for people who have the required domain knowledge as well as think it would be reasonable for someone to gift someone else a helicopter rotor.
    - schoen 4y ago
      This reminds me of the Donald Duck cartoon in which for some reason some of the Duck family have acquired a steam calliope (kind of like a somewhat portable pipe organ), and are trying to figure out what to do with it. Whereupon they meet a strange hermit who lives in a cave, or something, and who says that he has absolutely everything he needs in life, and there is nothing they can offer him that would be of any value. Except for one thing. Of course, it turns out to be a steam calliope. Similarly, I suppose that, sometimes, when you really need a helicopter rotor, you really need a helicopter rotor!
    - SilasX 4y ago
      Did you miss that the analogy would have “rotor input” instead of a replacement rotor, and that I agreed it would require some domain knowledge, or is this just you adding toxic snark to look clever and discourage substantive contributions to these threads? In any case, the record player analogy is still unhelpful because it conveys no practical intuition about why a record might break its player — that doesn’t happen in practice. Unless you want to make a substantive remark by showing an everyday case where a normal record might come close to breaking a normal player.
      - viscanti 4y ago
        Giving someone a rotor input seems unrealistic. I've never heard of someone gifting one and who would swap out a rotor input with one that would cause damage to the helicopter? I think readers would find that example too farfetched.
        4y ago
hobs 4y ago
It does explain it in the book in a fairly tortured way - its a perfect record player than plays things perfectly and can play anything and that makes it vulnerable. A worse record player would not be vulnerable.

HPsquared 4y ago

Zip drives had something like this. A malfunctioning drive could damage the removable discs in such a way that they would then damage other drives they were inserted into, then the cycle repeats... https://en.m.wikipedia.org/wiki/Click_of_death#Iomega_Zip_drives https://en.m.wikipedia.org/wiki/Click_of_death#Iomega_Zip_dr...

samstave 4y ago
OMG recall having a zip and 1 gig IOMEGA drive in your tower? and how cool you thought you were
- 1shooner 4y ago
  Especially when that tower was a licensed mac clone SuperMac. I don't think our Jaz drives ever really worked.
- Bud 4y ago
  I kinda always thought Zip was a kludge technology, and I thought I was way cooler because I used magneto-optical instead. (I kinda still do, because those discs are still working, 937 years later.)
kmeisthax 4y ago
The mechanism of damage is different. The faulty disks aren't vibrating the drive to death, the drive is head-banging[0]. Iomega cost-reduced the drives to a fault; removing a tiny piece of foam that is there specifically so that head-banging doesn't damage the drive head. Head-banging is an intentional feature on disk drives[1] to correct for read errors and get back to a known good state; so a corrupted disk would cause it to head-bang every time you tried to read from it. And since there was no cushioning on the drive rails each head-bang would misalign the drive... making it corrupt more disks! I'm not sure what the record player equivalent to this would even be. A very heavy stylus could damage the disc and carve into it, but there's no way you could have a disc permanently change the tracking weight of that stylus. [0] When a disk drive intentionally crashes its head against a mechanical limit to ensure position of that head in lieu of having an actual sensor [1] The most egregious case being the Apple ]['s 5 1/2" drives, which intentionally do this on every power-up.

dmd 4y ago

I mentioned this when this was posted last week. https://news.ycombinator.com/item?id=32507898 https://news.ycombinator.com/item?id=32507898

zzo38computer 4y ago

The Tortoise gave the phonograph record to the Crab. (The Crab had a record player which was claimed to reproduce any sounds.)

ashton314 4y ago
Thank you for the correction and expansion. I didn't have the book with me at the time so I was just going from memory. This must have been the section titled "Crab Cannon".