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Car allergic to vanilla ice cream (2000)

cs.cmu.edu

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Re: Car allergic to vanilla ice cream (2000)

#371

Post by lamename »

nvy wrote: post #369
jjbinx007 wrote: post #49

We had a similar problem at work in the late 90s. A member of staff reported that their mouse would stop working between certain hours of the day. It had apparently been okay in the morning, stopped working over lunchtime then started again later. On some days it would work perfectly all day long, but on others it would stop working between those hours. The biggest clue was it would always work perfectly on overcast…

Your car repeatedly doesn't start so instead of taking it to the shop, you... write a letter to the CEO of Pontiac who not only actually reads the letter but also personally dispatches an engineer to waste a week going out for ice cream? And Pontiacs have a known vapor lock design flaw that only you, the letter writer, are experiencing? And you've only experienced it on your ice cream runs? And you've never got the v…

While I appreciate your point, I think anyone who has spent sufficient time troubleshooting complex systems has dealt with similar types of problems, and can grasp the _spirit_ of the story.

In fact, I'd argue the quaint style of the story does geeks a favor: if it's appealing to normies, maybe they'll appreciate us technical folks' perspective a little more.

Re: Car allergic to vanilla ice cream (2000)

#372

Post by moduspol »

timmorgan wrote: post #146

My son's laptop screen kept shutting off while he was playing American Truck Simulator. His truck would drive off the road while the screen was black. Every time I played on his laptop, this did not happen. He swore he was cursed. This went on for many days, with many instances where it would happen for him but not for me. Then one day I just sat and observed him while he played, looking for any difference. That's wh…

This used to hit us sporadically at my university's help desk. It'd also happen if you have one MacBook open on top of a closed one. The magnet could easily line up and it'd shut the screen off.

Re: Car allergic to vanilla ice cream (2000)

#373

Post by LazyMans »

jonhohle wrote: post #222
jjbinx007 wrote: post #49

We had a similar problem at work in the late 90s. A member of staff reported that their mouse would stop working between certain hours of the day. It had apparently been okay in the morning, stopped working over lunchtime then started again later. On some days it would work perfectly all day long, but on others it would stop working between those hours. The biggest clue was it would always work perfectly on overcast…

When it’s sunny, my wife’s car can’t open the garage door, and my car requires getting extremely close. Once the sun goes down, we can both open the door from the street. It turns out our solar panels (or the optimizers, or the inverter) emit radio frequencies that interfere with our garage door opener. When the sun is out and they are producing energy, the interference is stronger than the homelink garage door opene…

If you get a SDR, you can watch the interference and try things to help reduce it. An SDR should be like $20 and you plug it into a computer

Re: Car allergic to vanilla ice cream (2000)

#374

Post by _drimzy »

Ah, reminds of my first car. I got a new Corolla and went on my merry way. But on the third day I found the steering stuck and extremely hard to maneuver. Scared the heck out of me, so I went back to the dealership. They inspected the car and informed me the next day that there was nothing wrong with it and asked me to pick it up. I drive out of the parking lot, and again the steering gets stuck, and I just circle around and give them the car back, showing the live problem. They inspect it another day, and aren't able to find anything wrong, and ask me to pick it back up. Sure enough, I haven't even gotten to my home yet and the problem reappears, so I drive it back to the dealership. This time they open up the car, the steering wheel and changed somethings in it and asked me to pick the car back up. Took me 4 mins of driving to land back in the same problem after which I made them refund my money.

I decided to shelve a few extra bucks and purchased a Camry from the same dealership. The second day while I was parking my new Camry, I found the same issue of the steering wheel getting stuck all over again, with this new car. So this was surely a me-problem, and not the car problem. After some analysis I relaized that I was turning off the car at red lights, without shifting to park. So when I turned it back on, the steering would lock itself. But if I shifted to park first then it would work perfectly!

Re: Car allergic to vanilla ice cream (2000)

#375

Post by ciabattabread »

Animats wrote: post #227
lxgr wrote: post #193

Earlier quoted context omitted.

Having had to debug many of such cable issues in the past, it's baffling to me that cable companies aren't proactively monitoring for things like this. They have all the data available on their end, as far as I can tell! (Unless DOCSIS modems somehow don't have a standard "signal receive report" functionality?)

Telcos used to monitor their copper outside plant for moisture. This was called Automatic Line Insulation Testing in the Bell System. The ALIT system ran in the hours before dawn. It would connect to each idle line, and apply, for tens of milliseconds, about 400 volts limited to very low current between the two wires, and between each wire and ground, measuring the leakage current. This would detect moisture in the c…

Ah, so that's why there were always nitrogen tanks on NYC sidewalks.

Re: Car allergic to vanilla ice cream (2000)

#376

Post by zmmmmm »

tantalor wrote: post #150
maweaver wrote: post #34

> Moral of the story: even insane-looking problems are sometimes real. To me the moral of the story (and my experience) is: user's problems are usually real, but don't trust their ability to diagnose the actual cause.

There's a big difference between the proximate cause and root cause. Proximate cause: buy vanilla ice-cream Root cause: vapor lock The letter didn't assert that the ice cream was the root cause, but made it very clear it was the proximate cause. The Pontiac President, and the person who wrote that "moral of the story", may have confused the two. But the engineer in the study didn't.

you can also frame it around correlation vs causation

Re: Car allergic to vanilla ice cream (2000)

#377

Post by AceJohnny2 »

ot1138 wrote: post #357
AceJohnny2 wrote: post #271

Earlier quoted context omitted.

By coincidence, I have witnessed this just last night. No details will be provided to protect identity, I'll just say you probably heard of the company. It's staggering.

What industry?

manufacturing.

Re: Car allergic to vanilla ice cream (2000)

#378

Post by Animats »

swores wrote: post #307
Animats wrote: post #227

Earlier quoted context omitted.

Telcos used to monitor their copper outside plant for moisture. This was called Automatic Line Insulation Testing in the Bell System. The ALIT system ran in the hours before dawn. It would connect to each idle line, and apply, for tens of milliseconds, about 400 volts limited to very low current between the two wires, and between each wire and ground, measuring the leakage current. This would detect moisture in the c…

Great comment, thanks! (I've sent a quick email suggesting it be added to https://news.ycombinator.com/highlights :)

If you're really into telephony history, the Internet Archive has "The History Of Engineering and Science in the Bell System" (3 volumes) online.

If you have to build reliable distributed systems, it's worth understanding how this was done in the electromechanical era of telephony, where the component reliability was much worse than the system reliability. "Number 5 Crossbar"[1] is worth reading, but hard to follow if you have no idea how telephone switching worked and are unfamiliar with the terminology.

Number 5 Crossbar, in current terms, was a collection of microservices. There was a big, dumb switch fabric, and "markers" which told it what to connect. Other microservices included trunks, originating registers (which listen to incoming dial digits), senders (which sent dial digits to the next switch), billing punches (which recorded toll call data for later billing), translators (which held routing tables), and trouble recorders (which logged errors.) Central offices had at least two of each resource, for redundancy. Resources were "seized" as needed from resource pools, with a hardware timeout and alarms to prevent resource lockup. If something went wrong in setting up a call, it was retried once, using different resources. If it failed on the second try, the caller got a fast busy and there was an alarm and a trouble recorder dropped a trouble card. Markers did not have persistent state. They started each call with a reset. So they could not get stuck in a bad state.

In the entire history of the Bell System, no electromechanical switching office was ever down for more than 30 minutes for any reason other than a natural disaster or a fire. It's worth understanding how they did that.

[1] https://telephoneworld.org/mdocs-posts/number-5-crossbar-sys...

Re: Car allergic to vanilla ice cream (2000)

#379

Post by fomine3 »

kup0 wrote: post #149

This reminds me of the "my monitor blinks every time I sit down in my office chair" turning out to be EMI spikes from the gas lift affecting the signal traveling on monitor cables. A DisplayLink KB article even mentions it (and the associated white paper about the issue), stating: Surprisingly, we have also seen this issue connected to gas lift office chairs. When people stand or sit on gas lift chairs, they can gene…

Exact same case happens for me except my chair doesn't have gas lift. It's weird.

Re: Car allergic to vanilla ice cream (2000)

#380

Post by dylan604 »

bandyaboot wrote: post #370
dylan604 wrote: post #38

Earlier quoted context omitted.

i learned that these things typically are grounding issues. it usually came down to a single source of ground being a loose connection which is why it was intermittent. as a personal anecdote to this, as a first car as a teenager, i drove a GM/Chevy S-10 that one day started to have issues where all of the gauges on the dash would just go crazy and the lights would go on and off, and then suddenly just start working…

I think independent mechanics tend to opt for earning goodwill in this situation rather than charging fair value for a quick and easy fix. Objectively, he provided more value than someone who might have spent several hours of troubleshooting time, but customers don’t necessarily think logically about it. So it ends up being better for the mechanic to earn that goodwill rather than appear “greedy”.

Some do the freebies because that’s who they are, and the free publicity is just a secondary effect. Some do the freebie because they know the publicity as the primary reason. I feel like this experience was the former.
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