Never trust a system that seems to be working • Hacker News Board

Re: Never trust a system that seems to be working

#181

Post by Lukas_Skywalker » Mon, Oct 17, 2022, 6:34 PM UTC

usrbinenv wrote: post #147

malloci wrote: post #128

Earlier quoted context omitted.

The hand is to mimic that of a traffic cop. When they want you to stop, they hold up their hand to indicate that you need to stop. It used to be that you had to know english in order to understand them as well...many of the signs used to use the words "walk" and "don't walk"

I guess my point is that it was still confusing. It took me a day or two to acquire a reflex. It obviously doesn't matter in the long run - you just get used to it - but I wonder why would US & Canada go a different way with regards to so many small things (think turn signals on cars being red for american cars as another example)? What would be the rationale? It's as if the western hemisphere was completely cut off…

Since this is HN, and I'm a pedant: reflexes can't be acquired, since they are not processed by the brain, but by the spinal cord, without involvement of the brain (e.g. pulling back the hand when touching a hot surface).

What you're thinking of is called procedural memory, which helps you perform a task without being consciously aware of it (hitting a fast baseball, looking left/right when crossing a street).

Re: Never trust a system that seems to be working

#182

Post by Darkphibre » Mon, Oct 17, 2022, 6:35 PM UTC

Reminds me a lot about the fascinating read of Knight Capital, and the $440M-in-28-min bug that lost them 75% of their equity.

Reminds me a lot about Knight Capital bug that cost them $440M in 28 min.

> Rogue orders seemed originated from the new RLP router code, but no one could pinpoint the bug.... they reverted to last-stable.... and even more trades executed than before.

https://www.henricodolfing.com/2019/06/project-failure-case-...

I remember a PDF that went into even greater detail, was a very good read.

Re: Never trust a system that seems to be working

#183

Post by ianferrel » Mon, Oct 17, 2022, 6:39 PM UTC

zoover2020 wrote: post #179

ianferrel wrote: post #159

Earlier quoted context omitted.

>I wonder why would US & Canada go a different way with regards to so many small things (think turn signals on cars being red for american cars as another example)? In many cases the US were the first to mass-manufacture things to some kind of standard, so the question is really: why did the rest of the world choose a different standard. Often they have a good reason (better design, maybe), but the US also has a good…

And standards don't adapt? To me this feels wrong and backwards

They do sometimes.

Like, the WALK / DONT WALK crossing signals that were around in my youth were slowly replaced with the HAND / WALKING PERSON ones, I'm sure because they're better for people who don't read English.

But also there is a cost to change, and it's often not worth doing if the benefit from the new system or standard isn't a lot better than the old.

Re: Never trust a system that seems to be working

#184

Post by randomdata » Mon, Oct 17, 2022, 6:42 PM UTC

zoover2020 wrote: post #179

ianferrel wrote: post #159

Earlier quoted context omitted.

>I wonder why would US & Canada go a different way with regards to so many small things (think turn signals on cars being red for american cars as another example)? In many cases the US were the first to mass-manufacture things to some kind of standard, so the question is really: why did the rest of the world choose a different standard. Often they have a good reason (better design, maybe), but the US also has a good…

And standards don't adapt? To me this feels wrong and backwards

They do when there is good reason, but there isn't always good reason.

In fact, a theoretically better standard could actually be worse in some situations if people are accustomed to a different standard. Imagine if America had settled on red for go and green for stop, and then tried to change the standard to match the rest of the world. It would be a calamity as some drivers continued to adhere to the old standard that they knew.

Stop signs were originally yellow, so such a change isn't unprecedented, but in that case they also contained the word STOP so the colour wasn't critical to understanding the sign. Standards can more easily change when there is backwards compatibility available. More recently, some jurisdictions have started adopting traffic light shapes (square = stop, diamond = caution, circle = go) but retain coloured lights for backwards compatibility.

Re: Never trust a system that seems to be working

#185

Post by ncmncm » Mon, Oct 17, 2022, 6:45 PM UTC

No post body was provided.

Re: Never trust a system that seems to be working

#186

Post by civilized » Mon, Oct 17, 2022, 6:48 PM UTC

Statisticians learned long ago that "missing" needs to be treated special. It should be either an entirely separate signal or a "sentinel value" riding on the existing signal that everyone knows and couldn't possibly be a normal operation value. Which is why sentinel values are usually a huge bunch of 9's or the maximum possible value of the field or something.

Interesting that the sentinel value is zero in this case. In data analysis that's usually a terrible sentinel value, but here it's the most practical one.

Re: Never trust a system that seems to be working

#187

Post by mschuster91 » Mon, Oct 17, 2022, 6:51 PM UTC

lisper wrote: post #84

adrian_b wrote: post #72

Earlier quoted context omitted.

This happens because the real insulators are better approximations of ideal insulators, than real conductors are approximations of ideal conductors. In electrical circuits made with normal conductors and insulators, e.g. copper wires and organic polymer insulators, it is possible to ignore the currents that branch from the wires and close through the insulators, because they are extremely small (e.g. in the femtoampe…

I have a bachelors degree in electrical engineering and work experience in hardware design and in the back of my mind I've always known this to be true, but this is the first time in my life I've ever heard anyone say this explicitly. EE pedagogy is badly broken in places.

> EE pedagogy is badly broken in places.

Generally, the biggest problem with math, physics and chemistry is that if you miss just one lesson (no matter if you physically miss it, or in worst case miss out understanding a concept for a couple minutes), you can easily end up "left behind" for years. With history, arts, languages, a number of computer science topics or most of biology you can either skip out on a certain subject or catch up easily on your own, but not getting a specific part in math/physics/chemistry and lacking the resources to follow up is setting oneself up for exponential learning gap later on.

The societal problem is that we've not set up schools or universities to deal with this "failure mode". Privileged kids can have after-school teaching or siblings helping out, but most will sooner or later resign and hate these subjects for the rest of their lives - and that is incredibly sad.

Re: Never trust a system that seems to be working

#188

Post by serf » Mon, Oct 17, 2022, 6:53 PM UTC

drewtato wrote: post #154

spillguard wrote: post #140

Side note, does anyone know why the author has written "F*ctorio" instead of "Factorio"?

https://twitter.com/Foone/status/1581662557470806017

the problem is that while it also breaks search for the inflammatory assholes that want to ruin everyone's day, it also breaks search for everyone else.

it's a strange problem, to be sure. "I want to speak publicly about something in the market-place square, but in such a way as to avoid the nay-sayers and rabble-rousers.' -- this seems like a problem that was fixed in ye days' of olde by forming secret collectives and 'meeting down by the docks', I guess that's akin to what federated services offer?

note : I find federated social networks to have the same flaw, it's my belief that good things should be archived and catalogued for the public good -- so I have a hard time getting behind the idea of federated spaces that are protected from archival efforts -- but I do acknowledge that curation of a group is one of the best ways to reduce harassment.

Re: Never trust a system that seems to be working

#189

Post by lostcolony » Mon, Oct 17, 2022, 6:54 PM UTC

Arainach wrote: post #150

kevincox wrote: post #131

Earlier quoted context omitted.

I may be biased because I am used to the hand but I find the walk and hand shapes are very distinctive compared to the walk and stand. However green on walk would be nice.

Clearly everyone should adopt the (East) Berlin standard: https://en.wikipedia.org/wiki/Ampelm%C3%A4nnchen Very visually distinct, walking and standing, and green/red.

I find them far less distinct than a walking person and a hand...and if I was colorblind that would be a large problem for me (and colorblindness was the reason for distinguishing the shape in the first place, so makes sense to have very different shapes rather than both "stick figure with hat").

Re: Never trust a system that seems to be working

#190

Post by BenjiWiebe » Mon, Oct 17, 2022, 6:55 PM UTC

adrian_b wrote: post #72

mschuster91 wrote: post #52

Earlier quoted context omitted.

Current flow is independent of wire length, the sender only has to turn up the voltage high enough to overcome the wire resistance.

This happens because the real insulators are better approximations of ideal insulators, than real conductors are approximations of ideal conductors. In electrical circuits made with normal conductors and insulators, e.g. copper wires and organic polymer insulators, it is possible to ignore the currents that branch from the wires and close through the insulators, because they are extremely small (e.g. in the femtoampe…

You will also get voltage drops from the sensors using power along your current loop as well, no? Whereas current will be the same along the entire loop all the time.