> It is funny people can't envision things breaking...

This is what enraged me about the Therac-25 design which ended up killing people. There's a whole report to read on the design, failure and follow up but to paraphrase the designers eliminated the physical locking mechanism and had this attitude that "oh it's electronic so it won't wear out and fail".

Therac-25 https://en.wikipedia.org/wiki/Therac-25

Software errors killing people with excessive radiation doses.

It's a bit sad to see it coming up to regularly. On the one hand it's a very classic example of programming bugs leading to injury and death. On the other hand it's so long ago that bringing it up so often makes it seem like it's the only good example of dangerous software. Software must be pretty amazing and safe that we have to keep bringing up an example from the late 80s.

More that software that is critical is written with some level of care, and then never touched again out of fear of breaking it. See all the stories of hospital machines running windows xp.

That actually has a lot more to do with drivers not being provided by manufacturers for newer operating systems

It is useful to have a canonical example. Shared understanding of the problem, etc.

It’s related to why memes exist.

Uh, no. We have plenty of examples, they just don't kill people that often, because some industries learned their lessons.

If you want recent one, 737 MAX, killed way more than Therac-25. Although it was as much fault of software as suits around it wanting to save a penny on training, because if pilots knew about how it exactly worked they could've circumvented it

The software on the MAX worked as designed/specified; unlike Therac-25 there was no bug in the critical path, it was a series of design and oversight failures pushed by business and cost cutting interests, and the actual accidents were triggered (though I wouldn't consider it causal) by hardware failure in one of the AoA sensors. There was a bug regarding displaying an AoA disagree warning to the pilots, which despite being known wasn't fixed by Boeing, but this wouldn't have actually changed anything about the plane's behaviour.

To the credit of systems engineers, I can't think of a recent high profile fatal accident that could be reasonably blamed primarily on software, but that's not so much because software is infallible, but because systems are designed to fail safe.

Correct me if I’m wrong but wasn’t there an overflow in the software if the aircraft climbed too steeply ?

I’m sure I read that

I don't think so? Maybe a bug of this form was found, but I'm sure nothing like that was involved in the crashes. The flight control software performed as it was designed to, it wasn't software that sent the trim wheels spinning, but a bad AOA sensor and a lack of proper safety analysis, training and procedures.

There was a bug that caused the AOA DISAGREE alert on the EICAS not to be displayed, because at some point someone misunderstood the requirement that the AOA indicator should be hidden if they didn't pay for the upgrade, but this was just an indication and wouldn't have affected control at all (though likely would have hinted the pilots to a more appropriate cause of action).

One could also consider the lack of cross-checking between the two flight computers and associated AOA sensors to be a bug, but that was how the system was intentionally designed, because AOA wasn't considered a flight-critical measurement in the system's safety assessment, so they didn't consider this required. A holistic safety analysis was never really done inclusive of MCAS though, and this requirement probably just followed on from 737NG and wasn't really considered (at least thoughtfully...) in MCAS' design.

The main bug was:

* each flight computer used its own angle of attack sensor with no way to detect failure. Craft had 2 sensors, but they were not used together (apparently that was extra paid option...) * pilots didn't know how the system worked or when it is active, so they were fighting against it

don't remember anything about overflow

> Software must be pretty amazing and safe that we have to keep bringing up an example from the late 80s.

Or perhaps this failure settle the argument about whether or not physical lockouts were necessary and due to regulations you can no longer rely solely on software?

> but to paraphrase the designers eliminated the physical locking mechanism and had this attitude that "oh it's electronic so it won't wear out and fail".

And it would have been entirely fine if there was electronic safeguards put between code and rest of the device, just like some stop lights have it (if control board sends green signal to both directions it fails out and doesn't allow that). Defense in depth and all that

Covered really well in episode 39 of Causality, one of my favorite podcasts:

https://engineered.network/causality/episode-39-therac-25/

Each episode focuses on a root cause analysis of a major engineering disaster. Presented in a dry but engaging way - he's a good presenter, but none of the "Radio Lab" style nonsense.

This reminds me a few years ago on a family holiday to malaysia I was sharing the room with my 10 year old cousin. I go downstairs to smoke suddenly his father calls me and tells me that my cousin called him crying in pitch black room as the lights went off. As he was lying on the bed reading a book motion censors did not detect any movement and the power cut off. Luckily he had his phone with him otherwise he would have been scarred for life. Why the fuck would they use motion censor for the light I would understand if they use it for the aircon or something but even then with the key card in the slot why would they set it like that.

> Luckily he had his phone with him otherwise he would have been scarred for life.

From the lights turning off? A ten year old?

Could be just a hyperbolic turn of phrase. The commenter may not be a native english speaker. The kid may have a developmental disability or a specific recent trauma related to this. Who fucking knows, it's none of our business. The story contributes to the discussion and makes its point either which way, what do you get from calling out this detail like this?

The parent may have a condition making him nitpicky, curious, and blunt (like Aspergers) or a specific professional or other curiosity related to this. Who fucking knows, what do you get from calling him out like this? See how it goes both ways?

Hehe, I very much do have a condition making me nitpicky and excessively curious! Thank you, your comment made me smile :)

FWIW I do have that condition as well, though it isn't usually called that these days.

What I gain from this is trying to move us away from comments that serve no purpose other than copy-editing each other and discouraging people from posting unless they can be confident in their adherence to the unwritten HN style guides. Which many people never can be, for various reasons.

If they had said that as part of a comment that overall served a different purpose I wouldn't have said anything. But it added nothing to this discussion except reinforcing the atmosphere that comments must be finely tuned to be taken seriously.

Yeah, the discussion could be kept more to the point. But it was a legitimate question for a sidenote - it's not like every subthread has to revolve around the original topic.

>FWIW I do have that condition as well, though it isn't usually called that these days

I know, never cared much for the politically and financially motivated rename, that imho blurs the condition across a larger area, instead of defining it better.

> Asperger was a member of a seven-member commission that was to categorize 200 disabled children according to their "educational ability" to decide their fate. 35 children were classified as "hopeless cases" and transferred to Spiegelgrund, where they all died. He was part of the legitimization of the murders and as an expert contributed to their categorization into "usefulness levels".

In this case since the guy it was named after would have killed me given the choice, I'm glad they renamed it. Good info about where you stand though, thank you.

>Good info about where you stand though, thank you.

You appear to stand in a worse place, implying people are Nazis because they're OK with using the traditional name for a condition, just because the person who did studied it had connections to them.

Your quick judgement of others, is worse than that - more Nazi-like in practical action, than some "association by name used for a condition" (which is no associatation at all). If I got power I'd be OK with some tainted names.

If you got power you'd classify people as enemies, or worse, based on such trivial matters as whether they prefer the older established name for a condition (and don't particularly care if we don't retroactively erase the person who discovered it from medical history for his crimes 80 years after the fact).

So a 10 year old in a foreign country in a room alone in pitch black dark for an hour or so won't get scared?. The room was pitch black we had checked in an hour or so ago so he was not even sure of where anything was in the room was. Though I confess part of the reason was his older siblings and cousins had been telling ghost stories the previous night.

You said "I go downstairs to smoke" and now you say "for an hour or so". I don't know your smoking habits, but isn't this a little unusual?

I don't think I've ever been in a "pitch black" hotel room. I'd bet there was light enough for him to start seeing just fine after five minutes.

The ghost stories, sure. But then he's scarred for life more by the ghost stories rather than by the lights turning off...

But the point of the anecdotal story was using automation wrongly why would you care about the turn of phrase I used

Sure agreed that automation is often pointless and more harmful than helpful. I'm just surprised you're making such a fuss about a ten year old in a dark room.

> I'm just surprised you're making such a fuss about a ten year old in a dark room.

Pretty sure that was just being used as an example to underscore a broader point. No need to nitpick.

why not switch off power in breaker box for all rooms besides kitchen? surely they must have breaker in case there would be electrical fire or some repairs

edit: and now I'm 100% sure there are bots downvoting my comments, immediately downvoted less than minute from posting

That's not something most people want to do, might violate the Airbnb agreement, and who knows what else might go wrong when it came time to turn things back on? Maybe people just think it's a bad idea.

Maybe those people are two afraid of BS eventuallities? I have anxiety and wouldn't think twice of doing that...

surely I wouldn't care about some Airbnb agreement instead of sleeping with lights on, that's basically unusable apartment for me and breaks Airbnb agreement way more than trying to solve the issue if renter doesn't care to fix it immediately

not sure what should go wrong when you switch on the power again, blackouts happen

There are good reasons not to. A lot of apartments here have security devices which will call for assistance when the power is turned off. Then there are devices that expect power 24/7 like fridge. Also, since I was abroad, I relied on the Internet that was at the apartment that would be cut off if the power was turned off.

Also... you know... there are these funny little devices called switches that allow you to turn individual devices on and off without cutting power to entire apartment. Just saying...

Breaker boxes, at least were I am, are split in areas, that you can switch off independently. Switching the area were the lights were and leaving kitchen and router solves all your concerns except the security devices when power is off (which I personally never saw).

My first reaction would have been what OP suggested.

You'd be surprised how many older houses don't comply with current electrical codes.

And even the current code in CA doesn't require separate circuits for each room. They require separate circuits for different functionality. E.g. lights vs power plugs.

Even easier then, just turn off the lights.

Wouldn't that be... all of them? They were literally not build with code that didn't exist at the time. Why would that be surprising ?

You have obviously not been to the UK; breaker box will have a few illegible marker squiggles, most faded beyond reading, some with tape over and a second conflictibg squiggle. Even if you decode them then the fridge is just as likly to be on the hall as the kitchen

Same here. You can still trivially try the various switches and see if they cut off the area of the house you're interested it. If the fridge is on the same circuit as the lights you want to kill, there goes you plan. But otherwise, it's fine. In most AirBnB's and rented rooms for short stays the fridge is empty or just has some water/sodas anyway, it's not like there would be the family's food for the month..

Thank you. This seems to me like the common sense approach to solve this problem IRL, as opposed to in a spherical cow world. It will work in 99% cases. In the rest, one can sleep with the lights on, or cover them (if possible).

Unscrewing the bulb a couple turns used to be a great off switch.

Then Big Lighting ruined that by going to LED strips and what not.

I don't think I've ever seen a breaker box that was clearly and correctly labeled at any house that wasn't still on its first owner.

The first thing I do when renting a new apartment is map out the circuits to outlets and leave a map next to the breaker box. We have also consistently had illegible squiggles (and strange circuit layouts) in Canada

I have been working on the map for my house's circuits for 6 years. It's about 80% done.

Whilst some breaker boxes are nice, modern, and make sense... Others are like this [0] and terrifying.

[0] https://reddit.com/r/australia/comments/yq4hks

>A lot of apartments here have security devices which will call for assistance when the power is turned off

Some might, but I doubt they are a lot. None have such where I am for sure. People would need to turn power off for specific rooms/circuits or the whole thing once a year or so anyway (to do some electrical work, to change some light fixtures, etc). It also happens by itself if some machine overloads/there's a sudden surge. I've changed several rented houses, and it would ocassionally happen to all of them.

As for the fridge, he did say to leave the kitchen (or fridge including) circuit on.

> Some might, but I doubt they are a lot. None have such where I am for sure.

Just your subjective knowledge of your local area and class of home you normally experience.

Not everybody enjoys the security that western democracies provide (although US and couple other countries seem to be slipping behind). In most of the world people with wealth above standard have to actually take special, pretty expensive precautions to preserve their wealth (and in some places lives).

Here people install security to call security company whenever the alarm is tripped. Lack of power is immediately suspect (thieves like to cut power). The security company is notified by the automation and they call the owner for security code. If the owner does not give the security code within required time they will immediately dispatch their patrol. The owner also has special security code in case he is compelled to give one and this triggers a specially escalated response.

>Just your subjective knowledge of your local area and class of home you normally experience.

So, like yours? When you said "A lot of apartments here have security devices" did you qualify it as "in non western countries with the right balance of affording security services and intenterrupted mains power"?

>Not everybody enjoys the security that western democracies provide

Well, not everybody who doesn't enjoy "the security that western democracies provide" has money to pay for a security company - or even the luxury of continuous power that is not frequently cut anyway, either.

In the context though, in a house with automatic sensors and such, I'd consider my case more likely.

>Then there are devices that expect power 24/7 like fridge.

I documented a bit recently as in France we will potentially have 2h power extinction at grid level during this winter. Apparently you can have your fridge safely keeping your food for up to 4h, but you should not open it during that period obviously — although since I don’t have any radiator in my kitchen I’m rather confident it wouldn’t be that problematic in the middle of a winter that is announced especially cold.

> Apparently you can have your fridge safely keeping your food for up to 4h, but you should not open it during that period obviously

Kinda depends on fridge, altho sadly it's rare to see that number in manuals.

But one trick is to just take food that you want to eat anyway from the freezer and put it in fridge, the food will slowy defrost while cooling the fridge food. Just make sure water have somewhere to go

>A lot of apartments here have security devices which will call for assistance when the power is turned off.

that's quite rare and bad design if you can't go overnight without power

>Then there are devices that expect power 24/7 like fridge.

that's why i said to leave kitchen ON, not that Airbnb fridge on first night would contain anything requiring power anyway

> Also, since I was abroad, I relied on the Internet that was at the apartment that would be cut off if the power was turned off.

dunno about you, but when I sleep I don't use internet, but maybe you are able to disable some parts of brain and use internet while sleeping

>Also... you know... there are these funny little devices called switches that allow you to turn individual devices on and off without cutting power to entire apartment. Just saying...

Also you know maybe read the comment I'm replying to about faulty automatic switches impossible to switch off.

I thought HN readers pay more attention to what they answer to and the context, but after reading some replies to my comment I've lost all hope that this site is any better than Reddit.

Maybe they don't have breaker boxes in every room or a breaker for every room, in a central box. Is that a requirement in your country? My house has several separated circuits but not one per room.

And maybe all those people reading HN and clicking into the comments of this post are actually bots.

then just disable all power, what do you need while you sleep? nothing, maybe AC but no AC beats sleeping with lights on, other than that it's only fridge which would be empty on their first night anyway

obviously other more elegant solution would be unscrewing bulbs, but they may be not accessible

>only fridge which would be empty on their first night anyway

That's a bit of a weird claim. I'd say it's likely to be at its most full on the first night.

Do you have usually fridge in airbnb place filled with anything else than just drinks (which would be fine also without refridgeration) on first evening after coming?

Is the first thing you do in the afternoon after checking in airbnb place going to shop to buy tons of supplies to store them in fridge?

I'd think people have better things to do on the first evening than shopping for groceries besides something small for dinner (if any) and those few dinner things would be fine even without fridge or not worth sleepless night with lights on.

Do you not eat breakfast? Or meat?

I usually pack some snacks or just buy something small for first dinner and breakfast, only later go to do proper shopping.

Because fucking with the electrical system in someone else’s house is usually frowned on.

Did you consider the insulin fridge in the garage you just shut off when you did that? How about the attic fan that keeps the place cool? The water softener that needed to do a recharge cycle. The electric vehicle plugged in that was waiting for night time trough to charge. etc, etc

> edit: and now I'm 100% sure there are bots downvoting my comments, immediately downvoted less than minute from posting

No, you’re just inconsiderate of people’s property.

maybe read the comment I'm replying to about guy in rented whole airbnb apartment with faulty motion sensors who had to sleep with lights on instead of switching off power in breaker box (or unscrewing bulbs if accessible), not sure why would anyone renting Airbnb apartment had any of those in rented apartment

you come out as completely ignorant of context who just gets angry for no reason

I did read it. It doesn’t change how inappropriate it is to mess with the breaker boxes in other people’s property. The appropriate response was to contact the host.

> you come out as completely ignorant of context

Says the commenter who didn’t follow the context.

I wouldn't at all be surprised if the AirBNB in question had the utility room locked up to prevent the guest tampering with things. In my experience its about even odds whether or not you'd even be able to access things like the breaker box, water heater, or even the router.

Not accessible breaker box sounds extremely dangerous and illegal.

A goodly number of AirBNBs are flying in the face of local ordinances against short term stays and the like, why not flip a bird at the fire marshal while they do?

Just turn it off at the fuse.

Some fixtures may support yanking a bulb.

> It is funny people can't envision things breaking...

By comparison the Clap switch is so simple that if it is quite at least you can sleep at night

Take out the bulbs.

A lot of modern light fixtures have LEDs built in to the gadget, no separate "bulb".