robryk @robryk@qoto.org
I enjoy things around information theory (and data compression), complexity theory (and cryptography), read hard scifi, currently work on weird ML (we'll see how it goes), am somewhat literal minded and have approximate knowledge of random things. I like when statements have truth values, and when things can be described simply (which is not exactly the same as shortly) and yet have interesting properties.
I live in the largest city of Switzerland (and yet have cow and sheep pastures and a swimmable lake within a few hundred meters of my place :)). I speak Polish, English, German, and can understand simple Swiss German and French.
If in doubt, please err on the side of being direct with me. I very much appreciate when people tell me that I'm being inaccurate. I think that satisfying people's curiosity is the most important thing I could be doing (and usually enjoy doing it). I am normally terse in my writing and would appreciate requests to verbosify.
I appreciate it if my grammar or style is corrected (in any of the languages I use here).
Joined Nov 2020
Your shirt is obviously an improvised weapon usable for strangling and smothering! Your blood is a liquid, please remove all of it before coming inside! Your shoe is a projectile (remember Bush?) -- you can't have those. Your phone is an artificial noisemaking device, so it also stays out. /s
I'm really perplexed by umbrellas -- so what should people do if it's raining? I'm also amused by "batteries", insofar the word lost its original meaning and is used to refer to single cells too, and by the ban on monopods and tripods, but seemingly not bipods (except they are also improvised bats and projectiles).
If the train was something like 13hrs it might actually have been competitive if it was a night train. (I'm pointing this out, because there's a range of travel times where travel taking longer might not be a bad thing and might be actively preferred by many people.)
robryk
boosted
In the process of debugging a NUMA first-touch problem, I accidentally found my simulation becomes significantly faster when it's running on garbage data without memset() - even on non-NUMA systems... What?! Does the kernel provide a fast-path for uninitialized memory that I've never heard of?
"a read from a never-written anonymous page will get every page copy-on-write mapped to the same physical page of zeros, so you can get TLB misses but L1d cache hits when reading it."
Yes... #hpc@wortfechterin @jobook @boran_gregovic
Das ist nicht wirklich die Frage von der eingdeutigen Identifizierung, sondern von geprüfter Identifizierung. Wenn man ein persönliches Ticket kauft (ich glaube alle DB E-Tickets waren seit lange persönlich, oder nein?), muss man natürlich sich identifizieren. Aber es ist fraglich, ob das irgendwelche Zusicherung benötigen soll: man muss sich bei der Ticketkontrolle schlussendlich irgendwie ausweisen.
TIL that a traffic warden standing with your back or front to you does not necessarily mean "stop" in Switzerland: https://www.fedlex.admin.ch/eli/cc/1979/1961_1961_1961/de#chap_7
I also didn't know that and am wondering how widespread that is (both geographically and for CS-adjacent departments like ones that teach robotics or computational math).
In addition to that, they also:
- have mechanics to answer questions (for example, it's sometimes not obvious if a bike can take panniers),
- try to figure out if any of the bikes are stolen beforehand,
- deal with actually selling the bike so the seller doesn't need to be there the whole day (they just drop off the bike in the morning and pick up money or bike in the evening),
- have some sort of setup where you can take one of the bikes for a test ride.
In general it seems to me that a large part of the reason why that feels very nice (from a buyer's perspective at least) is that they remove incentives to be dishonest, so that everyone taking part can just be calm, trusting, and assume the same of others and won't be harmed by that. On the other hand, I think that a large reason why this became a major thing (there are nonspecialized flea markets and you can buy/sell bikes there too) is in large part that it's very hassle-free for sellers.
Regarding the place, Zurich has a few squares in the city center, which tend to get used for such things (I'm actually not sure how that works formally tbh). Sadly that's probably one of the larger problems with setting something like that up in the US (or am I very off?).
To give you a order of magnitude estimate, there is one such flea market organized every month Spring-Autumn in Zurich (pop. ~700k city, ~1.5M agglo) and I'd estimate that there is a bit below 1000 bikes there ~each time.
Something of this shape happens in an organized fashion in larger cities in Switzerland: an association of bike users (https://www.pro-velo.ch/) organizes bike flea markets (as in, the bikes being sold aren't theirs -- they only provide organization). Apart from some amount of inspecting of the bikes for sale (I'm not sure how thorough) what they also do is get mechanics to answer sellers' questions.
TBF I would really like something that transcribes podcasts or videos and maybe removes/deemphasizes[1] the speech mannerisms that are helpful for speech but not for text (e.g. some kinds of repetitions). I haven't seen yet anything that would do even the first part well totally automatically, but I think both parts are much closer than other things people dream of AI doing.
[1] in text, one can use various font style tricks to do so
Hm~ is it about those salts decomposing into something else in solution at high temperature?
Why do PWR reactors use boric acid, as opposed to some random salt of boron? Apparently boron salts are often well soluble, from the nuclear POV we only care about boron being present, and I'd expect salts to cause fewer chemical problems due to their closer-to-neutral pH. In fact some random papers (https://inis.iaea.org/collection/NCLCollectionStore/_Public/28/034/28034575.pdf) describe tradeoffs involved in maintaining pH as boric acid concentration changes.
There clearly must be some reason why boric acid is preferred over any simple boron salt. What is it?
Can you expand on what you mean by boring? When I was a preteen I could find random websites with lots of circuit diagrams for simple things someone found useful, Seaview fanfiction, and various very esoteric topics. My impression is that finding as satisfyingly in-depth descriptions, especially of niche topics, is now harder.
Jeśli dobrze rozumiem https://www.gov.uk/apply-for-photo-id-voter-authority-certificate to można dostać dokument który działa znając tylko czyjś "National Insurance Number". Czy jest to z jakiegoś powodu trudniejsze do oszukania niż wersja w której komisji możnaby podać ten numer?
If you are still curious about the mechanism of the weirdness: Can you tell how? (Did it get pushed to it? Did it fetch it? From A or from C?)
My very wild hypothesis is that for some reason B doesn't consider these messages (I forgot Matrix's term for nodes-in-the-room-history-dag) valid. Perhaps A changed its mind about its signing key? But I don't know why B haven't fetched them from C, trusting them because C considers them valid. I will need to reread how validity determination works, but now I need to sleep, so it has to wait until tomorrow. (I realized I don't get how you can at the same time prevent C from potentially impersonating A's users and at the same time accept nodes from C that mention a node from A that appears invalid as a parent.)
I wonder what happens if A keeps changing its mind about what its signing keys are.
How do you know that it didn't get federated directly from A to C? (Even if it did, it would still be a very weird failure mode.)
Huh, I'm very surprised that you find this line odd (I don't think I've seen this opinion in the past). I would appreciate if you answered a question or two so that I can understand it better (but do understand if you don't wish to).
The reason I find this line very natural is that I think in terms of which node is intended to be able to speak for which entities, especially that those entities are named in a way to remind us of that relation (domain in URLs, domain/instance part of a fedi ID). Do you think that it makes more sense to keep track of a more vague trust (as in, "that node is rather trustworthy") in general, that the mapping between nodes and entities is insufficiently natural, or something else I can't easily see?
I enjoy things around information theory (and data compression), complexity theory (and cryptography), read hard scifi, currently work on weird ML (we'll see how it goes), am somewhat literal minded and have approximate knowledge of random things. I like when statements have truth values, and when things can be described simply (which is not exactly the same as shortly) and yet have interesting properties.
I live in the largest city of Switzerland (and yet have cow and sheep pastures and a swimmable lake within a few hundred meters of my place :)). I speak Polish, English, German, and can understand simple Swiss German and French.
If in doubt, please err on the side of being direct with me. I very much appreciate when people tell me that I'm being inaccurate. I think that satisfying people's curiosity is the most important thing I could be doing (and usually enjoy doing it). I am normally terse in my writing and would appreciate requests to verbosify.
I appreciate it if my grammar or style is corrected (in any of the languages I use here).
Joined Nov 2020
