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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

TIL that a traffic warden standing with your back or front to you does not necessarily mean "stop" in Switzerland: fedlex.admin.ch/eli/cc/1979/19

Hm~ is it about those salts decomposing into something else in solution at high temperature?

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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 (inis.iaea.org/collection/NCLCo) 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?

Ah, PSA: if you do actually collide with a bat, check very thoroughly whether (a) you got scratched in any way (b) you got your face in contact with the bat. If either happened, wash the scratch/your face thoroughly and urgently visit a doctor due to the risk of rabies.

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I think I nearly collided with a bat today. I was riding a bike along Sihl just north of Sihlcity (the path is between a small forested hill and a river with a highway overpass over it; it's sparsely lit with streetlamps) and saw (~single frame only, because of timing wrt my blinking) a dark concave-sided diamond shape in front of me and felt a gust of wind.

It's not that surprising, given that a bit further north friends of mine would semi-regularly notice bats over the rive (and I did once or twice), but the near collision is surprising given my very predictable motion.

robryk boosted

“How do you accidentally run for President of Iceland? | by Anna Andersen”

Glad somebody wrote about this because it’s an objectively hilarious UX case study

(And they just announced that eleven people managed to get the requisite number of endorsements in time) uxdesign.cc/how-do-you-acciden

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So ...let's face it. A LOT of folks in tech circles are somewhat amazed a fully #blind person can even find the power button on a computer, let alone operate it professionally. I am such a person, and I'd like to bust that myth.
It's also true that many #hacking tools, platforms, courses etc. could use some help in the #accessibility department. It's a neverending vicious circle.
Enter my new twitch channel, IC_null. On this channel, I will be streaming #programming and #hacking content including THM, HTB and who knows what else, from the perspective of a #screenReader user.
What I need, is an audience. If this is something you reckon you or anybody you know might be interested in, drop the channel a follow or share this post. Gimme that #infoSec Mastodon sense of comradery and help me out to make this idea an actual thing :) twitch.tv/ic_null #tryHackMe #streamer #selfPromo

robryk boosted

Eh, why does the most recent consequently use value and cost interchangeably~~~

@freemo

Putting "mas.to/@TechConnectify/1123283" in qoto's searchbar results in an error toast saying "500". When I look at network requests involved, I see a request to "qoto.org/api/v2/search?q=https" returning an error page with status code 500.

But also, the volume of the sound I was hearing wasn't that high, so either I failed to notice the same effect when I was hearing louder lowish frequency sounds, or this is more pronounced because eyes are "closer" to teeth than ears.

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I guess I can bust out my bone conduction speaker that I have somewhere and try using that to have a continuous frequency variability (without messing with play-doh).

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Vibrating your head blurs your vision (try taking a metronome or substitute, striking it, and then touching your teeth with the stem while looking at something with a well defined edge or ridge: the picture will become slightly blurry).

I wonder what's the frequency dependence. I have two (nonlocking) forceps that, when measured with my phone's accelerometer, give similar amplitudes of ~50Hz+harmonics and resp. ~60Hz+harmonics. Maybe I'm placeboing myself, but it seems to me that the blur from 50Hz one is significantly larger.

How thick (perpendicularly to the surface) is a stroke of a nonerasable marker? Does it depend on its color? I assume it does depend on the surface -- I would expect it to have no thickness on paper but some thickness on e.g. metal.

Totally random: videos on youtube.com/@Shaddicus give a perspective on powerplant operations that's otherwise hard to get (for me they explained a few things that I found surprising in simulators).

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this past Saturday night, a Dutch train conductor was punched and knocked down the stairs by a rowdy passenger, and so this coming Saturday night, they’re gonna throw the brakes on the entire national train system for a few minutes to give everyone an earful about respect and safety. I’m bringing this up because I feel like no American institution would do that because one of their employees got decked by a customer.

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robryk boosted

looking for work, boosts appreciated 

I’m a software developer with about 6 years of experience. My most recent work was in Rust, but I’m also comfortable with C++ and Go, and happy to work with any language. Most of my experience is with, broadly speaking, backend work. I also have SRE skills, a strong background in mathematics and CS, experience working with distributed systems and cryptography, and experience prioritizing and organizing work within a team.

I would prefer a job that:

Provides a non-negative value to society.
Preferably is remote, but I live in Switzerland and am willing to relocate to English or German speaking countries or Poland if the offer is interesting enough.
Works on something long-term, rather than chasing trends.

Any leads appreciated! #GetFediHired

Disclaimer: quarter-baked

Roughly half of primary school students have some experience with the concept of braids and maybe with the practice of making them. At the same time braids are nice objects to study, because they form a noncommutative group with infinite order elements.

So, would it be possible to pose some interesting-but-approachable problems about braids[1] to primary school kids? Obvious ideas for me are:
- how can we describe a braid?
- do two braid descriptions describe the same braid? what does this even mean? this can naturally introduce a concept of "invariants" (in the sense of a function from a braid representation that is equal for all representations of the same braid) and the concept of transformations of descriptions (and then maybe completeness of that)
- is every braid a commutator of two braids? (sadly this doesn't seem very natural here),
- what generator sets are there? is it sufficient to flip adjacent strands only?

[1] morally similar to "how many isometries does a cube have?"

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