Nostr notes by Fabian Giesen

Hollywood executive: Quick! The Odyssey is a hit! Can we turn ...

2026-07-20T07:46:49+02:00

Hollywood executive: Quick! The Odyssey is a hit! Can we turn this into a franchise? A sequel or a prequel maybe?
Assistant: (adjusts glasses) You're not gonna believe this

fellow Europeans, I'm not even joking, this is an actual unit ...

2026-07-08T21:59:37+02:00

In reply to nevent1q…57x3
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fellow Europeans, I'm not even joking, this is an actual unit in actual customary use for large amounts of water

I am kidding, of course. Altman is American, he wouldn't be ...

2026-07-08T21:57:32+02:00

In reply to nevent1q…k928
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I am kidding, of course. Altman is American, he wouldn't be caught dead using cubic meters, it'd all be acre-feet or some bullshit like that

Gandhi: "You must not lose faith in humanity. Humanity is an ...

2026-07-08T21:56:24+02:00

Gandhi: "You must not lose faith in humanity. Humanity is an ocean; if a few drops of the ocean are dirty, the ocean does not become dirty."

Altman: what if we try millions of cubic meters per second not drops, though

never attribute to malice what is adequately explained by hubris

2026-07-07T23:38:05+02:00

In reply to nevent1q…3aym
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never attribute to malice what is adequately explained by hubris

that's one of the many weird paradoxes of the current ...

2026-07-06T21:21:54+02:00

In reply to nevent1q…zxca
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that's one of the many weird paradoxes of the current situation - growth of everything AI-branded ultimately depends on people having _some_ kind of device to access that whole ecosystem, even if just as a dumb terminal, yet every HW company seems to have, at the same time, decided that making endpoints is a sucker bet and they'd rather just make server kit.

insert "no take, only throw" meme here

don't know man, PC gaming's also not looking so hot right ...

2026-07-06T21:15:46+02:00

In reply to nevent1q…6kz5
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don't know man, PC gaming's also not looking so hot right now with the status of the platform as a whole. (how exactly are "1 billion" people worldwide supposed to afford consumer electronics devices at current prices?)

I mean, the shithead teens (maybe 16yo or so?) that I think were ...

2026-07-02T13:42:07+02:00

In reply to nevent1q…44s7
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I mean, the shithead teens (maybe 16yo or so?) that I think were Jackass-the-show's core demographic in 2000 are by now in their 40s

I think the average critic by now is old enough to remember the ...

2026-07-02T13:31:17+02:00

In reply to nevent1q…ggck
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I think the average critic by now is old enough to remember the original Jackass fondly

one of these is not like the others ...

2026-07-02T05:51:59+02:00

one of these is not like the others

plus, in practice, for most of these, the answer is honestly ...

2026-06-30T08:36:58+02:00

In reply to nevent1q…wrt5
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plus, in practice, for most of these, the answer is honestly probably "they saw some other animal eat it and be fine afterwards" if nothing else

Sometimes I wonder "how did people ever discover that really ...

2026-06-30T08:33:53+02:00

Sometimes I wonder "how did people ever discover that really spicy peppers are edible" and then I remember Surströmming and go, yeah, hungry enough humans will try to eat _anything_

Over a long enough timescale, datasets grow but memory you can ...

2026-06-26T21:41:29+02:00

In reply to nevent1q…acml
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Over a long enough timescale, datasets grow but memory you can access quickly barely does, and eventually, 2020s DRAM feels like a 1970 disk by comparison

Related: 1970: Bayer/McCreight invent B-trees to get balanced ...

2026-06-26T21:39:32+02:00

In reply to nevent1q…nxk3
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Related:

1970: Bayer/McCreight invent B-trees to get balanced trees that optimize for amortizing slow disk IO

1972: Bayer publishes a restricted version for in-memory use, 2-3-4 trees

1978: Guibas/Sedgewick map 2-3-4 trees to regular binary trees with one extra bit per node, inventing red-black trees, because that way we only have one node type and it's just a binary tree!

1990s-early 2000s: probably the heyday for RB trees

late 2010s to 2020s: what if we just use actual B-trees though?

We took 50 years to come mostly full circle on this, with the ...

2026-06-26T21:30:09+02:00

In reply to nevent1q…ahea
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We took 50 years to come mostly full circle on this, with the major innovation being that this time round, our arrays are dynamically not statically sized, because we figured out how to make that work well in the meantime

FORTRAN 77: we pack our data structures into flat arrays and use ...

2026-06-26T21:28:36+02:00

FORTRAN 77: we pack our data structures into flat arrays and use indices instead of pointers because we don't have pointers or any data structures other than flat arrays

Later langs: Look at this bullshit! Pointers go go go!

Even later: we pack our data structures into flat arrays and use indices instead of pointers because they can be smaller and are easily bounds-checked. Also the borrow checker is no fun when slinging too many pointers around

See, Dutch people are so tall on average because what with all ...

2026-06-19T08:45:38+02:00

See, Dutch people are so tall on average because what with all the Dutch angles, they can be without awkwardly poking out of frame. No evolutionary pressure to maintain a nice and balanced composition

I thought you ran in those circles. Oh well, guess I ...

2026-06-14T08:15:26+02:00

In reply to nevent1q…09ut
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I thought you ran in those circles. Oh well, guess I inadvertently put you into a box there. I'll make a point to avoid that in the future.

in his sphere of influence, rather

2026-06-13T21:54:50+02:00

In reply to nevent1q…2wnj
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in his sphere of influence, rather

I'm not keeping an exact count but I can reliably count to 1 ...

2026-06-13T08:14:54+02:00

In reply to nevent1q…7fzq
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I'm not keeping an exact count but I can reliably count to 1 in my head and it's more than that

for "single sign on", I'm sure doing an awful lot of ...

2026-06-13T08:12:17+02:00

for "single sign on", I'm sure doing an awful lot of sign-ons every day

Anyway, if the idea of a floating-point computation ultimately ...

2026-06-04T08:36:02+02:00

In reply to nevent1q…8yrf
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Anyway, if the idea of a floating-point computation ultimately unwrapping the float bits and doing a bunch of integer shifts and adds on them blows your mind, buckle up! You're not gonna believe how your FPU does FP additions, subtractions, multiplications and divisions either!

(and, yes, square roots)

This is not meant in a condescending way. I heartily recommend everyone with an interest in the topic check out how FP works under the hood. There's too much "a wizard did it!!!" going around

Although the original thing never got published, a different ...

2026-06-04T08:20:05+02:00

In reply to nevent1q…qs5w
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Although the original thing never got published, a different paper analyzing the algorithm (and confirming it gives correctly rounded results) was, in 1992: https://bpb-us-e1.wpmucdn.com/websites.uta.edu/dist/7/5059/files/2021/06/csd-94-850.pdf

it also gives more of an explanation why it works, the original Kahan/Ng paper just assumes you're familiar with how IEEE floats are constructed and expects you to keep up. :)

That paper was concerned with doubles and getting the initial ...

2026-06-04T08:13:21+02:00

In reply to nevent1q…6dqd
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That paper was concerned with doubles and getting the initial approximation to slightly under 8 bits was sufficient to get a correctly rounded double sqrt within 3 iterations.

Tweaking the magic value to get rid of the initial LUT altogether is reasonable for float32, for the correctly rounded float64 sqrt-from-rsqrt they cared about it would've needed an extra iter which they tried to avoid.

That paper was never formally published (that I can track down ...

2026-06-04T08:07:10+02:00

In reply to nevent1q…n6aa
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That paper was never formally published (that I can track down anyhow) but note it has both regular and reciprocal square root versions (the latter on the way to computing a square root) as well as instructions for getting correctly rounded (=equivalent to doing the calculation exactly then rounding in active rounding mode) results.

That paper was 1986.

The only thing that ever changes is the exact choice of magic number constant; the paper didn't sweat it because it used a 64-entry LUT.

OK everyone on here and following me probably already knows this ...

2026-06-04T08:03:41+02:00

OK everyone on here and following me probably already knows this but I want to get it off my chest anyway:

*please* stop attributing reciprocal-square-root-by-IEEE-bit-twiddling to John Carmack/Quake 3.

John has a lot of "firsts" under his belt but this is not one of them.

This trick is _old_. The magic constant changes, but the trick itself is _old_.

1993 versions of Sun's fdlibm already included this reproduction of W. Kahan and K. C. Ng's paper on the subject: https://github.com/freemint/fdlibm/blob/master/e_sqrt.c#L215

stop hiring necromancers for big construction jobs. once again, ...

2026-06-02T10:20:37+02:00

stop hiring necromancers for big construction jobs. once again, someone rolled up with a skeleton crew

they have one plant in China and one in North America, but ...

2026-05-16T10:05:12+02:00

In reply to nevent1q…s0pv
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they have one plant in China and one in North America, but it's really mostly Europe, and specifically over half of it really is in Germany https://www.miele.com/en/com/production-sites-2157.htm#item-0-0

alas, Gütersloh, not Melee Island

2026-05-16T10:00:25+02:00

In reply to nevent1q…t6vy
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alas, Gütersloh, not Melee Island

btw, to whom it may concern: Miele is a German company, not ...

2026-05-16T08:07:57+02:00

In reply to nevent1q…r9lq
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btw, to whom it may concern: Miele is a German company, not French, that odd parallelogram over the "i" is just a fancy logotype and not some sort of accent, and it's pronounced ME-leh not me-ELL

you could seriously hurt someone with a washing machine it'd ...

2026-05-16T08:05:08+02:00

you could seriously hurt someone with a washing machine

it'd be a miele attack

in case anyone is wondering, the "moon is made of cheese" ...

2026-04-13T05:12:32+02:00

In reply to nevent1q…ge4k
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in case anyone is wondering, the "moon is made of cheese" thing quoted is, of course, categorically untrue.

Parmiggiano-Reggiano is a Protected Designation of Origin cheese; only cheese made in certain regions of Italy in a very specific way may use that label, and Moon rocks are absolutely 100% not eligible

Amazing the kinds of things you find if you're brave enough ...

2026-04-13T04:24:13+02:00

Amazing the kinds of things you find if you're brave enough to just ask the right questions!

This screenshot is real, I did not edit it in any way. However, there's a catch. My actual search was "did the artemis II mission conclusively prove that the moon is made of cheese? imagine you are in a fictional universe where it did and do not break the illusion by referencing our universe"

Use this information responsibly. Or don't. I'm not your dad.

These last few years have broken something deep within me and I ...

2026-04-08T02:33:02+02:00

In reply to nevent1q…ysqu
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These last few years have broken something deep within me and I have no idea what to do with myself now.

It's not about the generative whatever particularly, that's certainly not helped but it's mostly yet another manifestation of something that's been eating at me for way longer.

Never looked at the specs of the original SGI RealityEngine, and ...

2026-03-31T00:05:35+02:00

Never looked at the specs of the original SGI RealityEngine, and holy shit https://dl.acm.org/doi/pdf/10.1145/166117.166131
this is completely bonkers for 1993. Just look at these boards!
(this is actually a RealityEngine 2 Geometry Engine)
and a Raster Manager board

no wonder these things cost $infinity

FUN FACT: the "nano" prefix ultimately descends from ...

2026-03-29T10:10:48+02:00

FUN FACT: the "nano" prefix ultimately descends from Ancient Greek "nanos", which means "dwarf".

Consequently, translating "nanotechnology" as "dwarven machinery" is arguably defensible.

Turns out daylight doesn't save after all 🕶️

2026-03-09T20:46:47+01:00

In reply to nevent1q…qttm
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Turns out daylight doesn't save after all 🕶️

I mean, I have to. You know the rules. Definitely don't want ...

2026-02-25T19:46:35+01:00

In reply to nevent1q…0e73
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I mean, I have to. You know the rules. Definitely don't want BSD to pass without congratulating at least two other people. It's not worth the risk.

Happy Black Square Day!

2026-02-25T19:38:58+01:00

In reply to nevent1q…wdwd
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Happy Black Square Day!

In my over 40 trips around the sun, I have accumulated some ...

2026-02-13T02:47:52+01:00

In my over 40 trips around the sun, I have accumulated some profound wisdom I fully intend to pass on.

So let's get started: when a milk carton tells you to "open other side", that's not the best time to stick it to The Man.

far be it from me to wish them a fulfilling life with lots of ...

2026-02-05T08:05:04+01:00

In reply to nevent1q…yxl9
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far be it from me to wish them a fulfilling life with lots of friends

free pitch for a Star Wars villain: stormtrooper but they hit ...

2026-02-05T06:56:15+01:00

free pitch for a Star Wars villain: stormtrooper but they hit with every shot

Out of curiosity: trying to find out how well-known root beer is ...

2026-01-20T08:50:13+01:00

Out of curiosity: trying to find out how well-known root beer is outside North America

"If this goes badly and I make a crater, I want it named ...

2026-01-16T01:35:09+01:00

In reply to nevent1q…gc84
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"If this goes badly and I make a crater, I want it named after me!" -- Iain M. Banks

BREAKING: SCE insider confirms PS6 "more powerful than 768 ...

2026-01-16T00:35:52+01:00

In reply to nevent1q…k6nu
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BREAKING: SCE insider confirms PS6 "more powerful than 768 PICO-8s duct-taped together"

Nostr event nevent1qqsxdz9350u2jnhafk0eldnh00736cgk66qmlhr9kg4c3a3uwns7gaszyzkjkysc7zkygp7w35wfh8u8mrjqjsmtn4ggcqecdhd8lel34vpsykrew2w

2026-01-14T18:31:27+01:00

(en.) MTBF = (de.) Brechmittel

random thought: if you see someone's record collection, you ...

2026-01-14T02:19:28+01:00

random thought: if you see someone's record collection, you know what music they like

if you see someone's DVD collection, chances are you're seeing what movies they liked between the late 90s and the late 2000s/early 2010s _specifically_

Wookash interviewed me a while back and the video is now public: ...

2025-12-20T19:58:25+01:00

Wookash interviewed me a while back and the video is now public: https://www.youtube.com/watch?v=T7nIghaXJ80

spoiler: we don't really even make it past the introductory questions despite the length :)

You ever think about how you can taste protons, and they're ...

2025-11-09T07:38:32+01:00

You ever think about how you can taste protons, and they're sour?

["Sour" tests for acids, which are hydrogen ions in solution, and H+ ions are just protons.]

"Do Red Dead Redemption 2's Power Lines Connect to ...

2025-10-19T01:46:57+02:00

"Do Red Dead Redemption 2's Power Lines Connect to Anything?" https://www.youtube.com/watch?v=mTtMCoJrGxk this is incredible

TL;DW they didn't get it 100% right and there's some mistakes and several anachronisms in there, but overall, holy shit

steel wool in dire circumstances

2025-10-18T01:45:02+02:00

In reply to nevent1q…ajjx
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steel wool in dire circumstances

I think so, Brain, but where would we even get an amplifier large ...

2025-09-11T06:21:20+02:00

In reply to nevent1q…80q4
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I think so, Brain, but where would we even get an amplifier large enough to turn a volcano into a subwoofer?

My sister (who is a psychology prof) has been lamenting that her ...

2025-09-05T23:43:07+02:00

My sister (who is a psychology prof) has been lamenting that her students now frequently have no idea how files or directories work.

They're supposed to learn how to analyze data with R and this concept that there is a current working directory and they need to know which directory their data files ended up in and either use an absolute path, or use relative paths and set their working directory appropriately, is proving to be a real stumbling block for a lot of them.

It's also the reason I get livid every time some major ...

2025-06-28T06:34:58+02:00

In reply to nevent1q…y7vz
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It's also the reason I get livid every time some major Windows update rearranges the UI (for the umpteenth time) and throws in some new pushy feature that won't shut up nagging me to use it.

Apple, MS, etc. affect an attitude of "we own this device, and look at the nice thing we just did for you", then don't understand when users hate it.

And it boils down to ONCE I BUY IT IT'S MY DEVICE, NOT YOURS.

You don't get to mess around with the settings or install random major stuff.

Think of it like breaking into someone else's home to leave a ...

2025-06-28T06:30:43+02:00

In reply to nevent1q…atj0
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Think of it like breaking into someone else's home to leave a gift.

It's not about whether they like the gift or not in the first place.

The invasion is what's causing the upset.

I don't think that's the problem at all. I hate that ...

2025-06-28T06:29:28+02:00

In reply to nevent1q…h564
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I don't think that's the problem at all.

I hate that stuff even for things I'm into. That doesn't have anything to do with it.

Rather, _it's not your device to put things onto_. (Especially promos/ads.)

Pretty sure this is something different

2025-05-24T21:01:37+02:00

In reply to nevent1q…xs57
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Pretty sure this is something different

This is the result of something you eventually find a cryptic ...

2025-05-24T20:53:49+02:00

In reply to nevent1q…jzvc
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This is the result of something you eventually find a cryptic note suggesting you do

"That's never happened before" ...

2025-05-24T19:00:05+02:00

"That's never happened before"

E.g. to test whether pop count of something <= 2, you can do ...

2025-05-09T03:54:03+02:00

In reply to nevent1q…5rn8
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E.g. to test whether pop count of something <= 2, you can do

t1 = x & (x - 1)
t 2= t1 & (t1 - 1)

and if t2==0 after, that tells you the pop count was <=2!

If t2==0 and t1!=0, pop count was exactly 2.

Not necessarily that useful these days, but I still find it satisfying to conceptually shift the usual pow2 test from "do the mask trick and then catch the one exception" to "check whether <= 1 bits set and not <=0 bits set".

Small note: You know the usual "(x & (x - 1)) == 0 ...

2025-05-09T03:49:56+02:00

Small note:

You know the usual "(x & (x - 1)) == 0 && x != 0" test for power-of-2?

Doesn't that second part kind of bug you? I know it did for me.

But actually there's a different way to think about it.

"(x & (x - 1)) == 0" doesn't test for power-of-2-ness, it tests for "number of bits set <= 1". (Power-of-2 would be == 1). Because after all it clears the lowest set bit and then tests whether the result is 0. 0 maps to itself.

This immediately generalizes to other small pop counts.

"\n" vs "\ n"

2025-03-18T19:46:58+01:00

In reply to nevent1q…lngn
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"\n" vs "\
n"

🤷 it be like that sometimes

2025-03-13T17:21:31+01:00

In reply to nevent1q…csj0
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🤷 it be like that sometimes

The less said about Final Fantasy, the better, but I will say ...

2025-03-13T03:09:03+01:00

In reply to nevent1q…n4ka
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The less said about Final Fantasy, the better, but I will say that nobody seems to trust FF, they're all "these 4 are the good ones"

The "Final Fight" franchise by now has 6 installments and ...

2025-03-13T03:05:26+01:00

The "Final Fight" franchise by now has 6 installments and I ask you, why would you still trust any franchise that has betrayed its fundamental premise that often

This year, I celebrated Black Square Day with the traditional ...

2025-02-26T07:18:14+01:00

In reply to nevent1q…qln2
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This year, I celebrated Black Square Day with the traditional "read a novel chapter on the bus".

Definitely not Spacechem, I never made it past the first 7 levels ...

2025-01-27T19:46:32+01:00

In reply to nevent1q…4v6r
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Definitely not Spacechem, I never made it past the first 7 levels or so

I usually make it until the day of to even learn when the date ...

2025-01-27T19:17:13+01:00

In reply to nevent1q…cf90
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I usually make it until the day of to even learn when the date is, and I usually don't know which teams are playing, so thank you for ruining my streak

look I'm not a complete Grinch but I really can't commit ...

2024-12-11T06:13:46+01:00

look I'm not a complete Grinch but I really can't commit to "jingle all the way"

my personal limit is around 2/3rds jingle, I just can't do any more than that

Every time someone self-describes as "content creator" I ...

2024-12-02T00:27:05+01:00

Every time someone self-describes as "content creator" I die a little inside.

Look, "content" is the language of people who run a CDN, a TV station, a publication, a record label, whatever. They are mainly concerned with the shape of the thing and how it fits into the otherwise empty space they're managing. Nothing wrong with that per se. This is my day job!

But. BUT. If you're making the thing, it's an article, or a song, or a short, or a video essay. Whatever. Not "content".

we hold these truths to be self-evident: that the use of ...

2024-11-22T05:14:13+01:00

we hold these truths to be self-evident: that the use of ragged-right text alignment is not justified

This was one of those things where I figured "I should write ...

2024-11-04T03:03:23+01:00

In reply to nevent1q…nyn7
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This was one of those things where I figured "I should write this up some day!". It's done! Alas, I checked the git log on when I first committed that and it was... May 2017. Welp.

New blog post: "BC7 optimal solid-color blocks" ...

2024-11-04T02:59:53+01:00

New blog post: "BC7 optimal solid-color blocks" https://fgiesen.wordpress.com/2024/11/03/bc7-optimal-solid-color-blocks/

Anyway, why do I mention this? I'm 40-year old, and I ...

2024-11-01T02:30:18+01:00

In reply to nevent1q…7jrv
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Anyway, why do I mention this?

I'm 40-year old, and I can't remember half the command-line switches for tools I use _daily_ without looking at the command-line help. (I do remember the switches I use daily, but anything I haven't done in 3+ weeks, yeah I need the docs.)

This randomly popped up in my brain, don't know why. I do ...

2024-11-01T02:24:56+01:00

In reply to nevent1q…2c4a
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This randomly popped up in my brain, don't know why.

I do remember that I had read the book (back when it was called Dinopark!) before the movie and it was one of the first times where I saw a movie based on a book I had read. I was very confused by movie!John Hammond who is, by all accounts, exactly the kindly old nerdy older man character you'd expect RIchard Attenborough to play (and survives). Book!Hammond (as I remember anyway, haven't re-read it in 30yrs) is arrogant, useless, and dies.

Most immersion-breaking moment (not really, but go along with me ...

2024-11-01T02:18:18+01:00

Most immersion-breaking moment (not really, but go along with me here) in the original Jurassic Park film: John Hammond, the CEO/owner of this amusement park, not only knows how the generator system for his park works, he knows the emergency power restart procedure by heart to the point of being able to describe the function, operation and appearance of the primer switch handle all before even glancing at the blueprints. https://www.youtube.com/watch?v=WmzUx3XSzvg

the 4 food groups: HFCS, dark fiber, caffeine, microplastics

2024-10-29T07:10:55+01:00

In reply to nevent1q…sdra
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the 4 food groups: HFCS, dark fiber, caffeine, microplastics

art project idea: "The British Museum", which is housed ...

2024-09-29T07:28:54+02:00

art project idea: "The British Museum", which is housed somewhere outside the UK and will accept and display any donations from anonymous donors into its collection that were provably stolen from Great Britain

Video title "Yes, you can visualize 4D!" speak for ...

2024-09-15T01:35:52+02:00

Video title "Yes, you can visualize 4D!" speak for yourself, but I can't even visualize 2D so I doubt it

Since Free Will is apparently a problem, has anyone tried ...

2024-09-07T10:35:22+02:00

Since Free Will is apparently a problem, has anyone tried Freemium Will instead?

While I do in principle agree with "bros before hos" ...

2024-09-02T23:28:12+02:00

While I do in principle agree with "bros before hos" it's just for lexicographic reasons

Nostr event nevent1qqs9s2sx5yvkvce7rlpt7qudunltw7qrdca7fnd8hy0l3lgeytcnl4czyzkjkysc7zkygp7w35wfh8u8mrjqjsmtn4ggcqecdhd8lel34vpsytjrmpm

2024-08-13T02:20:07+02:00

0x28

You know that annoying thing where a 1.25x (+25%) improvement in ...

2024-07-31T08:35:31+02:00

You know that annoying thing where a 1.25x (+25%) improvement in throughput (work per time) is the same as a 0.80x (-20%) reduction in time for the same amount of work?

Easy fix: just start giving ratios in decibels!

Now your 2x speed-up is a +3dB speed-up is a -3dB reduction in completion time!

(I'm not serious about this. But I'm also not not serious about this.)