Posts by danderson@hachyderm.io
(DIR) Post #AkQGNFFj6znk5oJdUu by danderson@hachyderm.io
2024-07-29T02:38:45Z
1 likes, 0 repeats
To be clear none of this is groundbreaking math or anything, the paper associated with this library was published in 1993, and it appears to be a run-through of code that existed for at least a decade prior. Unit conversion and dimensional analysis are very solved things.... and yet software today still gets it wrong enough to have flamewars, or to go "I'm sorry, attoparsecs per microfortnight into inches per second is just complex enough that I won't bother, please ask simpler questions."
(DIR) Post #AkQGNIwNOshRWxIEtM by danderson@hachyderm.io
2024-07-29T02:41:38Z
1 likes, 0 repeats
I dunno, it's hard to explain, but reading code like this feels good. It won't win beauty awards, someone writing modern Common Lisp probably wouldn't do it this way... But does it matter? Thirty years ago, it comprehensively solved the problem it set out to solve, and still works the same today.It's a warm fuzzy feeling to encounter software that is Done, and doesn't immediately bitrot because the entire universe around it gets rewritten from scratch every two years.
(DIR) Post #AkQGNMB1MtCFZFATdQ by danderson@hachyderm.io
2024-07-29T02:52:50Z
1 likes, 0 repeats
Anyway, https://www.cs.utexas.edu/~novak/units.html is neat. It even has a companion paper that goes through its design, and how it handles some stuff like dimensional analysis and unit simplification that biases towards a chosen system of units. It's neat.If you were redoing it today, I think possibly the things you'd change would be maybe compute all the scaling factors as rational fractions when possible (it's become cheap to do), and maybe change the dimensional analysis encoding slightly? But also, eeeh.
(DIR) Post #AkTSBhhFJXoLl7KYoi by danderson@hachyderm.io
2024-07-11T06:21:16Z
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Speaking of language, sometimes I remember how incredibly weird it is that a software feature designed to help you achieve something is canonically called a "wizard".Oh I need help configuring this, lemme light the beacon and call for the aid of Digital Gandalf
(DIR) Post #AkTSBj8ZxPGkEB7u3k by danderson@hachyderm.io
2024-07-11T06:22:34Z
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Also implies that the default state of software is, I dunno, an orc or a barbarian or something. Something that you need a wizard to help you with, certainly.
(DIR) Post #AkTSBk7CK1l5GBUJXs by danderson@hachyderm.io
2024-07-11T06:33:52Z
3 likes, 5 repeats
Now thinking about creating a movement to promote "hobbit software". Pretty chill, keeps to itself, tends to its databases, hangs out with other hobbit software at the pub, broadly unbothered by the scheming of the wizards and the orcs, oblivious to the rise and fall of software empires around them.Oh, the Electron empire is going to war with the Reacts? Sounds ghastly, sorry to hear that. Me and the lads are off to the pub to run some cronjobs, wanna come along?
(DIR) Post #AkWjOKES9AdxReLZNg by danderson@hachyderm.io
2024-08-01T02:08:09Z
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Skimming some bluetooth specs, I genuinely wonder now: if you transmit, say, 1kiB over the Mesh BLOB profile, how much total airtime and transmitted symbols does that expand to? With the amount of layering involved, I wouldn't be surprised if it's multiple megabits once you're closer to the antennas.
(DIR) Post #AkWjOL4D2k2m2AYu3M by danderson@hachyderm.io
2024-08-01T02:10:44Z
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BLE is like a microcosm of microservice architecture and OSI layering. Every layer has a purpose, but every new thing runs over all the existing layers. So as you climb up the stack you go from 3MB/s on a PtP air link, to 1MB/s, to 125kB/s, to "we conspicuously don't discuss the throughput at this layer, but you get 29 bytes of payload per message."And then they build FTP on top of that.
(DIR) Post #AkWjOLnaK2L8Itn8mO by danderson@hachyderm.io
2024-08-01T02:12:41Z
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From the perspective of being able to ship product quickly, it's undeniably cool. Grab a single chip solution, the associated SDK, and from peloton bikes to insulin pumps to stage lighting controls, there's an API for that.But it does make me wonder what the overhead is on "turn on light number 27".
(DIR) Post #AkWjOMO68HXy88sIgy by danderson@hachyderm.io
2024-08-01T02:22:52Z
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Huh, well, according to at least one article on bluetooth dot com: less overhead than I thought. For 29 bytes of user payload, the claim is that 47 bytes get sent to the RF layer for transmission.So, 40% overhead or so. Not great, not terrible.Although that's only counting the initial transmission. This is Bluetooth Mesh, which uses broadcast flooding in lieu of routing. So, those 47 bytes may get retransmitted a significant number of times as it bounces around the mesh.
(DIR) Post #AkWjOMwU4R3JqmxlI0 by danderson@hachyderm.io
2024-08-01T02:24:09Z
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Though in practice, I suspect there aren't many meshes out there taking full advantage of "up to 32k nodes" and configuring all of them as relays.
(DIR) Post #AkWjONihBBcKGJWGR6 by danderson@hachyderm.io
2024-08-01T02:32:19Z
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Anyway, 400 microseconds and 40% overhead per 29-byte message, but that message comes with authenticated encryption, relaying including store-and-forward, and working multicast. That's honestly kinda neat.Pay no attention to the massive firmware blob in the baseband chipset, and pay no mind to how robustly it might have been implemented.
(DIR) Post #AkdqweKzxcqrQtRTKS by danderson@hachyderm.io
2024-08-03T22:19:19Z
0 likes, 0 repeats
I found it, the true source. 1992 programmer's reference for VGA and XGA on IBM PS/2.VGA is 0 to 0.7V, regardless of what messy reality did
(DIR) Post #AkjirYWCXHiHFfVAn2 by danderson@hachyderm.io
2024-08-07T21:37:31Z
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@foone more importantly, when you find it can you please share the schematics and where to source parts. I uh, "need" one is the wrong word, but you know.
(DIR) Post #AkpsP8tsM42SBEQQC0 by danderson@hachyderm.io
2024-08-10T03:56:13Z
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"Wow only $291.000 for a 20GHz RF generator??""... oh. $291,000. Yeah that's more like it."(in case numeric separators work differently in your locale: two hundred ninety one dollars vs. two hundred ninety one _thousand_ dollars)
(DIR) Post #AkpsPCLzVzJKtIbPvs by danderson@hachyderm.io
2024-08-10T03:57:45Z
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"I would like your best waveform generator!""That will be three hundred grand before tax and accessories.""... Okay, I would like your two hundred dollar-est waveform generator!"
(DIR) Post #Al1KI94MGLCG8IL5lI by danderson@hachyderm.io
2024-08-16T07:44:17Z
3 likes, 4 repeats
"Electronics isn't magic""Also, here is the protective sigil to cast when working with DRAM"
(DIR) Post #AlmUwxqJ2SZx9qzAtE by danderson@hachyderm.io
2024-09-08T03:37:45Z
1 likes, 0 repeats
"Well how much can there possibly be in TeXLive anyway"TeXLive: well, if you want all the things, the ISO's 6GiBGood grief.
(DIR) Post #AlmUx0tbge0AcxYLx2 by danderson@hachyderm.io
2024-09-08T03:40:45Z
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The plus side of this software ecosystem that only ever grows, is I threw it at a random .tex file of unknown age, without looking at the details at all, and out came a perfect pdf.
(DIR) Post #AlrrdA0LNfRzp10Ro8 by danderson@hachyderm.io
2024-09-10T17:44:59Z
0 likes, 1 repeats
ugh I want to keep writing silly FPGA programs but I have to look at the bad screen and do cloud shit instead. You can't even see any flops flip from up here, it sucks.