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jaseg, to random
@jaseg@chaos.social avatar

Lol, I decided after not using it for a while I should try FreeCad again. I tried to do a very simple model in it, which needed a thread. Turns out that in 2024 CE, FreeCad somehow still can't do (arbitrary pitch and diameter) threads. How?! I thought this is a CAD tool?! 😬

jaseg, to random
@jaseg@chaos.social avatar

An actual product sold in a German supermarket

jaseg, to linux
@jaseg@chaos.social avatar

So my just catastrophically self-destructed. I was using arch with the yubikey full-disk encryption package, when the machine hung and crashed during a system update. The machine crashed exactly after the old initramfs files were cleaned up, and before the new ones were written to disk. Since the yubkikey fde thing stores the seed ("challenge") for the luks key in the initramfs, all copies of the seed are gone now, and the data on that disk is unrecoverable.

jaseg,
@jaseg@chaos.social avatar

Quite the failure mode if you ask me. I guess I will be scraping that yubikey fde thing from all of my machines now, and go back to plain passphrases. Deleting the old seed files before the new ones have been written and flushed to disk is a pretty bad design error.

jaseg,
@jaseg@chaos.social avatar

Update to the update: The creators of the yubikey full disk encryption thing have responded to my bug report with what is essentially a shrug emoji and the line "I hope you had [a backup]".

I don't think that's an appropriate reponse from the maintainers of a critical piece of software like this. I think if you choose to release software like this, you have a responsibility to either make it good or to at the very least warn users that it's bad.

jaseg, to random
@jaseg@chaos.social avatar

This place has such a different vibe at 3am UTC compared to 3pm UTC

jaseg, to Electronics
@jaseg@chaos.social avatar

I just found an interesting genre of weird but potentially useful chip: System support PMICs for large SoCs such as BD71805 (2$, i.MX SoCs), RK809 (2$, Rockchip SoCs) or WL2868 (50ct, Omnivison SoCs). These chips provide between 7 and around a dozen DC/DC or LDO channels with digitally configurable voltage(!) through I2C, battery charge measurement, and configurable power-on sequencing. Some even have fun bonus features such as an RTC, or a built-in audio codec(?!).

jaseg,
@jaseg@chaos.social avatar

@projectgus If anything, I'd think an SoC like that would have worse load behavior than something I cobble together with much lower operating frequency components. I suspect the biggest difference to a standalone LDO with these would be poorer analog performance, in particular poor output noise and PSRR specs as these aren't that important for SoCs.

jaseg,
@jaseg@chaos.social avatar

@projectgus The WL2868 I mentioned above would be an exception from that though. Since it's meant for camera sensors, it has several LDOs spec'ed with very good PSRR and decent noise specs.

jaseg, to Electronics
@jaseg@chaos.social avatar

RF transistor manufacturer CEL tells you in their datasheets not to lick their transistors.

https://www.cel.com/documents/datasheets/CE3512K2.pdf

akendo,
@akendo@chaos.social avatar

@jaseg You know, when someone has to write it into the documentation, it means that it has history.

jaseg,
@jaseg@chaos.social avatar

@akendo I want to know the story of the presumably very bored PhD student who decided to "chemically make gas or powder with [a CE3512K2 transistor]"

jaseg, to Electronics
@jaseg@chaos.social avatar

ST's latest and greatest idea is to sell the same part in the same BGA package in two subtly different pinout variants. The two variants are only distinguished by the last letter of the part number, which is at the end of the flash size and temperature variant section that does not affect the pinout in any other part they make. The package letter of the part number is identical for both variants.

Link: https://www.st.com/en/microcontrollers-microprocessors/stm32h7r3l8.html

salkinium,
@salkinium@chaos.social avatar

@jaseg Ah yes and the CubeMX database is also confused about the SMPS and non-SMPS package (table from https://salkinium.com/hp23.pdf):

jaseg,
@jaseg@chaos.social avatar

@salkinium Heh, good to know. I should probably read through your paper and make sure these are all fixed in KiCad's libraries.

jaseg, to random
@jaseg@chaos.social avatar

Ooof, please correct me if I'm wrong about this. If I understood it right, the authors of the paper linked below, published at NDSS (a respected academic IT security conference), sell it as an interesting research result that off-the-shelf consumer keyboards are susceptible to electromagnetic interference, and can mis-recognize keystrokes when overloaded with extreme levels of EMI.

https://www.ndss-symposium.org/wp-content/uploads/2024-15-paper.pdf

jaseg, (edited )
@jaseg@chaos.social avatar

They go on stating that they can target particular keys of the keyboard, but AFAICT they were only able to do that for some keys, and then only if they positioned the transmit antenna in a particular spot centimeters above the keyboard. The obvious question is which attacker can place an antenna at a chosen location centimeters away from your keyboard, while not being able to just like, push the keys, or plug in a USB rubber ducky or something.

HeNeArXn,
@HeNeArXn@chaos.social avatar

@jaseg the ghost key thing seems the most maaaybe interesting to me, if it generalizes to e.g. some keypads on embedded stuff.

jaseg, to random
@jaseg@chaos.social avatar

German companies can have surprisingly little self-awareness. Or maybe they're just really not planning to ever sell internationally.

jaseg, to random
@jaseg@chaos.social avatar

How not to do graphs in a scientific paper: The attached picture shows one figure from a paper with eight bar graphs. About two thirds of the bars in this picture have been cut off, and do not have any relationship anymore to the magnitude of the underlying number they are supposed to depict. These graphs are functionally useless for their original purpose, and serve as nothing more than sorted tabular data in a particularly awkward format.

cccpresser,
@cccpresser@chaos.social avatar

@jaseg can you please post a link to the paper?

jaseg,
@jaseg@chaos.social avatar

@cccpresser Sure, here you go: https://dl.acm.org/doi/pdf/10.1145/3470496.3527392
"PPMLAC: High Performance Chipset Architecture for Secure
Multi-Party Computation" by Zhou, Xu, Wang, and Gao, published at ISCA ’22

The figure pictured above is on page 12 (PDF) / 98 (Proceedings).

jaseg, to random
@jaseg@chaos.social avatar

I have made it my mission to file an abuse report for every single academic journal spam email that reaches my inbox this week. Or until I get tired of it at least. So far, I got two from gmail using custom domains, and one from some random yahoo address.

jaseg, to random
@jaseg@chaos.social avatar

Reassuring to see that emails to abuse [at] yahoo.com bounce with an error message that some yahoo MTA can't find the alias they internally forwarded that address to.

jaseg, to 3DPrinting
@jaseg@chaos.social avatar

I repaired my 3D printer today. It's a bed slinger, and it had a broken wire in the wiring loom going from the base to the bed. Overall, a sketchy construction in that they used mechanically fragile silicone wires along with not temperature-resistant PVC wires wrapped in a PVC jacket that's also not temperature resistant. I replaced all of them with Lapp Ölflex Heat 205, a wire that is actually rated for the temperature and mechanical stress it experiences in this application.

mutthew,
@mutthew@mastodon.social avatar

@jaseg who was the "they"?

jaseg,
@jaseg@chaos.social avatar

@mutthew Anycubic, the manufacturer of the printer. But AFAICT the sketchy silicone wire is common to pretty much all cheap 3D printers. It creeps me out a bit, because with the silicone being so soft, all of the bending stress goes right into the copper. In the wire I removed from my printer, there was noticeable work hardening in some spots.

jaseg, to opensource
@jaseg@chaos.social avatar

It looks like microsoft did a microsoft again when they implemented their new fake sudo command. They basically repeated the same mistakes they made when they added that ill-advised fake curl to powershell, and stole the name of an existing utility without implementing any of the semantics, or caring about compatibility. I'm willing to attribute this to incompetence rather than maliciousness.

svenk,

Interestingly there was already https://gerardog.github.io/gsudo/ but MS made their own poor version. In enterprise world, it will get used anyway instead of gsudo (which is suspect because third party). So end of the day, MS Win terminal gets a bit more useful. At least.

jaseg,
@jaseg@chaos.social avatar

@hagarashi8 You could totally do that. Windows has had a "runas" tool since before powershell even, and it hat the same semantics as fake sudo: It would UAC prompt you to elevate privileges. AFAICT the major motivation behind their fake sudo is that previously, it was not possible to get the standard input and output of an elevated subprocess launched through runas connected to the parent terminal. The process would either run completely in the background, or have its own terminal window.

jaseg, to random
@jaseg@chaos.social avatar

TIL that sudo, the unix command line utility, has a logo. And that logo is cursed.

https://commons.m.wikimedia.org/wiki/File:Sudo_logo.png

rrwo,
@rrwo@floss.social avatar

@datenreisender @jaseg

The "Make me a sandwich" used to be a thing that misogynist men would say to women online in the 2000s as a way to harass them.

It's what made the XKCD comic cringeworthy.

18+ jordan,
@jordan@sometimes.social avatar
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