<gorgonical>
Actually incredible that this information is just on the internet
<zid`>
6 month old plane, line number is 8907
<zid`>
produced in Renton
<gorgonical>
It's very new feeling. So new that it doesn't have functioning tablets. The tablets are in the seats but they don't work lol
<zid`>
delivered 10th of may, entered service 8th of june
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<zid`>
gorgonical: if you were going over the right bit of airspace, I'd be able to listen to your pilot talking to atc, which is kinda nutty
<gorgonical>
you'd hear him complaining about turbulence
<gorgonical>
though I have heard pilots secretly really like turbulence because it isn't as boring
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<kof673>
pdp-frog: "32V, 3BSD and 4.0BSD on a VAX-11/780" those apparently run on simh too, have not tried yet :D
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<geist>
hmm, might be interesting to play with 32V
<zid`>
like, licking it?
<zid`>
I've licked 50V, do not recommend
<gorgonical>
I don't know enough about electrophysics to recommend
<gorgonical>
I watch that electroboom guy and I think half the time I guess wrong about what will happen
<zid`>
well it tastes very like electricity
<zid`>
and sort of like metal
<gorgonical>
A recent video explains that having a high voltage doesn't always mean you can get a shock because the system can't deliver enough energy to keep the voltage high
<zid`>
yea that's why you can touch plasma balls and stuff
<zid`>
they're high voltage but can't drive any current for shit
<gorgonical>
that's the part I don't really get. What's not driving? I understood voltage to be the electric pressure equivalent
<zid`>
There's 10kV between the positive and negative, but it can only fire like 4 electrons that fast
<gorgonical>
electricity confusing
<zid`>
'power' is what you care about, here
<gorgonical>
I guess it can be understood as similar to how space is hot
<zid`>
yea space is infact, hot
<gorgonical>
but when only one particle bumps into you it doesn't matter as much how hot it is
<zid`>
yea that's why you care about 'power'
<zid`>
which is V * I
<zid`>
so high voltage *could* cause a lot of power to flow, but only if enough I (amperage) is actually happening
<gorgonical>
Oh that makes sense. At least DC is simpler. I have EE friends and they have tried to explain the equivalents in AC
<zid`>
In most situations, these voltages are coming off power supplies, and the voltage just shrinks in proportion
<zid`>
and you end up with a constant *wattage*
<zid`>
for say, a 5V phone charger
<zid`>
If there's an amp flowing, it's 5W of power, but if the charger is only rated for 10W, if you tried to draw 10A, it wouldn't work and the voltage would just collapse and you'd end up with 10A at 1V instead, still the same 10W
<gorgonical>
oooh
<zid`>
10A at 1V being like, a bus packed with really slow moving electrons, 1A at 10V being a few electrons in a fast car
<gorgonical>
This is basically required by the downstream v=i*r equation too right?
<zid`>
yup
<zid`>
The only way to 'draw' more power, is to lower your own internal resistance
<zid`>
Which is why you can touch all these chargers with your grubby little fingers fine
<zid`>
you have 10kOhm resistance per cm of skin or whatever, so the maximum current you could ever get from 5V would be 5/10kths of an amp
<zid`>
or alternatively, you'd need 10kV to get an amp
<zid`>
AC is different because it *can* wiggle you back and forth, like sloshing water in a pool, rather than trying to make a whole pool's worth of water flow through a pipe
<zid`>
based on your inductance instead of your resistance
<gorgonical>
I am consciously restraining myself from recursing into how the power supply limits itself to 10W
<zid`>
Everything's easier as soon as you look at it as power, eh?
<zid`>
10W just completely limits what the V, I and R can be at any point and you're done thinking, hoorah.
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<zid`>
gorgonical: If you wanna know why something like a battery doesn't provide basically infinite power if you short it, it's because they have an 'equivalent series resistance', aka they are also a resistor
<zid`>
So our 5V battery might have 1 Ohm of internl resistance, so if I connected it to a 0Ohm loop of wire, I still only get 5A
<zid`>
which is 25W, not infinite
<zid`>
0.1 ohm is right for an AA battery apparently
<zid`>
and a lead acid car battery is like, 3mOhm, so you can grab hundreds of amps out of them
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<gorgonical>
Which means that unless you do something fancier, a mains power supply that rectifies 240VAC to 5V must generate heat
<zid`>
240V rectifies to 350V DC, to turn that into 5V you *could* use a linear regulator, but you'd be losing 345V * amperage as heat
<gorgonical>
I guess my question is *what* limits the power supply to 10W? If I short the load and pretend I have 0Ohm resistance, I should be able to draw as much power as the supply cna provide
<zid`>
so you do something tricksy
<zid`>
You.. use a timer that only connects the full 350V to a big capacitor and inductor setup for 1ms, then disconnects it for 99ms
<gorgonical>
Yeah the switched supplies
<zid`>
ta-da, switched mode power supply
<gorgonical>
So I mean naturally if you short a 5V power supply unless it has detection circuits, you can totally explode a supply like that
<zid`>
not if its internal resistance is high
<Mutabah>
Yup.
<zid`>
but yes if it's low
<Mutabah>
Well, a high internal resistance means lost efficiency
<zid`>
a car battery will quite happily boil all the sulphuric acid inside of itself and spit it at you if you short it long enough
<gorgonical>
Okay so how do you avoid the internal resistance when you aren't shorting? That's what I don't understand I think
<gorgonical>
Yes, what Mutabah is suggesting. So you either must lose energy as heat or you can explode the supply?
<zid`>
or it drains the caps
<zid`>
and the voltage disappears
<Mutabah>
Decent switchmode supplies will detect over-current, and drop the voltage (to zero maybe)
<zid`>
the output is only fed 1% of the time from its input, and is stored and shorted in fields
<zid`>
which collapse and run out of juice
<gorgonical>
Right we're quickly leaving fundamentals and entering engineering though
<Mutabah>
Oh yeah... good point zid` - It'd just drain the smoothing caps and lead to voltage sag that way
<Mutabah>
Of course, that assumes that the switching circuit doesn't have feedback
<Mutabah>
if it does, then it would just ramp up the duty cycle to maintain voltage
<zid`>
if you drain the caps slightly faster than realtime, they never charge up fully in time, your voltage dips, and that automatically lowers your current, and you stop draining them too fast
<zid`>
and it steadystates at.. 10W
<zid`>
near instantaneously
<gorgonical>
But only for a switched supply
<zid`>
You're not getting more than 10W out of it unless you short it, and that lasts for like, 0.1ms and then it disappears, not long enough for anything to get too hot and let the smoke out
<zid`>
NES consoles like to let the smoke out because they have a linear regulator dropping a voltage from 12V to 5V inside (afaik those are the voltages)
<zid`>
just tossing away 7V * amperage as heat inside the chip
<zid`>
which slowly cooks it
<gorgonical>
a linear regulator being just like a voltage divider resistor
<zid`>
I think they're slightly cleverer than that, else you'd not really be able to pull any current
<zid`>
voltage dividers have the problem that.. if you put a resistor in your circuit you've now destroyed your current
<zid`>
they're great for making reference voltages, bad for power
<gorgonical>
so then it's a series resistor, and you are literally just dumping the excess energy as heat to achieve the desired voltage on the output?
<zid`>
yea, I think it uses a little feedback loop to adjust its own resistance, to turn the *load* into the other resistor, in practice?
<Mutabah>
Linear regulators tend to be zenier diodes (or an amplifier driven by one) - which have a very well defined voltage drop
<zid`>
making it act like a series resistor
<zid`>
or they're zeners yea
<zid`>
which just poofs a bunch of voltage by a set amount
<gorgonical>
Right then back into engineering building blocks
<zid`>
You're dangerously close to quantum mechanics when you start asking how the silicon works :P
<gorgonical>
I daren't
<Mutabah>
Fun fact about zeniers - you install them backwards to get the well-defined voltage
<gorgonical>
When I was beginning my risc-v core design I read a few digital design books that spent a comedically large amount of time on gate design for me
<gorgonical>
Mutabah: that's black magic
<zid`>
(it turns out, that if you put enough of the right atoms close enough, the individual electron orbitals start smushing together into one massive 'band' of orbitals, so your circuits stop acting like electron lasers and start conducting electricity instead blah blah)
<Mutabah>
Yup, serious black magic
<gorgonical>
actual quantum computing is easier because the math is just imaginary linear algebra
<zid`>
(but you can still have two or more bands of orbitals the electrons will go down, and jumping between those bands is what an LED does!)
<gorgonical>
math is easy, physics is not
<zid`>
LEDs are fucking black magic btw
<zid`>
They're zener diodes that give off the loss as photons
<gorgonical>
I did watch the veritasium video about the blue LED
<zid`>
so you have to give them resistors else they just explode
<gorgonical>
agreed, nonsense black magic
<zid`>
Like, you connect 3V to an LED, and it just goes bang
<zid`>
because it decided the amount of current that should flow through it is "yes"
<zid`>
You need 3V but *current limited to 30mA somehow (resistor)* which seems like it should be the same thing but totally isn't
<zid`>
oh yea, I remember the blue led video, that was neat, all the funding issues etc
<gorgonical>
a zener is like a one-way check valve in a pipe
<zid`>
all diodes are, zeners are fucky
<zid`>
in that they actually work in *both* directions
<gorgonical>
no because a one-way check valve will fail with enough pressure
<zid`>
but you need to push harder in one direction than the other
<gorgonical>
so in a regulator the zener diode installed backwards provides an "overpressure" valve because extra voltage will go through it
<zid`>
It's more that it "drops" the voltage
<zid`>
in terms of how people think about it
<gorgonical>
but there's still a resistance so when it breaks down you aren't creating a short
<gorgonical>
?
<zid`>
a short is what you want, for the *remaining* voltage
<zid`>
meaning, it isn't wasting power
<gorgonical>
right. so you install the zener in series with the load
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<gorgonical>
no i mean parallel I think
<zid`>
yea, all the 'over' voltage will get sunk
<zid`>
if you pralrlarlalel it
<zid`>
and appear as being shorted to ground
<zid`>
leaving you with the 5V that didn't get shorted
<gorgonical>
transistors, bro. spooky
<zid`>
resistors are pretty spooky too
<zid`>
If you put them in parallel, the overall reistance is lower
<zid`>
than any of the individuals
<zid`>
My crappy mental model of that was that the area under the graph of x=y, the triangle it draws, has less area if you draw two triangles that are half the length
<zid`>
than a bigger one
<Mutabah>
Same amount of flow, just two equal paths = less lost energy
<bslsk05>
insidehpc.com: Silicon Photonics and the Hunt for an HPC Bandwidth Bottleneck Breakthrough - High-Performance Computing News Analysis | insideHPC
<zid`>
I wouldn't listen to a word the photonics people say
<zid`>
'hpc bandwidth bottleneck' *maybe*
<zid`>
but we already use optical backplanes in datacenters
<gorgonical>
of course they try to convince us photonics is the future
<zid`>
that's just shrinking it into a slightly smaller space
<zid`>
so now it's the pci-e link instead
<gorgonical>
yes but that's the architectural future. heterogeneous and disaggregated
<zid`>
you're not going to *compute* on photonics
<gorgonical>
no of course not
<gorgonical>
I never thought that at least
<zid`>
sounds like you sorta did?
<zid`>
and it's b een a thing forever, people claiming it
<gorgonical>
I didn't mean to suggest it that way, no
<gorgonical>
But the embedded optical links in silicon as a common bus is really interesting. Yeah we've had optical links for a long time
<zid`>
someone made a carbon gate recently btw, sadly it didn't have the speed of light they were expecting, but they had issues even doing it at all, so it's probably super shitty internally
<zid`>
It should be like 10x silicon, which would let you make the substrate 10x thicker and then reduce leakage currents a shit load
<zid`>
so now you don't have the horrendous power density issues
<zid`>
carbon doesn't have a band gap so it isn't a semi-conductor, so you have to do silicon straining tricks again (sigh)
<zid`>
to make it have one
<zid`>
so they basically CVDd it onto something with a larger crystal, I think maybe it was silicon carbide?
<zid`>
and hope it sticks and forms crystals in a strained state
<gorgonical>
my plane is landing now so I will lose connectivity soon. Gotta run
<zid`>
gg, hope I kept you amused
<gorgonical>
it was great fun
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<bslsk05>
<icculus> SDL3 has hit ABI lock!  You can now trust the interfaces to stay stable. We will _add_ but not _remove_ or _change_ what's there, so it's safe to migrate your game to it!  https://github.com/libsdl-org/SDL/releases/tag/preview-3.1.3  We're rushing to an official release from here, but what's there has been battle-hardened in Steam and DOTA2 and CS2 for over a year now, across several platforms.
<heat>
isn't SDL3 like 10 years old at this point
<heat>
hmm no, i was thinking of sdl2
<zid`>
I checked the docs and immediately got annoyed btw
<zid`>
the person who last futzed with them was a C++ weenie and ruined all the spacing
<zid`>
it was like SDL_Surface* SDL_Get_Surface(void *);