It's somewhat strange to me that their tech journey is so narrative and ends up with a VM stack, rather than any kind of salvaged / repurposed hard tech. But then again, I'm probably on the forth side of the spectrum.
It's a good first step in that direction, the first attempt at permacomputing good enough to criticize.
Many of these might be more powerful than your 90s workstation, but if someone's scavenging technology they're more likely to find a Chromebook than a Sun.
As for what you're more likely to find in usable shape in a hypothetical collapse scenario, it probably depends on what kind of scenario you're talking about. Certainly vastly more Chromebooks exist than Suns, but the Chromebook's SSD only has a few months of data retention, so you probably won't be able to get it to boot if it's been sitting around unpowered for many years. All the Sun SPARCs are going to be in non-working order because their IDPROM batteries will have died, but some older 68000-family Suns like the 3/60 I theoretically still have are probably okay, because their IDPROMs are actually PROM rather than battery-backed RAM.
(Of course you also have to worry about capacitors drying out.)
What's vastly more common than Chromebooks, Suns, or GBAs, though, are Flash-based microcontrollers like the AVR family and 48MHz members of the STM32 family. (You can probably salvage a couple out of the wreckage of the drone that killed your parents.) And those will probably still be in working order, unlike anything SSD-based. I don't think Uxn is a good fit for those chips.
In a multiple-centuries sort of collapse scenario you also need to worry about the retention time of the NOR Flash in these microcontrollers. Hopefully if they lose their memory you'll still be able to rewrite it, but if the manufacturers used Flash to implement some supposedly-read-only memory, they might not bother to mention it.
In the collapse scenario we're actually in at the moment, GBAs, Nintendo DSs, and Chromebooks are all immensely more expensive than such microcontrollers. That seems likely to remain true even after the PRC invades Taiwan in a few years.
And while they're far more numerous, ultimately I think they're less likely to be used for personal computing. Sifting through the ruins, if you can find any functioning personal computer, you can get started immediately. Even if you don't have a compiler, you certainly have a web browser and write permissions. All you need to bring is the emulator spec.
That's an easier bar to clear than harvesting chips, a set of other working parts, gathering documentation for each, ensuring you have tooling and likely libraries for each, and most critically: enough existing, functioning tech to program it all. But if you already have that, you already have everything you need to compute without bootstrapping a new device. Not to say it wouldn't be worth the effort, but it's not an easier or alternative path to personal computing, just a path to share or persist it.
> Sifting through the ruins, if you can find any functioning personal computer, you can get started immediately. Even if you don't have a compiler, you certainly have a web browser and write permissions. All you need to bring is the emulator spec.
First of all, most collapse scenarios don't have an especially noticeable quantity of ruins. The Soviet Union collapsed in the 01990s; the GDP fell by half, the death rate skyrocketed, and they lost not only geopolitical influence but also significant parts of their high-tech industrial capacity. The People's Republic of China in some sense collapsed during the Cultural Revolution in the late 60s, losing significant parts of its cultural history, following the Qing dynasty's collapse in 01907. Syria is currently beginning to recover from a collapse into a civil war in 02011. Cambodia killed a quarter of its population and all its intellectuals in 01975–8 under the Khmer Rouge. The Imamate of Oman had been stable for over a thousand years until it collapsed under British bombing in 01957–9, bringing it under the control of the Sultanate of Oman, which still controls it today. About half of the Timbuktu Manuscripts were rescued from the onslaughts of Boko Haram after the collapse of Mali began in 02012, after centuries of being one of the greatest centers of learning in Africa; since then, that collapse has resulted in the overthrow of democracy by military coups in all three countries of the ASS. Suriname had a civil war in 01986–9.
If you want, you can read my slightly longer notes about most of those in https://derctuo.github.io/notes/pandemic-collapse.html; those are particular cases of recent collapses that I selected randomly in order to try to get a handle on the rough frequency with which countries collapsed.
Out of all of these cases, the only one with a really significant quantity of ruins to sift through was the Syrian Civil War, although there are a fair quantity of ruins in Ukraine now 33 years later, which you could argue in some sense resulted from the collapse of the USSR. Putin certainly does make that argument. I don't think I'll touch it any further.
If anything, booming economies like today's PRC might tend to have more ruins than collapsing societies, at least until a few generations into the collapse. People who can build new housing can afford to move out of the old housing; people who are struggling to survive have to patch the leaky pipes and the holes in the roof as best they can. The ruins all over the rural USA aren't the result of fentanyl and meth, but from people moving to the cities and selling their parents' farms to big agribusinesses.
So, let's get back to the scenario you proposed:
> if you can find any functioning personal computer, you can get started immediately. Even if you don't have a compiler, you certainly have a web browser and write permissions. All you need to bring is the emulator spec.
First, the likelihood of attempting something is only a weak inequality constraint on the likelihood of achieving it. Our intrepid hero is probably going to need those electronics hacking skills you're presupposing she lacks, because she's going to need to recap the PC's power supply and figure out how to run the computer off her car battery, which is a much easier task if your power supply needs to supply tens of milliwatts instead of tens of thousands of milliwatts. (Consider: my laptop charger died the day before last. It's a 65-watt USB-C charger and seems to be fully potted. Could you fix it? What would you have to know to build a replacement? How long will my laptop be useful without one?)
Second, where did you get the emulator spec? And, supposing you write a Uxn/Varvara emulator in browser JS, do you have existing ROMs to run on it? Or are you going to write the ROMs from scratch in Uxntal? If so, why not just write your applications in browser JS directly? My estimate is that you'll get roughly 20× as much useful computation per CPU cycle, and a browser pegging your CPU can easily double the baseline power consumption of a laptop. (In the case of this one, it goes from about 5 watts to about 10 watts.)
If you can get an emulator spec and ROMs, why not get a native-code IDE like Dev-C++ or Debian with Emacs from the same place you were getting those? A full Debian or NetBSD distribution is roughly one DVD.
If you want to prepare today for a possible future of scarcity, you can figure out how to harvest chips and put together tooling and libraries for them today.