Every now and then I think about those sci-fi stories where they discover forgotten advanced tech that just whirls and hums and then starts to work when the protagonists appear. Thinking how hard it would be pull off.
I can barely imagine building something that would wake up after twenty years (say, raspberry pi with some extremely simple HW functions, e-ink display and a power source(?)). How to make something like that last for centuries or millennia? I come back to this idea more often nowadays.
I’ve written embedded software that is likely to be running still in 2040’s, but device it runs on might get replaced many times over time, and the power is not an issue in that context.