> I've thought about this, more in the context of post-apocalyptic computing rather than trust, FWIW.
Post-apocalyptic computing is one possible motivation to look at this, but other reduced-tech settings like a fully independent Mars colony also simply cannot function without a way to fab simple IC logic. That, or we’re happy to go back to early Apollo era tech levels.
RE: computers from scratch in the absence of IC fabrication. I think our best chance is vacuum tubes. Mechanical relay computers seem to have been phased out in favour of vacuum tube solutions pretty quickly, so I guess there must have been some compelling reasons to do so (my guess - speed and failure rate of individual switching components). Couple that with old-school electromechanical tech for IO/industrial sequencing, several K of delay line/core/Williams Tube memory, and you’re golden.
Sam Zeloof is doing great things: http://sam.zeloof.xyz/
> Making even the simplest 6502 equivalent by yourself is impossible, forget more complex projects. I feel like this should be urgently addressed, given how important computing is.
I've thought about this, more in the context of post-apocalyptic computing rather than trust, FWIW.
If I were really going to make my own computers from scratch I think clockwork (Clock of the Long Now) or fluidics would probably be the way to go. Maybe electro-mechanical (relays, etc.) or vacuum tubes? We did pretty well with the abacus and the slide rule, eh?