[Nik]

I'm glad a previous post mentioned cat-whisker tech, saved me a lot of trouble...

IIRC, the first 'transistors' were point-contact. More recently, there's been interest in 'negative resistance region' materials for home-brew tunnel diodes...

(Care: These are 'NR region' materials, have a lazy-N output that can amplify if biased into 'active' region. They are not, Not, NOT perpetual motion, ZPE, antigrav etc etc... ;-)

FWIW, some-where in my accidental collection of electronic gubbins & widgets, beside the hollerith card-punch (!!), I have a primitive 4-function reverse-polish calculator which outputs to plasma-display nixie tubes. Those do not need vacuum-tube grade vacuum, but are still beyond the remit of a camp-fire glass blower...

Oh, and the case is full of 2nd-gen ICs, ie they are DIL not circular. I *think* they are DTL Diode Transistor Logic, which you could replicate with discrete components, rather than fully integrated TTL, ECL, CMOS etc...

I've also seen some hardened 'solid state' vacuum tubes, that resembled pottery rather than glass. And, I've seen logic done with gas-discharge tubes. Don't try this at home, folks, those voltages *bite*...

IMHO, you are looking at the problem backwards: I get the impression you are trying to boot-strap migrant herdsmen, and the answer is NOT PRACTICABLE. Even if you go for catswhisker tech, even if you could get the natural minerals to behave, make and place the delicate copper / gold / silver / iron filaments, even if you ran it all off 'baghdad batteries', even a simple, buffered sum-adder stage would fill a breadboard...

Yup, that's 1+1 --> 0 + 1_carry.

Um, before ICs were commonplace, I built free-roving robotic wheelies (and tank-trackies ;-) using only discrete components. There were a couple of 'priority' logic gates, a couple of delay timers, a flip-flop and some relay drivers crammed on to a circuit board. Similar in complexity to the sum-adder stage above, that was about my home-brew build limit.

If you wanted to do anything more serious, the set-up rapidly becomes non-luggable. Conceivably, the cellars of a mountain-perched monastery might be a good place to build it-- But now they're not herds-men/-women. IMHO, young ladies would make the best 'minders', they're more patient and nimbler fingered...

If you're talking post-post-industrial, then it is a different ball-game. A purely optical computer *may* be possible, and resemble nothing more technical than eg a 'crystal ball'. But, reflect light up into the 'south pole', and the globe may come alive with proximity sensors and holographic display...

We're into Clarkian 'indistinguishable from magic' country, yet perhaps less than a century away...

Given nano-tech, such marvels may be 'grown' from a 'seed' in a geode. The bigger, the 'wiser'...

Perhaps such 'crystal balls' may be capable of further growth-- Even from fragments.

Some-where between here, there and infinity, consider the possibility of bio-engineered plants that 'fruit' logic-module 'nuts'. Interconnections just need jewellery-grade metal-working tech. Output via bioluminescent 'nuts'...

Is this wildly off-track ??