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etaioinshrdlu | 3 months ago

"Before microchips existed, computers were built with mechanical relays." Should probably say something about vacuum tubes as well!

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analog31|3 months ago

And discrete transistors. Now that my curiosity is piqued, I found this nice timeline:

https://www.computerhistory.org/timeline/computers/

It looks like transistorized computers were dominant at the point when integrated circuits were introduced.

JKCalhoun|3 months ago

Interesting: the entry for the Apollo Guidance Computer (AGC) indicates it used integrated circuits—I had remembered hearing it used RTL (resistor-transistor logic).

It turns out both are true [1]. The "integrated circuits" were sort of "flat-packs" of RTL circuits. I had forgotten that early IC's were not quite what we envision today. Regardless I suppose ICs were RTL before they were TTL (before they were CMOS, etc.).

[1] https://en.wikipedia.org/wiki/Apollo_Guidance_Computer#Logic...

hbrav|3 months ago

And before that with gears! (With limited success.)

aebtebeten|3 months ago

I like how the 1937 "Model K" adder is literally on a breadboard.

(are those knife switches in the upper right?)