Relay computers were a thing in the 1940s, for example Zuse's computers, Stibitz's machines at Bell Labs, the Harvard Mark I and IBM's SSEC. Vacuum tubes were o

Relay computers were a thing in the 1940s, for example Zuse's computers, Stibitz's machines at Bell Labs, the Harvard Mark I and IBM's SSEC. Vacuum tubes were orders of magnitude faster and killed them off, though. As far as using core rope with relays, you'd probably need to wrap each wire around the core many times (transformer-style) to get enough voltage to trip a relay. The raw signals from cores are really small and hard to detect even with ICs. https://en.wikichip.org/wiki/relay_computer https://en.wikichip.org/wiki/relay_computer