Machines That Remember
Memory was once a room full of delicate hardware, and every bit was an engineering achievement.
Early computers could calculate, but remembering was expensive. Instructions and data lived in punched cards, delay lines, drums, or arrays of tiny magnetic cores. Each approach had its own tradeoffs in speed, cost, and reliability. The search for memory shaped the architecture of the machines as much as the arithmetic did.
The shift from external media to internal storage changed what a program could be. Once instructions and data could live in the same addressable space, programs became more flexible and machines became more general. The idea seems obvious now, but it took years of engineering to make it practical.