Mill and store (Babbage)
Babbage's split of the Analytical Engine into a calculating part and a holding part — the same line later drawn between the ALU and memory.
When Charles Babbage began designing the Analytical Engine in 1837, he divided it into two organs and borrowed the words from the textile trade, the same industry he took the punched card from. The mill performed the four arithmetic operations on whatever numbers were fed into it. The store held numbers between operations — a planned thousand numbers of fifty decimal digits each, in columns of toothed wheels. Numbers were milled; finished goods were stored.
The split was not obvious. The Difference Engine had none: there the arithmetic lived inside the storage registers themselves, the way a cash register works. By separating where the computing happens from where the numbers live, Babbage got something categorically different — a machine whose instructions must name which numbers to fetch, which in turn demands addressing, conditional jumps and loops. The von Neumann architecture draws the same line a century later, with the added idea that the program may live in the store too.