John von Neumann
loreprogramming
The mathematician whose 1945 EDVAC draft set out the stored-program architecture - instructions held in the same memory as data - that almost every computer still follows.
The draft circulated with his name alone on it, which is why the architecture carries it; the EDVAC group's work is in there too, and the attribution has been argued over ever since. The design decision that matters is the one people forget is a decision: code and data share a memory, which is what makes software possible and what makes buffer overflows possible, and the same property does both.
Also known as: von neumann, stored program