When the world’s first programmable electronic general-purpose computer was unveiled in 1946, the six brilliant women who actually programmed it were not even invited to the celebratory dinner. This episode tells the story of ENIAC, born from a desperate WWII crisis to calculate artillery firing tables, and the human computers whose mathematical labor made the machine think. We explore the hardware of 18,000 vacuum tubes, the engineering battle against burning filaments, and the grueling physical work of programming with cables and switches.

We follow how Kay McNulty, Betty Jean Jennings, Betty Snyder, Marlyn Wescoff, Fran Bilas, and Ruth Lichterman invented the discipline of programming from scratch, only to be dismissed for decades as refrigerator ladies. We also cover ENIAC’s first real mission for the hydrogen bomb, the Monte Carlo method, the stored-program modification, and the court case that voided the ENIAC patent and placed the electronic computer in the public domain.

• The artillery firing table crisis and the human computers who solved it
• How vacuum tubes acted as electronic gates to perform calculations
• The physical, blueprint-free work of wiring programs by hand
• The refrigerator lady myth and Kathryn Kleiman’s rediscovery in the 1990s
• The Honeywell v. Sperry Rand ruling that invalidated the ENIAC patent