John was born in the 1930's. The first major event of his life is WWII. He was very young when WWII broke out, and he was able to avoid the draft. Our system model tries to recreate the process of how John fixed a radar during the war period. He was an amateur aeronautical engineer before being recruited by the navy. After he joined, he became an electrical engineer and started learning about radars. Radars, according to John, were top-secret technology that no other country had. John learned about radars for 10 months before the war ended, meaning he was involved in the war during the last year: 1944-1945. 

In 1943, Mussolini surrendered after his government fell in Sicily and Italy

June, 6, 1944, celebrated as D-day, where enormous Allied forces invaded Europe from the beach of Normandy. This resulted in Hitler sending his remaining forces to fend off the invasion. 

February, 1945, an intense aerial bombardment was followed by a land invasion of Germany. 

May, 8, 1945, Germany formally surrendered

September, 2, 1945, Japan formally surrendered on the USS Missouri in Tokyo Bay 

Source : https://www.history.com/topics/world-war-ii/world-war-ii-history