On October 23, 1635, German astronomer and mathematician Wilhelm Schickard, who constructued the very first mechanical calculator, passed away. His famous calculator was able to perform additions and subtractions. For more complicated operations, it provided so-called Napier bones, named after the Scottish mathematician John Napier, who came up with the idea of logarithms. Although it is widely believed that the first mechanical calculating device was created by the French mathematician Blaise Pascal in 1642. However, that distinction actually belongs to Wilhelm Schickard.
On November 27, 1852, Augusta Ada King, Countess of Lovelace, who is considered to be the world's very first programmer, passed away. Every student of computer science should have heart of the world's first programmer, Ada Countess of Lovelace, assistant to Charles Babbage, inventor of the very first programmable (mechanical) computer, the analytical engine.