Pascal invented the first adding machine. Now a machine can do something that was once considered an intelligent task.
Babbage developed a machine that could solve equations. He never finished his work because the machine needed very accurate gears in order to work. His machine can be used today. Today's concept of computing incorporates Babbage's ideas (CPU, memory, I/O).
Ada, Countess of Lovelace wrote comments on Babbage's design. She had developed a "programming language" for the machine that was never built. She is known as the first programmer. The Countess of Lovelace posed the question of whether computers can think and answers that they can't because they can do only that which we tell them to do.
Baldwin patented a calculating machine to handle commerce.
Hollerith designed a punch card for the census. You would have to float the cards over liquid mercury. Needles would go through the hole and complete the circuit. They finally found out that the mercury was poisonous and could not use it anymore. Hollerith eventually founded IBM.
Von Neuman allowed us to store programs in the machine rather than constantly rewiring the machine. This was the beginning of modern software.
Turing came up with the concept of artificial intelligence.
At first no two computers were built alike. Today there are thousands of the same computer. There is large scale parallelism, neural net research, and commercial applications of artificial intelligence.