The document provides a chronological overview of milestones in the development of computing technology from 2500 BCE to 1939:
- The abacus, developed in China around 2500 BCE, was the first tool used for calculation. Static electricity was described by the Greek philosopher Thales of Miletus around 600 BCE.
- The Romans used an abacus with pebbles in 500 BCE. The slide rule was invented in 1633. Blaise Pascal invented the mechanical adding machine in 1642.
- Gottfried Leibniz developed a gear-based calculating machine in 1671. Charles Babbage invented the first programmable mechanical computer, the Analytical Engine, in 1833.
-