This document summarizes the history of computing devices from ancient abacuses to modern computers. It describes the progression from mechanical calculators using beads and rods in 3000 BC, to early electromechanical computers using vacuum tubes in the 1940s-1950s, to transistor-based computers in the 1950s-1960s, integrated circuit computers in the 1960s-1970s, microprocessor-based computers in the 1970s-1990s, and modern computers incorporating artificial intelligence capabilities since the 1990s. Key inventors and their contributions to advancing calculator and computer technologies are highlighted at each stage of development.