1. The abacus was the earliest known computing device used for counting and calculations. Charles Babbage then created the Analytical Engine, the first automatic computer, in the 1830s. 2. Modern computers evolved through five generations. The first generation used vacuum tubes which produced a lot of heat and consumed excess energy. Transistors replaced vacuum tubes in the second generation. Integrated circuits were introduced in the third generation, along with keyboards, mice and monitors. The fourth generation saw the introduction of microprocessors and personal computers. The fifth generation began using artificial intelligence and natural languages, with devices like laptops and palmtops.