The document traces the history of computers from ancient counting devices like the abacus to modern machines. It discusses early mechanical calculators invented by Pascal and Babbage in the 1600s-1800s. The first modern computers of the 1940s-50s used vacuum tubes and were developed by Aiken, Eckert, Mauchly and others. The transistor was invented in 1948, making computers smaller and more reliable. Personal computers emerged in the 1970s with the Altair and IBM PC, using graphical user interfaces pioneered by the Apple Macintosh in 1984. The document also outlines the five generations of computers and their defining technologies.