1. COMPUTERS OF THE PAST By Leif Fossmo

2. THE VACUUM TUBE (1951-1958) Created in 1947 by Mauchly and Eckert, called the ENIAC Used to calculate the U.S. census Small electronic tubes the size of lightbulbs were used to calculate data Magnetic cores consisting of tiny donut-shaped rings which were strung on intersecting wires provided memory, until 1957 when magnetic tape was created Home

3. THE TRANSISTOR (1959-1964) Small device that transfers electonic signals across a resistor, created in 1947 by John Bardeen, Walter H. Brattain, and William Shockley Revolutionized electronics, computers in particular Much smaller than vacuum tubes, needed no warm-up time, consumed less energy, generated less heat, more reliable Incorporated into computers in the late 1950s Home

4. THE INTEGRATED CIRCUIT (1965-1970) Complete electronic circuit on a small chip of silicon Silicon is one of the earth’s most abundant elements and is found in common beach sand as well as almost all rocks and clay Silicon is a crystaline substance that conducts an electric current when it has been doped with chemical impurities IBM 360 series was the first to take advantage of these new integrated circuits Home

5. THE MICROPROCESSOR (1971-NOW) Microprocessor became the evolved form of the integrated circuit Became commercially available in 1971 Home