Miniaturization. The invention of the transistor in 1947 led to the production of faster and more reliable electronic computers. Transistors soon replaced the bulkier, less reliable vacuum tubes. In 1958, Control Data Corporation introduced the first fully transistorized computer, designed by American engineer Seymour Cray. IBM introduced its first transistorized computers in 1959.

Miniaturization continued with the development of the integrated circuit (a complete circuit on a single chip) in the early 1960's. This device enabled engineers to design both minicomputers and high-speed mainframes with huge memories. By the late 1960's, many large businesses relied on computers. Many companies linked their computers together into networks, enabling different offices to share information.

Computer technology improved rapidly during the 1960's. By the early 1970's, the entire workings of a computer could be placed on a handful of chips. As a result, computers became smaller.

Excerpt from the "Computer" article, The World Book Encyclopedia © 1999