Page 11 - UNI 101 Computer Science Handout.

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binary digit is a 0 or a 1. Thus, rather than having to account for the 10 possibilities of a decimal digit,

one can represent a binary digit with only a single device that has two possible states. For example, one

could represent each binary digit with a simple on/off switch, where the “on” position represents a 1
and the “off” position represents a 0:

Similarly, in the Atansoff-Berry Computer, each binary digit could be represented with a single vacuum

tube. Thus, the number “eighteen” could be represented with only 5 vacuum tubes, instead of the 20
the ENIAC required:

Likewise, the number “two hundred fifty-five” could be represented with only 8 vacuum tubes, instead

of the 30 that ENIAC required:

Thus, in exchange for the cryptic unfamiliarity of binary representation, computer engineers gained an

efficient way to make electronic digital computers through the use of two-state electronic devices. Just

as radios with vacuum tubes were superseded by “transistor radios” beginning in the 1950s, so this “first
11 Academic Year 2025/2026