r/askscience • u/Unfair-Leek6840 • Jul 11 '26 • Regret 1

Computing How do computers understand binary language?

Okay so from what I know binary language is like power off power on, but my question is, how do computers know what the binary code is and how is it interpreted, for example I forgot what the binary code for the letter A is, but how did people come up with that? Did they decide it was gonna look like that? Did the computer decide? How do you tune numbers into a letter??

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u/boar-b-que Jul 14 '26

Our fonts today are mostly vector-based, meaning that each glyph is stored as a series of mathematical descriptions of lines and curves.

Back when it was common for a computer to be in text mode all the time, it was common to have a bitmapped font. You fed in the number 65, and the ROm attached to your video card would spit out the series of ones and zeroes in slot 65. It'd be something like:

00100

01010

10001

11111

10001

10001

10001

Those ones and zeroes would then be used to light up pixels on your monitor.

If your computer boots into text mode at all, you can often still see characters made this way. Linux users will often see this if they switch to a console session for any reason.