Yeah, try explaining “drive C:” to a kid these days, and why it isn’t A: or B: …

Of course software developers are still stuck with 80 column conventions even though we have 16x9 4K displays now… Didn’t that come from punchcards ???

Come for punchcards, stay for legibility.

80 characters per line is an odd convention in the sense that it originated from a technical limitation, but is in fact a rule of thumb perfectly familiar to any typesetting professional from long before personal computing became widespread.

Remember newspapers? Laying the text out in columns[0] is not a random quirk or result of yet another technology limitation. It is the same reason a good blog layout sets a conservative maximum width for when it is read on a landscape oriented screen.

The reason is that when each line is shorter, the entire thing becomes easier to read. Indeed, even accounting for legibility hit caused by hyphenation.

Up to a point, of course. That point may differ depending on the medium and the nature of the material: newspapers, given they deal with solid plain text, limit a line to 40–60 characters; for programming it may be wider due to often longer “words” and other factors and conventions like syntax highlighting or indentation, and when dealing with particularly long identifiers (I’m looking at you, CNLabelContactRelationYoungerCousinMothersSiblingsDaughterOrFathersSistersDaughter) wider still.

[0] Relatedly, codebases roughly following the 80 character line length limitation unlock more interesting columnar layouts in editors and multiplexers.

It did, but 80 columns also pretty closely matches the 50ish em/70ish character paragraph width that’s usually recommended for readability. I myself wouldn’t go much higher than 100 columns with code.

While 80 characters is obviously quite short, my experience is that longer line lengths result in much less readable code. You have to try to be concise on shorter lines, with better phrasing.