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by bubblicious
2452 days ago
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Fun fact: the delete character was designed to be all 1s in order to allow for human errors: "If a character was punched erroneously, punching out all seven bits caused this position to be ignored or deleted" [1] [1] https://en.wikipedia.org/wiki/Delete_character |
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When you were punching a paper tape, you couldn't "delete" a character, unless you wanted to risk cutting and splicing the tape, and good luck with not jamming the reader.
But by convention, a RUBOUT character (with all holes punched) would be ignored. So if you made a mistake you could backspace the tape and punch RUBOUT.
RUBOUT had another useful purpose. It's well known that the DOS/Windows line ending convention (CR/LF: Carriage Return/Line Feed) comes from the days of Teletypes, but what is less known is that we didn't actually just punch CR and LF. Sometimes on a Teletype that wasn't perfectly maintained, the CR and LF would not give enough time for the carriage to settle on column 1.
So we always punched RETURN, LINE FEED, and RUBOUT. The RUBOUT would be ignored, and it added a little extra time for the carriage to settle into place and not get a blurry character in the first column.
Here's a nice picture (although the discussion isn't completely on the mark):
https://www.reddit.com/r/MechanicalKeyboards/comments/2v3k0p...