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I stumbled across the history of the ASCII "delete" character recently: It's character 127, which means it's 1111111 in binary. On paper tape, that translates into 7 holes, meaning any other character can be "deleted" on the tape by punching out its remaining holes.

(It's also the only non-control ASCII character that can't be typed on an English keyboard, so it's good for creating WIFi passwords that your kid can't trivially steal.)




> It's also the only non-control ASCII character that can't be typed on an English keyboard

Don't count on it. There's a fairly long standing convention in some countries with some keyboard layouts that Control+Backspace is DEL. This is the case for Microsoft Windows' UK Extended layout, for example.

    [C:\]inkey Press Control+Backspace %%i & echo %@ascii[%i]
    Press Control+BackspaceāŒ‚
    127
    
    [C:\]
This is also the case for the UK keyboard maps on FreeBSD/TrueOS. (For syscons/vt at least. X11 is a different ballgame, and the nosh user-space virtual terminal subsystem has the DEC VT programmable backspace key mechanism.)


It's actually easier to add two spaces at both ends of the password :)


Wow, I never knew it was an actual character.


Sure, think of it this way: you're sitting at a terminal connected to a mainframe and press the "X" key; what bits get sent over the wire? The ones corresponding to that letter on the ASCII chart.

Now replace "X" with "Delete".




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