On Wed, Feb 21, 2001 at 06:29:29 -0800, Marco Cimarosti wrote:
> What is the function of ASCII control code 0x7F (DEL) in text
> interchange?
>
> Particularly, what effect or interpretation might it have in
> communication protocols, terminal protocols and, especially, inside
> text files?
>
> My interest is about the function of this character in
> *contemporary* platforms and software, although I wouldn't dislike
> historical information, as far as it is clearly flagged as such.
AFAIK, the history is that on punched media (cards, paper tape) DEL
was used to delete a character as it was represented as holes in all
positions.
For paper tape the following demonstrates it nicely:
$ echo -ne '\177' | /usr/games/ppt
___________
| oooo.ooo|
___________
On DEC (and, I belive other) terminals the <-- "Rubout" key (PC
keyboards has "BackSpace" key in this position) generates DEL. So
emacs, The One True Editor :-), uses ^H key (i.e. backspace) for help
- which causes a lot of confusion for new users who have PC keyboards
that generate backspace (^H) for <-- key.
SY, Uwe
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