Paul E Condon wrote: > Bob Proulx wrote: > > DEL 0x7f is a control character. It is not a printable character. > > And its history is interesting. > > The original name for DEL was RUBOUT. It was used by telegraphers to > rub out a mistaken punch in a paper tapes that they were preparing off > line, prior to actual transmission. This is a very practical use and > the code with all holes punched was the only one that served this > purpose. Also, RUBOUT produced a nice tear strip across the tape.
Yes. Note that I did say that its history is interesting. :-) It is why there is both backspace and delete on the keyboard. So that you can backspace to the characters you want to delete and then you can delete them. But that meant that when 0x7f characters encountered on input were ignored since they were characters that had been deleted. > On a teletype, every code caused the print mechanism to cycle, so in a > special mechanistic sense, rubout was intended to be "printable." Printable on paper tape, yes, but if you loaded the paper tape back into the system then you found that the deleted characters had disappeared. :-) A fun trip down memory lane... And in the play of semantics. Bob
signature.asc
Description: Digital signature
