[GreenKeys] Original meaning of ASCII codes

[jhaynes@alumni.uark.edu]

I think one reason the computer people messed things up so badly (e.g.
using ctrl-D for end of file when there is already a file separator
assigned) is that the early Model 33 machines couldn't generate all the
characters.  Also they didn't like to use a three-finger combination 
(e.g. shift-control-X) for frequently used functions.  Then the article
doesn't make a clear distinction between 1961 ASCII and 1968 ASCII.
Some things like the RU answerback present in 1961 ASCII were recognized
as bad ideas by the time ASCII was revised.  And some things were just
never well agreed upon, so the characters were just left in there.
CAN for example: does it cancel the previous character, or the previous
message, or the previous line, or what?  (In Baudot you cancel a 
fragmented message with some characters I don't remember followed by
BUST THIS.)

There is some material on Bob Bemer's web site.

Backspace has been a problem all these years.  In hardcopy terminals there
was the concept of backspace and strike over as a way to get some funny
characters such as the Nordic o with a slash through it, or German u with
an umlaut over it.  But on video terminals backspacing simply moved the 
cursor backwards; and if you then typed another character it replaced the
previous one rather than adding to the pixels that were already there.
We really needed an equivalent of the backspace-and-erase key on 
typewriters, a separate character from backspace.  The choice of DEL for
this purpose is of course completely illegitimate and presumably results
from some computer people who had no concept of backspacing and rubbing
out paper tape.