Meaning behind Control-G

[Lars Brinkhoff]

> > > > What does C-g mean? Why the sequence C-g specifically? I think
> > > > the disconnect may be that C-g appears outwardly meaningless.
> > > I will ask Greenblatt -- he might remember.
> > I suspect there is no deep meaning behind it, the BEL was common way
> > back then to mean abort, or alert.  TECO and DDT both used C-g for
> > abort,
> Are you confident of that?  I don't remember, but if your memory is
> clear, that is probably the reason.

I remember it clearly, because I use ITS DDT almost daily.  TECO, not so
much but it's easy enough to verify.

Now, why TECO uses Control-G for "quit", I don't know.  ASCII "BEL" as
an "alarm" is a plausible theory, but hard to verify.  In general
there's no strong link between control characteras as inputs and their
corresponding output behaviour.

I see no control character commands here, so maybe Control-G wasn't
in use with PDP-1 TECO:
http://www.bitsavers.org/pdf/mit/rle_pdp1/memos/Murphy_PDP-1_TECO.pdf

I don't see Control-G Here either, so maybe it was added after 1964:
https://github.com/larsbrinkhoff/its-archives/blob/master/ailab/pdp6-memo-2.pdf