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Re: Replace with CR


From: Pascal J. Bourguignon
Subject: Re: Replace with CR
Date: Mon, 06 Jul 2015 12:34:38 +0200
User-agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux)

"Gian Uberto Lauri" <saint@eng.it> writes:

> Stefan Monnier writes:
>  > > Again, there's no such thing as ENTER.  The key is RETURN.
>  > 
>  > FWIW, my keyboard (US thinkpad) has no "RETURN", but it does have a key
>  > labelled "Enter".
>
> I have "Return" on my old VIC20, but I doubt Emacs will be ever ported
> there...
>
> "Return" was a tty-derivative labeling and was once common, even when
> it sent a LF o CR/LF[1] pair. 

NO. THE "RETURN" KEY NEVER EVER SENT A LINE-FEED CODE! Not even in CR-LF
pair.  It only sent a CARRIAGE RETURN code.

It is the system that echoed this carriage return along with a line feed
(or just a line feed when local echo was activated).  And in the case of
unix, it is the keyboard driver that translates the CARRIAGE RETURN code
it reads into a LINE FEED in the buffer (and even, only according to the
tty configuration).  In linux, check n_tty_receive_char and
do_output_char in drivers/tty/n_tty.c



> Enter is much common now and closer to
> semantic the keys has today for most computer users. Enough common to
> build jokes on, see the two strips I posted.
>
> [1] for those who still do not know it: the pair is CR/LF and not
> LF/CR because on old TTY the carriage return was a longer operation
> that could be controlled without keeping the tty controller busy: you
> could start the head carriage, and while the it was going home move
> the paper drum one line.

-- 
__Pascal Bourguignon__                 http://www.informatimago.com/
“The factory of the future will have only two employees, a man and a
dog. The man will be there to feed the dog. The dog will be there to
keep the man from touching the equipment.” -- Carl Bass CEO Autodesk


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