cosell@Bbn-Unix@sri-unix (09/08/82)
From: Bernie Cosell <cosell@Bbn-Unix>
Date: 5 Sep 1982 3:23:32 EDT (Sunday)
In a recent revision of the ASCII standard (where `recent' probably
means between five and ten years ago), `Newline' is a defined
alternate meaning for'\12'. I haven't seen the real spec in
a long time now, but as I recall they had the good sense to take
all of the `standard' usages of various control chars and make
them alternate meanings for the chars. (for example, I believe that
the flow control functions of ^s and ^Q are now explicit).
In some sense, this means that the VT100 folk got it wrong.
The key on the vt100 that was clearly intended
to carry the `newline' function sends 015 instead of 012. As I understand
the spec you have two choices for `newline': 015-012 or just 012.
DEC (and a lot of others, of course) mostly `made up' the convention
of using 015 for newline. It hardly has a persuasive argument in
favor of it beyond the largeness of the key on many terminals.
[historical note: I believe that this `convention' came into being
in the days of halfduplex model 33's: if you had the user use
CR for the newline function, the system had merely to echo a LF
and everything was fine. If you had the user use LF for newline,
then the system had to echo CR RUBOUT, since it took a char of
padding to do a CR, normally nmasked by the LF character (didn't you
ever wonder why the sequence is CR-LF and not vice-versa?). I've
fooled with such a scheme and I can report that the extra char
is really a pain it can really upset you rhythm, dsuch as it can be on a
110 baud, noisy, mechanical kludge.]
/Berniecak@Purdue@sri-unix (09/10/82)
From: Chris Kent <cak@Purdue> Date: 8 Sep 1982 12:05:45-EST Well, DEC isn't alone. ADDS also puts a 'newline' key on their terminals that sends a \015; it sits right next to the 'line feed' key, which sends a \012. Perhaps this is why so many of my users have been confused when expected to type a 'newline' to get nroff to continue output, and get nothing when they hit that key (since -nl is set on the output device...) chris
ecn-pa:bruner (09/11/82)
There are terminals for which "newline" is neither a 012 or a 015. Ever used a Superbee? I'm stuck with a couple of these kludgey monsters (I could write pages and pages about the problems they have, and how no two of them seem to use the same cursor control sequences, etc.), and they have a nice large NEWLINE key which generates not CR or LF, but US (037). This means the tty driver and all programs that use raw mode (like "getty") must contain special-case code to convert 037 to 012. One of these days I'm going to get an axe and put them out of my misery. --John Bruner Purdue/EE