From: utzoo!decvax!cca!dan@Bbn-Unix@sri-unix
Newsgroups: net.unix-wizards
Title: Re: More getty questions
Article-I.D.: sri-unix.3408
Posted: Tue Sep 21 22:39:07 1982
Received: Wed Sep 22 07:16:59 1982

From: Dan Franklin 
Date: 17 Sep 1982 11:33:27 EDT (Friday)
I believe it's mostly historical.  Some terminals (or at any rate,
one terminal, the TTY 37) use a newline key instead of
a CR key, and interpret an LF as a newline sequence.  Getty identifies
those terminals by looking at the character terminating the username
line to see whether it's a CR or an LF.  It can't do that if CRMOD
is set, because unfortunately (as with most of the UNIX tty modes)
it affects both input and output, and there's no way to map LF to CRLF
on output without also mapping CR to LF on input.

If you have no TTY 37s you can probably get by without this feature.