From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Thu, 17 Aug 1995 06:01:55 -0400
From: Vadim Antonov avg@postman.ncube.com
Subject: More bugs.
Topicbox-Message-UUID: 17d5f1b4-eac8-11e9-9e20-41e7f4b1d025
Message-ID: <19950817100155.rmoryJZXv-gYb0SqV2zLlk3dCtVhlkIV8eg0RlqW-Bk@z>

>ohh no, rob has got it right with raw mode.  any other tty mode is
>a waste of time; just extra complexity for nothing.  this kind of
>thinking will result in a bsd-tty line discipline for plan9, job
>control, csh, dbx -- the horror, the horror...

Plan9 already has "line discipline" modules is several places
(devcons, 81/2, readln in auth utilities, telnetd), so instead
of replicating it would be useful to keep it in one place.

Raw mode and no echo mode are two different things and lumping
them together only makes all programs which read passwords
to be equipped with handling of kill and erase.

Most of the complexity of BSD and SysV line disciplines comes
from the history of the issue, as in v6 and v7 the hardware-specific
things were lumped together with the line discipline stuff.
Namely, ~ECHO had dual functon -- to handle half-duplex terminals
*and* to allow reading passwords.  Needless to say it was
inconvinient for both :)  RAW was "both ways", meaning no
conversion on output to terminals and no cooked processing
on input. That was very funny on terminals which needed 
output processing for things like Shift-In and Shift-Out
(yes, Virgina, there are people who speak funny languages
with letters like ya and tvyordyi znak).

For the hack value -- "no echo" on half-duplex hardcopy terminals
means typing over many times.  To my knowledge unix never
did that right.

If you don't like line disciplines you'd better not do
telnet-ing around.  There are different things (even TTYs)
on the Internet.  I respect the "simplicity is beauty" maxim
but tins on a string are arguably simplier than telephone.

Much of ugliness of present-day unices comes from the
under-functionality of the original system.  The holes were
plugged by other people, differently, and so the Babylon
started.  Later, some sorely misguided souls tried to "unify"
things by getting all variances into one system instead
of redesigning things to provide clear separation of functions.

Providing no functionality is not an answer, as people who
need to solve real problems in the real life will find ways
around it -- but it won't be pretty.  Not at all.

--vadim
(kremvax? yes, i used to run _the_ kremvax).