Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!nrl-cmf!cmcl2!polyof!john
From: john@polyof.UUCP ( John Buck )
Newsgroups: comp.unix.wizards
Subject: Re: Character echo at read time
Summary: lazy echo not all it's cracked up to be
Keywords: echo tty device driver line discipline
Message-ID: <371@polyof.UUCP>
Date: 2 Sep 88 01:32:10 GMT
References: <347@spies.UUCP> <670025@hpclscu.HP.COM> <24355@bu-cs.BU.EDU> <4477@mtgzz.att.com>
Organization: Polytechnic University, Farmingdale NY
Lines: 37

In article <4477@mtgzz.att.com>, dam@mtgzz.att.com (d.a.morano) writes:
> > article <12016@steinmetz.ge.com> davidsen@crdos1.UUCP (bill davidsen) writes:
> > >	one of the few things I like about DOS and VMS is that the
> > >characters are echoed as they are read, not as they are typed. This
> > >prevents display of info designed to be read "no echo."...
> I have used both styles of echo now for quite a while and I tend to
> prefer the style where the characters are echoed as they are read.
> There are many things that I can't stand in MSDOS and VMS but they
> got this thing right.  ...

Nah.  Type-ahead at read time can cause you lots of grief (lots more than
the default way Unix handles it.)  Spose you type three or four commands
head (I often do this, as do other's at our site).  I, for one, want to see
what the system got!  I don't want to find out later that I made a mistake
in typing the first "typed-ahead" command.  This could cause the subsequent
commands I type to not function properly!.  If you are going to delay
echo until read, you might as well forget about type ahead. (I, do not
type commands correct 100% of the time, more often than not, I make mistakes).

If "scrambled" input/output bothers you (and you are on a Berkeley system),
just do a "^R" to retype the input the system has so far... The only thing
that gets screwed up is the output, which you probably don't care THAT
much about anyway.

The other thing we did (for people who can't stand mixed input/output), is
to add an option to the tty line disc to not perform any output (ttwrite)
type calls to the terminal, if a line is in the middle of being typed.
(pos > 0).  As soon as you hit a RETURN, the output that may have backed-up
is flushed. (It's kind of like typing a '^S' before every character you
type ahead on a new line, and a '^Q' when the RETURN is hit.)
(Apollo does this on their serial-line driver...)

I'm curious to know: do you folks who tolerate "invisible" type-ahead
ever make mistakes in typing commands (ahead)?  If so, when do you detect
the mistakes?  Before it's too late?  How do you see what you are correcting?

polyof!john