Path: utzoo!utgpu!water!watmath!clyde!att!mtuxo!mtgzz!dam
From: dam@mtgzz.att.com (d.a.morano)
Newsgroups: comp.unix.wizards
Subject: Re: Character echo at read time
Summary: type-behind
Keywords: echo tty device driver line discipline
Message-ID: <4477@mtgzz.att.com>
Date: 1 Sep 88 14:38:17 GMT
References: <347@spies.UUCP> <670025@hpclscu.HP.COM> <24355@bu-cs.BU.EDU> <4619@cbmvax.UUCP>
Organization: AT&T, Middletown NJ
Lines: 27

> 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." Fortunately
> 
>article <4619@cbmvax.UUCP>, ditto@cbmvax.UUCP (Michael "Ford" Ditto) writes:
> Yes!  Unix-style echo just plain sucks, in my opinion.  The right place

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.  Sometimes I refer to the preferred style 
(MSDOS/VMS) as 'type behind' because the characters are echoed behind 
(or after) the start of a read to the TTY.  Also, on UNIX(TM), the echoed 
characters can get displayed in the middle of a write(2) to the terminal.  
This serves to destroy background escape sequences that may be printing 
to the terminal from a background process using write(2) directly.  The 
resulting effect is garbage on the terminal display.  I would like to 
see a new line discipline that fixes these problems.  The VMS terminal 
driver seems to handle all of these subtle features beautifully.  When 
ever I have had to write a terminal driver, I always code for the 
preferred 'type behind' feature, the atomic write(2) operations, as well 
as other little good features.  

Dave Morano
Opinions expressed are mine alone and do not necessarily represent those
of AT&T Bell Laboratories.  UNIX is a registered trademark of AT&T.