Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cwjcc!hal!ncoast!allbery
From: allbery@NCoast.ORG (Brandon S. Allbery)
Newsgroups: comp.unix.wizards
Subject: Re: TTY, speak now, or forever
Message-ID: <1989Oct24.011505.20515@NCoast.ORG>
Date: 24 Oct 89 01:15:05 GMT
References: <216100015@s.cs.uiuc.edu>
Reply-To: allbery@ncoast.ORG (Brandon S. Allbery)
Followup-To: comp.unix.wizards
Organization: North Coast Public Access UN*X, Cleveland, OH
Lines: 40

As quoted from <216100015@s.cs.uiuc.edu> by voss@s.cs.uiuc.edu:
+---------------
| I am just starting a small project to write a "tty" driver for a research
| operating system.  I got the word today that I should NOT clone the BSD/SYSV 
| versions.  Quote "no IOCTLs".  Basically, I have an almost clean slate to 
| work with.  Functionally, I intend to base my work roughly on BSD `man 4 tty`.
| (Because a friend will be implementing a Unix compatibility mode on top.)
| Is there anything NOT in `man 4 tty` that you think I should put in my driver?
| Is there anything IN `man 4 tty` you think I should NOT put in my driver?
+---------------

Consider starting with the System III/V setup instead.  But use your chance to
do it better.

(1) Implement at least some of the Berkeley "new tty" stuff as part of the
    "local flags".

(2) The System III/V setup is much more orthogonal than the Berkeley one... but
    it still has warts.  Now is a good time to correct them and make it *fully*
    orthogonal.

(3) Speaking of which:  kindly separate VMIN and VTIME from VEOF and VEOL.

Job control (hacks...) can be added onto such a structure if you choose.  The
maelstrom of V7/BSD arrangements (separate ioctls for four different "kinds"
of items, which should be reduced to AT LEAST two and possibly a USG-ish
single structure -- although that is arguable) is a bit ridiculous, in my
opinion.

Whatever you do, consider that you are possibly building for the future and
*do* *it* *right*.  Both the current Unix tty interfaces have problems which
cry out to be addressed.

++Brandon
-- 
Brandon S. Allbery, moderator of comp.sources.misc	     allbery@NCoast.ORG
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