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From: guy@gorodish.UUCP
Newsgroups: comp.unix.questions
Subject: Re: Multiscreen on Unix
Message-ID: <20837@sun.uucp>
Date: Wed, 10-Jun-87 15:59:11 EDT
Article-I.D.: sun.20837
Posted: Wed Jun 10 15:59:11 1987
Date-Received: Sat, 13-Jun-87 05:36:41 EDT
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> Has anyone done anything like this with STREAMS-oriented tty drivers?
> It seems to me that windows/multiple screens would be relatively
> easy to implement by just PUSHing an appropriate module onto the
> stream that controlled your physical terminal that kept track of
> what was on your (physical) screen at all times, similar to curses.

"Relatively easy"?  "Similar to curses"?  "curses" is a pretty big
library, and even something just handling this would be pretty big.
It would either have to implement a virtual terminal, and support
*lots* of different kinds of physical terminals, or would have to
keep track of the screen image by understanding how the physical
terminal works, and would still have to support lots of different
kinds of physical terminals.

STREAMS modules live in the kernel, and I don't want something that
big living in my kernel.  (There are enough big things living there
already.)  Furthermore, it would also have to maintain a copy of the
screen, which means even more big things in the kernel.

Sorry, but putting this into a STREAMS module would be the wrong
thing to do.  Pseudo-ttys make much more sense, since most of the
support can be moved into user mode.  Under the right circumstances,
a STREAMS-based tty driver could make it easier to do pseudo-ttys; a
pseudo-tty might be something similar to a streams pipe, with any
other modules pushed atop the "slave" side.
	Guy Harris
	{ihnp4, decvax, seismo, decwrl, ...}!sun!guy
	guy@sun.com