Newsgroups: comp.sys.atari.st
Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!wuarchive!zaphod.mps.ohio-state.edu!math.lsa.umich.edu!math.lsa.umich.edu!hyc
From: hyc@math.lsa.umich.edu (Howard Chu)
Subject: Re: uw (Unix Windows)
Message-ID: <1990Aug21.034333.11880@math.lsa.umich.edu>
Sender: usenet@math.lsa.umich.edu
Organization: University of Michigan Math Dept., Ann Arbor
References: <1315@nadia.stgt.sub.org> <1990Aug20.180400.254@math.lsa.umich.edu> <5594@quanta.eng.ohio-state.edu>
Date: Tue, 21 Aug 90 03:43:33 GMT
Lines: 48

In article <5594@quanta.eng.ohio-state.edu> rob@kaa.eng.ohio-state.edu (Rob Carriere) writes:
>In article <1990Aug20.180400.254@math.lsa.umich.edu> hyc@math.lsa.umich.edu
>(Howard Chu) writes: 
>]Both screen and uw require the BSD pseudo-tty and socket support. I
>]don't think anyone has reworked them for Sys V streams. You can go
>]ahead and try if you really want to.

>If that is the case, `screen' is pretty useless.  This functionality is
>already built into csh (look up the %, fg and bg commands).  A program like
>screen would be useful on something dumb like SysV, but it's a no-op on BSD.

Actually, in most cases I think screen is much more useful than uw. You
get the equivalent of an unlimited number of virtual CRTs. The program
uses curses to update the physical screen, and each task gets its own
virtual screen. Jobs running in hidden screens have their output buffered
until you select the appropriate screen. Unlike job control in the C shell,
which lets you spawn off multiple jobs from a single control terminal, all
demanding their input and spewing their output all over your CRT, screen
lets you spawn off shells, tip, telnet, or whatever program you want, each
with its own pseudo-tty as a control terminal. It's an incredibly useful
and flexible program. One feature I love is that you can detach a session,
and reattach it a later time *from anywhere else*. I can dial up from home,
start up screen, telnet to various places, start up long ftp sessions, etc.,
then detach and logout. Then I can hang up, do other work, go to my office,
whatever, and login to the screen host and reattach the sessions. Once you've
used this feature you'll wonder how you ever lived without it. (Especially
since this is a common feature of VMS...)

Since uw multiplexes all window output over the serial line simultaneously,
having lots of active windows will slow down performance on the current
window, and a particularly chatty session can grind everything else to a halt.
With screen, everything goes to its own screen buffer, and physical screen
updating always occurs at full speed. Hit a hot key to flip to another
window, and whatever needs to be redrawn is drawn, and you're there. Very nice.
Also, uw only provides adm-3 emulation, screen provides full ANSI X3.64 (vt100)
emulation. (Using termcap - it'll take advantage of nearly any feature you
can list in your physical terminal's termcap entry.)

[Are you convinced yet?]

It goes far beyond the job control of the C shell...


--
  -- Howard Chu @ University of Michigan
  one million data bits stored on a chip, one million bits per chip
	if one of those data bits happens to flip,
		one million data bits stored on the chip...