SUMMARY: Redirecting second Xsun output to remote screen

From: Alberto Ferrari (
Date: Tue Oct 12 1999 - 18:54:32 CDT

Dear Friends:
I posted this note almost a year ago, with the promise to summarize the
results. I'm deeply sorry it took me so long, and would specially like to
apologize to the people who answered me.

A couple of considerations:
Win98 has built-in support for dual-head displays, so the question is
irrelevant in this specific case. W95 hast not (as far as I know), and NT
has after applying some strange package.

The software the instruction was intended ran in dual-headed SUN machines,
so I expected to reproduce a sense of the original hardware in the
Conference Room. This way, the instructor would have about the same setting
as the original work environment.

Thank you all

We have half a dozen double-headed Ultra machines (two frame buffers - i.e.,
screens on each) running under Solaris 2.5.

We use to start the local Xserver with:
/usr/openwin/bin/Xsun :0 -nobanner -dev /dev/fb0 -dev /dev/fb1 -auth

In this case, the Xserver starts both screens at
once and let us work almost transparent with the mouse, while moving it from
one screen to the other.

* The situation: *
My boss arranged to have a course with dual-headed machines in the
Conference Room, which has a couple PC's with XServer installed and one huge
electronic overhead projector, taking its video input right off the video
card and projecting it to the wall. Both PCs are available through the

* The question: *
Is it possible to redirect one of the screens to another Xserver, and still
keep one single point-of-control for the entire environment/application?

I thought we should be able to display the first
screen in the projector (:0) and redirect the second one to another Xserver
for it to display in a local

If I couldn't, I would arrange a couple of
instances for the application to develop into each PC private Xserver, and
try to synchronize them by hand.

PD: I did my homework and tried everything I could possible think of: man
pages (where are Xsun's? - didn't find them, not even in sunsolve!), former
postings, sunsolve...

From: Brooke King +1.505.844.5936 both voice and fax

Sun commercialized some software from here called ICE. ICE allows
one system's X-windows to be displayed on multiple systems and to
take input from them. It might be of help.

Frankly, I must not understand your situation. If the course is
in the classroom, wouldn't you want all displays of course-
related windows in the classroom and not care about whether they
display on the execution machine? If that's the case, then there
is no issue about redirecting output from the execution machine;
it's just a question of using the PC (dual headed or not) as
X displays. Does the PC Xserver software support dual heads? I
don't know, but that is not an issue in most classrooms because
what is projected is the output for one screen only, and that
screen is usually also displayed on one of the PC's monitors.


From: David S. Foster (

Check out the Xvfb (virtual frame buffer) program available with the X11R6 installation:

XVFB : Virtual Frame Buffer (and man page)

This might solve your problem. It's a way of allowing programs requiring an X server to run without using the "default" X server, by creating a virtual frame buffer in memory.


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