QIS needs an X server to do drawing.  The X server to be used can be the X server 
running on the machine where QIS is running (let's call this MAIN).  It can also 
be the X server running on the machine where a user is using to remote login to 
the QIS machine (let's call this LAPTOP).  In fact, theoretically, it can even 
be any X server running on any machine in the network.


So, to specify which X server to use, $DISPLAY is set to the machine name or IP 
address together with the screen/graphics card number.  e.g.


export DISPLAY=MAIN:0
OR export DISPLAY=LAPTOP:0
OR export DISPLAY=123.456.789.10:0


THEN RUN
qis64 -port 12345 &


That's the simple case.


Now more details for special cases.  Imagine QIS is running on a server machine
(MAIN) running in the back room, this server machine (MAIN) might not have a 
monitor connected to it.  If that's the case, X server MIGHT or MIGHT NOT be 
running on MAIN.  If X server is running, then simply set $DISPLAY to MAIN:0 
and then run QIS; QIS should be able to run continuously until an Exit command 
is sent to it.  If X server is not running on MAIN and cannot be run on MAIN, 
then the only way is to use another machine's X server.


To use another machine's X server, normally, the X server running on the remote 
login machine is to be used (LAPTOP).  Simply login to the QIS machine MAIN, 
set $DISPLAY to LAPTOP:0, then run QIS.  Now, QIS is "connected" to the X server 
on LAPTOP and running in the background of MAIN.  If the user logout of MAIN, 
QIS should still be able to run on MAIN as long as the X server is running on 
LAPTOP.  If X server on LAPTOP is down, either because X server on LAPTOP is 
stopped or LAPTOP is shutdown, then QIS would die because it lost the connection 
to the LAPTOP X server.


The only other way to keep QIS running on MAIN is to use yet another machine's
X server and that other machine's X server has to be continuously running.


export DISPLAY=ANOTHER_MACHINE:0
qis64 -port 12345 &


On a related note, if QIS drawing is not required (just open a GDSII file and 
always get vector data), then QIS could be started with -nodisplay and QIS 
would not need $DISPLAY to be set and it would connect to an X server.  e.g.


qis64 -port 12345 -nodisplay &