[Hampshire] Starting an application directly after power on …

I have an application written to run on an Ubuntu installation that monitors
some external signals from an i/o card and displays them in a X window with
no window manager.

The system does not need a keyboard because it's only purpose is to measure
and display and I would like the PC to enter the application on power up. (I
have a method for shutting down from an external signal)

Without really understanding what is going on I have had partial success by
changing the entry in innitab that launches getty to launch xinit with the
application name i.e.

1:2345:respawn:/usr/bin/xinit -e /home/brent/course/course

I have also removed all calls to gdm by removing them from the rc.x files

This does what I am after on my PC, starts in X, starts application "course"
but on the PC that actually does the measuring (which is 200 miles away), X
starts but the application does not leaving an X window with a usr prompt.
The application runs normally from the prompt.

Since I am having trouble with this method I wondered if there was a more
robust method. I also have to prevent the screensave mechanism from kicking
in from blanking and ideally, once I exit the application without shutting
down I would like to drop into a terminal.

Any pointers would be gratefully received.

Roger