Buildroot: Start a program before/instead of linux login and after X.org has started

Question

I would like to create a very small linux that boots up and loads a program into execution. I am using Buildroot in this endeavor. It would be nice if I could install the X.org without any desktop management environment (like Gnome or the many others) and just run a GUI app that would display various functionalities. I'd like to use it for accessing HDDs and USB sticks, to copy data from a partition to another.. simple tasks.. like this one.

I've started by following this tutorial and I will advance to this one this but first I want to see how I could start a program at boot time, before any login and shutdown the OS from that program or when that program exists (first No GUI program). Until now I have manage to follow the first tutorial successfully.

But even more importantly it would be the question: how could I put together the Linux image and an app of my own so that if I create a bootable media (CD/USB stick) the linux would find it and run it?

The next question would be how would I start a GUI app just after the X has started.

Answer 1

Why do you need X.org?

I'd try Qt first. It can run without X.org via frame buffer. See this link: http://qt-project.org/doc/qt-4.8/qt-embedded-linux.html

Another alternative were to use http://directfb.de/

To start an application you just need to create a startup script in /etc/init.d/