Hello   I am writing a Linux applications that should have the following characteristics :  - start as a background process at system start-up (before user log in) 
- no taskbar element - have a GUI (launched by user) for changing some parameters 
- possibility to show some messages to user (alarms, errors)  I thought of building a shared library (embeded) with an infinite loop that does the process, and another application that contains the GUI and implement some kind of communication between them. How should I start the process at start-up?  I am pretty new to linux, so any suggestion will be probably helpful.  Thanks Cristian