I want to build a gadget with PC-boards like raspberry and Linux(or Windows) OS. And when user turns on the gadget sees my company name, and directly goes to my program and couldn't exit from that.something like ATM machines. How can I do that? What is this topic name and where can I find sources and guides?
You can hard-code your user-space process to run after bootup by updating the init script. You can run it as a daemon process and block all signals to it by the user. You can further disable other services and application processes like login process if you want the application to be accessed by everyone.