How to create bootable GUI programs?

*"for Retro computing purposes only"*

Some programs are directly bootable and have a nice GUI

e.g. Acronis OS Selector and Disk Director (screenshot)

How can they run wihtout underlying OS? Can this be acheived by using a minimal Linux distribution?

goal: the program should run such that it appears independent of the os (e.g you dont have to launch it from the os cmd or desktop)

also the OS should not have increase the size of the program a bit too much

Also I wonder if Qt GUI's can run like this...

The story behind a comprehensive GUI + bootable program is somewhat like this:

• Develop the program in a linux GUI toolkit
• On boot, load a linux kernel (without any desktop environment)
• Hand over the control to the program GUI

more info: Bootable Qt-Linux Application