Thanks Joonas. It is going to run the C++ program on NXP i.MX-6ULZ ARMv7, the application is running on about 5MB RAM, I think RAM looks fine. The boost and other C++ system libraries about 6 MB, the program self is not too large, about 2 MB libraries and 500 KB binary application, I need to know the OS Debian Stretch armhf size. Thank you