Ref
buildroot
http://free-electrons.com/doc/training/buildroot/buildroot-slides.pdf
qemrdux-player
https://github.com/mpolakovic/qemrdux-player
Mdev
https://git.busybox.net/busybox/plain/docs/mdev.txt https://wiki.gentoo.org/wiki/Mdev/Automount_USB http://free-electrons.com/doc/mdev-lab.pdf http://free-electrons.com/doc/udev.pdf
WiringPi
http://wiringpi.com/ https://www.raspberrypi.org/forums/viewtopic.php?f=33&t=93613