I doubt x64 would be less horrific. As for ARM, there is Cambridge's Baking Pi course http://www.cl.cam.ac.uk/projects/raspberrypi/tutorials/os/ http://www.cl.c

I doubt x64 would be less horrific. As for ARM, there is Cambridge's Baking Pi course http://www.cl.cam.ac.uk/projects/raspberrypi/tutorials/os/ http://www.cl.cam.ac.uk/projects/raspberrypi/tutorials/os/, which has you develop an "Operating System" for the Raspberry Pi. Although, from looking at it, it seems more like an embedded systems course than an OS course. It talks about controlling hardware like LEDs, monitor, and keyboard, but it doesn't talk about stuff that full-fledged operating systems have, like scheduling of userspace processes, memory mapping, filesystems, etc.