can i put this in m book? --- forsyth the way to get good portability is to have clear, well-designed interfaces that abstract away from hardware peculiarities, and map those to the hardware (rather than, say, reflecting in the interfaces the union of every peculiarity of all hardware known to you at the time).
some of the hard bits about kernel development are: - getting accurate documentation for the processor, devices, existing bootstrap, etc. - getting anything loaded into the wretched machine at all - deciding how your kernel should look, what it should do, how it should change - working out a good infrastructure for networks, devices coming and going, power, etc. - finding time and/or money to do any of it
