After going through some of the documentation available to me I'm still unsure about how a program can discover the upper and lower limits of system memory. On Pegasos, Efika and Mac, is system memory in a contiguous range? Or is it still broken up as on 68k Amigas?

While I'm asking technical questions, I'm also lacking information on the structure of segments - as in LoadSeg() segments. Is it still the case that NewLoadSeg() and InternalLoadSeg() only have tags as a yet to be implemented feature?