From Spectrum Next Development
"Please note that NextOS moves Layer 2 and its shadow version 2 pages down. Therefore, layer 2, after NextOS boots, is mapped to pages 18-23, and the shadow layer 2 is mapped to pages 24-29."
Shouldn't this be 20-23,24-29? And I would say that's 2 pages up (numerically), but I now understand the "down" here means down toward end of physical address space. I think the whole page should be rather rewritten with terms start/end and similar, instead of down/bottom (I have often seen memory maps being drawn with address 0 at bottom, and growing "up" toward end of address space).