Don,
You can DMA into any memory that resides within the 16Meg range that the
Amiga hardware supports. (limited by the 24 address lines on the Amiga buss)
(BTW, this also assumes that the hardware designer built the memory system to
allow DMA, all Zorro boards should allow it, but most of the memory on
co-processor boards fail to)
The 2620's 32 bit memory autoconfigs into the normal 8Meg expansion area,
which allows it to be DMA'd to. Having the memory outside the normal memory map
really does nothing except make the designers job easier. The 2620 is perfectly
capable of remapping the ROM code int 32 bit RAM, it only requires that you
allocate it from the system first. (the memory you're going to remap, that is)
I certainly not the final word on the subject, so I would advise getting
those reference materials as well. Ariel suggested a few good ones in another
message.