Totally off topic, but I figure there are some experts here that
I have not found on pc newsgroups.
        I'm working with Data Light's ROM-DOS, putting a BIOS extension
at 0 d000:0 that refers to data at 8 0000:0.  My hardware seems to be
working with the stuff in conventional memory, but neither view-xm nor
rom-dos can find the stuff in extended memory.
        In a PAL (16R8), I'm generating chip selects to drive the EPROM
and a 74hc245 bus transceiver based on latching LA23..LA20 and A19..A16
on the negative edge of ALE.  For the chip enable to go true, AEN also
has to be low (not in a DMA cycle).
        Anyone have more experience with the ISA bus?  I've got a logic
analyzer coming in this morning to dig into it.  One question that
remains to me, however, is how does the motherboard memory map decoding
know where to go to find memory?  Stuff in extended memory COULD be in
SIMMS, or could be on the ISA bus.  Does it go looking during POST and
map stuff accordingly?

THANKS!

Harold