[net.micro.6809] 9K Coco Graphics Mode??

knudsen@ihnss.UUCP (12/06/83)

I saw a reference to an "undocumented 9K graphics mode" for the Coco.
What could this be?  The SAM/VDG (6883/6847) combo uses at most 6K
for PMODEs 3 & 4 or Semigraphics-24 modes.  How could the SAM pull out
50% more data per frame, and what could the VDG do with it?
Might this be a use for the fully undocumented (even by Motorola)
"DMA mode" in the SAM?  Doesn't that mode just keep fetching bytes
during the screen borders, when VDG ignores it?
	The reference was in The Rainbow, this Dec, in the "reviews of
reviews" page.  The maker of some color organ program claimed to have
the 9K mode(s).  Any speculations?  mike k