peterl@ibmpcug.co.uk (Peter Leaback) (01/08/91)
> Does someone know why the maximum ScreenSize is limited to 480K? It >means that one cannot double-buffer bigger than 240K screens (mode >21/24/28). The MEMC can only DMA out of the bottom half meg of physical ram, so a 480K limit is to allow for cursor and sound DMA as well. It is a great shame that the MEMC has this limit, and as you say, one can't double-buffer large screens. What would have been nice would be if the address generators could take logical addresses, so one could play around with the memory map. But this would mean extra logic. Regards,Pete Leaback. . -- Automatic Disclaimer: The views expressed above are those of the author alone and may not represent the views of the IBM PC User Group. --