EGA and VGA Adapter SCREEN Modes
SCREEN 7: 320 x 200 graphics
  - 40 x 25 text format, character box size 8 x 8
  - 32K page size, page ranges are 0-1 (64K), 0-3 (128K), or 0-7 (256K)
  - Assignment of 16 colors to any of 16 attributes
SCREEN 8: 640 x 200 graphics
  - 80 x 25 text format, 8 x 8 character box
  - 64K page size, page ranges are 0 (64K), 0-1 (128K), or 0-3 (246K)
  - Assignment of 16 colors to any of 16 attributes
SCREEN 9: 640 x 350 graphics
  - 80 x 25 or 80 x 43 text format, 8 x 14 or 8 x 8 character box size
  - 64K page size, page range is 0 (64K);
    128K page size, page range is 0 (128K) or 0-1 (256K)
  - 16 colors assigned to 4 attributes (64K adapter memory), or
    64 colors assigned to 16 attributes (more than 64K adapter memory)