bas7advr.hlp (Topic list)
SCREEN Modes 7, 8, and 9
                                                 Contents  Index  Back
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                    EGA or VGA Adapters
SCREEN 7: 320 x 200 graphics
    ■ 40 x 25 text format, character box size 8 x 8
    ■ 32K page size, pages 0-1 (64K adapter memory), 0-3 (128K), or 0-7
      (256K)
    ■ Assignment of 16 colors to any of 16 color attributes
SCREEN 8: 640 x 200 graphics
    ■ 80 x 25 text format, 8 x 8 character box
    ■ 64K page size, pages 0 (64K adapter memory), 0-1 (128K), or 0-3
      (256K)
    ■ Assignment of 16 colors to any of 16 color 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 0 (64K adapter memory);
      128K page size, pages 0 (128K adapter memory) or 0-1 (256K)
    ■ 16 colors assigned to four color attributes (64K adapter memory), or
      64 colors assigned to 16 color attributes (more than 64K adapter
      memory)