Int 15 Fn 1024  - Topview - "getbuf" - Get Virtual Screen Info             [Q]

   AX = 1024h
   BX = segment of object handle for window
         (0 = use default)

Return: ES:DI -> virtual screen
   CX = size of virtual screen in bytes
   DL = 00h text screen
        01h graphics screen

See Also: INT 10/AH=FEh,INT 21/AH=2Bh/CX=4445h