One field of the VgaSavePtr2Rec points to a VgaDccRec.  This structure is
 initialized by the VGA video system BIOS to point to a table in ROM.

 Information in this structure identifies valid combinations of video
 subsystems which are supported by your VGA BIOS.  For instance, your VGA
 BIOS may support both an EGA and a VGA while mine won't.

 See INT 10H 1aH for info on querying valid combinations and switching back
 and forth between monitors.

  Offset Size Contents
   +0      1  bEntries     entries in wCombos
   +1      1  bVersion     DCC table version number
   +2      1  bMaxTypeCode maximum display type code
   +3      1  res          (reserved)
   +4      2  wCombos      a variable-length list of byte-pairs identifying
                           valid display combinations.  For instance, 0108H
                           means supports a monochrome adapter and a color
                           VGA adapter.  See INT 10H 1aH for codes.
      4+(2*n)              size of a VgaDccRec structure

See Also: VGA Data Areas
          VGA I/O Ports