如何判断光驱是CD还是DVD

// 0: Unknown
// FILE_DEVICE_CD_ROM: CD-ROM
// FILE_DEVICE_DVD   : DVD-ROM
function GetCDType(Drive: Char): DEVICE_TYPE;
const Size = 2048;
var
  hDrive: THandle;
  dwBytesReturned : DWORD;
  bMediaTypes     : array[0..Size-1] of Byte;
  rMediaTypes     : TGetMediaTypes absolute bMediaTypes;
begin
  Result := 0;
  hDrive := CreateFile(PChar('\\.\' + Drive + ':'), GENERIC_READ,
    FILE_SHARE_READ, nil, OPEN_EXISTING, 0, 0);
  if hDrive = INVALID_HANDLE_VALUE then Exit;

  if DeviceIoControl( hDrive, IOCTL_STORAGE_GET_MEDIA_TYPES_EX, nil, 0,
     @bMediaTypes, Size, dwBytesReturned, nil ) then
    with rMediaTypes do
      if MediaInfoCount > 0 then Result := DeviceType;
        
  CloseHandle(hDrive);
end;

其中DEVICE_TYPE/TGetMediaTypes都定义在 IoCtl.pas 里

其实在 IoCtl.pas 里有个方法 GetMediaType，返回的是 STORAGE_MEDIA_TYPE，值有N多，比如
  RemovableMedia     = 11; // Removable media other than floppy
  FixedMedia         = 12; // Fixed hard disk media
  ...
  CD_ROM             = 51; // Opt_Disk - CD
  CD_R               = 52; // Opt_Disk - CD-Recordable (Write Once)
  CD_RW              = 53; // Opt_Disk - CD-Rewriteable
  DVD_ROM            = 54; // Opt_Disk - DVD-ROM
  DVD_R              = 55; // Opt_Disk - DVD-Recordable (Write Once)
  DVD_RW             = 56; // Opt_Disk - DVD-Rewriteable
应该可以更详细的确定驱动器类型，但是我测试下来发现我机器的DVD-RW被认成CD_ROM
不知道什么问题，有时间再研究下