DOS Fn 4400H and 4401H use this for values passed in DX.  The bit flags
have different meanings, depending upon bit 7 (device or file).

Note: The upper 8 bits are the same as those in the Device Attribute
for the device.

IoctlDevInfoRec     layout when describing a device
1 1 1 1 1 1
 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 
 1     0   0 0 0 1 e b f c n o i 
                                  bit  mask
                                  0: 0001H Console Input device
                                  1: 0002H Console Output device
                                  2: 0004H Null device
                                  3: 0008H Clock device
                                  4: 0010H special device; fast output
                                  5: 0020H binary mode; 0=ASCII
                                  6: 0040H not EOF; 0=EOF on input
                                  7: 0080H 1=device
                                 11: 0800H supports device open  DvRq 0DH
                                           and device close      DvRq 0EH
                                 13: 2000H spts output-till-busy DvRq 10H
                                 14: 4000H supports IOCTL Read   DvRq 03H
                                           and IOCTL Write       DvRq 0CH
                                 15: 8000H 0=block device; 1=char device

IoctlFileInfoRec     layout when describing a file
1 1 1 1 1 1
 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 
 0     0   0 0 0 0    drive ID   
                                  bit  mask
                                 0-5: 003fH drive ID (0=A, 1=B, etc.)
                                   6: 0040H not EOF; 0=EOF on input
                                   7: 0080H 0=file
                                  11: 0800H supports device open  DvRq 0DH
                                            and device close      DvRq 0EH
                                            and Removable Media   DvRq 0FH
                                  13: 2000H 0=Needs FAT with BPB  DvRq 02H
                                  14: 4000H supports IOCTL Read   DvRq 03H
                                            and IOCTL Write       DvRq 0CH
                                 15: 8000H 0=block device; 1=char device

See Also: fn 4400H (IOCTL query device/file flags)
fn 4401H (IOCTL set device/file flags)
- -

IOCTL Device or File Info