Int 21 Fn 4409  - Dos 3.1+ - Ioctl - Check If Block Device Remote          [D]

   AX = 4409h
   BL = drive number (00h = default, 01h = A:, etc)

Return: CF clear if successful
       DX = device attribute word
       bit 15: drive is SUBSTituted
       bit 13: (DR DOS 3.41/5.0 local drives only) always set
           media ID needed
       bit 12: drive is remote
       bit  9: direct I/O not allowed
   CF set on error
       AX = error code (01h,0Fh) (see #1366 at AH=59h/BX=0000h)

Notes: on local drives, DX bits not listed above are the attribute word from
     the device driver header (see #1332 at AH=52h); for remote drives,
     the other bits appear to be undefined for MS-DOS versions prior to
     5.0 (they are all cleared in DOS 5+)
   checking whether DX=0800h on return appears to be a fairly reliable
     method for detecting Microsoft's RAMDRIVE, though not for other
     ramdisks (there appears to be no simple yet foolproof method for
     detecting ramdisks, although the presence of only a single copy of
     the FAT and only a single head on non-removable devices is a fairly
     good indicator); for Windows95, RAMDRIVE returns DX=4800h
   this function was not supported by Digital Research's DOS-Plus

See Also: AX=4400h,AX=4408h,AX=440Ah,INT 2F/AX=122Bh