Function 4409h (68-9)    IOCTL: Is Logical Device Remote?           ≥ DOS 3.1

    Reports whether a block device is associated with a network directory.

       On entry:      AH         44h
                      AL         09h
                      BL         Drive number (0=default, 1=A, etc.)

       Returns:       DX         Bit 12  1           If device is local
                                 Bit 12  0           If device is remote

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    This subfunction (DOS 3.1 and later only) allows you to determine
    whether a block device (specified in BL with default=0, A=1, etc.) is
    associated with a network directory. For local devices, DX returns the
    attribute word from the device header; for remote devices, DX returns
    with bit 12 set.