s the device containing the file.  The inode number and device
        number together uniquely identify the file, but the device number is
        not necessarily consistent across reboots or system crashes.

        @raise NotImplementedError: if the platform is Windows, since the
            device number would be 0 for all partitions on a Windows platform

        @return: a number representing the device
        @rtype: L{int}

        @since: 11.0
        )