def create_system_id(os_string, architecture):
    """
    Create a system-ID by joining the OS-String and the architecture with a hyphen.

    Args:
        os_string (str):
            The Operating system string.
        architecture (str):
            The Architecture string.

    Returns:
        The System-ID string.

    """
    system_id_format = '{os_string} {architecture}'
    return system_id_format.format(os_string=os_string.replace('_', ' '),
                                   architecture=architecture)