def parse_main_folder_name(main_folder_name):
    """
    parse the name of the main folder here, and return the follwing parts
    date, string
    raft_geometry, string
    thin_film_prop, string
    magnet_field_prop, string
    comments, string
    """
    parts = main_folder_name.split('_')

    date = parts[0]
    raft_geometry = parts[1]
    thin_film_prop = parts[2]
    magnet_field_prop = parts[3]

    if len(parts) > 4:
        comments = parts[4]
    else:
        comments = 'none'

    return date, raft_geometry, thin_film_prop, magnet_field_prop, comments