With support for extended characters in filenames for ODS-5,
    a name such as NAME.EXT can be interpreted as NAME.EXT.DIR.
    Determining if directory [.name^.ext] exists adds overhead to
    UNIX name translation when support for extended character support
    in UNIX filenames is enabled.

    Enabling the DECC$EFS_NO_DOTS_IN_DIRNAME feature logical
    suppresses the interpretation of a filename containing dots as
    a directory name. With this logical enabled, NAME.EXT is assumed
    to be a filename; no check is made for directory [.name^.ext].