File name format
    A file name is a unique name for a file.  It can identify the device,
    the directory name, the file name, the file type, and the version
    number under which the file is stored.  OpenVMS uses the following
    format for a file name:
       Device:[Directory]Filename.Type;Version
    For example:
       USER1:[SMITH]LOGIN.COM;125
    The components of the file specification are as follows:
    Device      The name of a disk or tape device on which a file is
                stored, such as DUA0:, MUA0:, and so on.  Physical disk
                or tape devices often have logical names associated with
                them, such as USER$DISK.  See also "Physical and logical
                device names" in the "Concepts ..." help topic.
    Directory   The directory in which a file is listed.  The directory
                name can include subdirectories, begins with a left
                square bracket ([) or a left angle bracket (<), and ends
                with a corresponding right square bracket (]) or right
                angle bracket (>).
    File name   A name for a file.  The file name can have up to 39
                characters.
    File type   A name for a type of file.  The file type follows a period
                delimiter and can have up to 39 characters.  By convention,
                the file type identifies a generic class of file, such as
                .TXT for a text file.
    Version     The version number of a file is preceded by a semicolon,
                for example, ;22.
    For more information about specifying files, see the following
    topics:
       "Using wildcards for specifying files" in the "Tasks ..." help topic.
       "File name wildcards" in the "Concepts ..." help topic.