The following topics describe the deeper directory structures and
 extended naming syntax available with Extended File Specifications.
 It is now possible to go beyond the eight levels of directories
 previously supported in OpenVMS.
    See also the OpenVMS User's Manual and the Guide to OpenVMS File
    Applications for more information about directory specifications
    in Extended File Specifications.

1  –  Deep Directory Structures

    OpenVMS 7.2 and later supports deep nesting of up to 255
    directories with the restriction that the total directory
    specification must be no longer than 512 8-bit or 16-bit
    characters.

    For example, a user can create the following directories on an
    ODS-2 or ODS-5 volume:

    $ CREATE/DIRECTORY [a.b.c.d.e.f.g.h.i.j.k.l.m]

    A user can create the following directory with a long name on an
    ODS-5 volume:

    $ CREATE/DIRECTORY -
    [.AVeryLongDirectoryNameWhichHasNothingToDoWithAnythingInParticular]

2  –  Directory Naming Syntax

    When using Extended File Specifications, directory names conform
    to most of the same conventions as file names when using the
    ISO Latin-1 character set. Periods and special characters may
    be present in the directory name, but they must be preceded by a
    circumflex (^) in order to be recognized as literal characters,
    as shown in the following table:

    CREATE/DIRECTORY. . .       Result

    [Hi^&Bye]                   Hi^&Bye.DIR;1
    [Lots^.Of^.Periods^.In^.ThisLots^.Of^.Periods^.In^.This^
                                .Name.DIR;1

3  –  Directory ID and File ID Abbreviation

    Under some circumstances, a full file specification may contain
    more characters than the 255 bytes allowed by unmodified
    applications. If a file specification that such an application
    needs exceeds 255 bytes in length, RMS generates a shorter
    file specification by abbreviating the directory to a DID
    abbreviation, and if necessary, the filename to a FID
    abbreviation.

    When the file specification is too long, RMS first attempts to
    generate a shorter directory specification by identifying the
    directory with its directory ID. This shorter specification is
    referred to as a DID abbreviation.

    TEST$ODS5:[5953,9,0]Alghero.TXT;1

    Note that this form of the directory name must have three numbers
    and two commas to avoid ambiguity with UIC format directory
    names. With the DIRECTORY command you can view the shorter
    DID abbreviation version as well as the full version of a file
    specification.