HELPLIB.HLB  —  Ext File Specs, Overview  Impact
    The main goal of Extended File Specifications is to provide
    extended file naming capabilities, while also:

    o  Maintaining high reliability, scalability, and availability

    o  Maintaining the traditional (ODS-2) serial file interoperation
       capabilities

    o  Causing the least possible amount of change for layered
       products and applications

    However, once ODS-5 volumes are enabled, some of the new
    capabilities can potentially impact certain applications or
    layered products, as well as some areas of system management.

    The following guidelines and description of changes in the base
    operating system will help you determine the level of impact on
    your OpenVMS environment.

1  –  Support Guidelines

    Under Extended File Specifications, existing applications and
    layered products that are coded to documented interfaces, as well
    as most DCL command procedures, should continue to work without
    modification.

    However, applications that are coded to undocumented interfaces,
    or include any of the following, may need to be modified in order
    to function as expected on an ODS-5 volume:

    o  Internal knowledge of the file system, including knowledge
       of:

          The data layout on disk
          The contents of file headers
          The contents of directory files

    o  File parsing tailored to a particular on-disk structure.

    o  Assumptions about the syntax of file specifications, such as
       the placement of delimiters and legal characters.

    o  Assumptions about the case of file specifications. Mixed
       and lowercase file specifications will not be converted to
       uppercase, which can affect string matching operations.

    o  Assumptions that file specifications are identical between RMS
       and the file system.

                                   NOTE

       All unmodified XQP applications running on an OpenVMS
       VAX or Alpha system that access an ODS-5 volume will see
       pseudonames returned in place of Unicode or ISO Latin-
       1 names that are not ODS-2 compliant. This can cause
       applications to act in an unpredictable manner.

       Applications that specify or retrieve filenames with the
       XQP interface using ODS-5 disks must be modified in order to
       access files with extended names.

2  –  RMS Changes

    To support Extended File Specifications, the Record Management
    Services (RMS) have been enhanced to provide the following
    functions through existing interfaces:

    o  Support for a wider range of characters in a file name,
       extension, and directory

    o  Access to file specifications with extended characters

    o  Support for directory structures deeper than eight levels

    o  Access to file specifications longer than 255 bytes through
       the NAM block with some restrictions in functionality

    o  Access and complete specification of file specifications
       longer than 255 bytes by callers who are aware of the new
       naming characteristics through a new interface (NAML block)

2.1  –  Extended File Names

    With ODS-5 enabled, RMS can manipulate filenames and subdirectory
    specifications of up to 255 8-bit or 16-bit characters in length.
    RMS can handle a total path name 512 8-bit or 16-bit characters
    in length.

    Prior to OpenVMS Alpha Version 7.2, the NAM block interface could
    pass file specifications of up to 255 bytes each (including the
    resultant file specification). The following topics describe the
    changes that allow for passing longer file specifications and
    that provide compatibility with applications using the NAM block
    interface prior to this release.

2.2  –  Additional Character Sets

    With ODS-5, RMS supports access to files and directories whose
    names contain arbitrary 8-bit characters, except for the C0
    control set (hex 00 through 1F) and the following characters:

       Double quotation marks (")
       Asterisk (*)
       Backslash (\)
       Colon (:)
       Left and right angle brackets (< >)
       Slash (/)
       Question mark (?)
       Vertical bar (|)

    Note that this explicitly includes both the C1 character set (hex
    80-9F) as well as graphical and other characters between 9F and
    FF. This allows the entire ISO Latin-1 character set (with the
    7-bit character exclusions noted above) and any defined Unicode
    character.

2.3  –  Deeply Nested Directories

    Under Extended File Specifications on Alpha, RMS 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. The deep nesting of directories is also
    supported on ODS-2 disks.

3  –  File System (XQP) Changes

    The following Files-11 Extended QIO Processor (XQP) file system
    enhancements are offered under Extended File Specifications
    through the $QIO interface. Note that in some cases, XQP file
    format rules may differ from those that apply to other system
    services that accept file names, such as those provided by RMS.

    o  The current restrictions on the format and content of file
       names have been modified, specifically:

       -  The 39.39 file name length restriction was removed to allow
          longer file names, up to 236 8-bit characters or 117 16-bit
          characters

       -  The use of characters from the ISO Latin-1 multinational
          character set is supported in file specifications

       -  Support for the entry and storage of file and directory
          specifications in Unicode.

4  –  DCL Commands and Utilities

    In DCL commands, you can select either of the following styles
    for parsing file specifications:

    o  Traditional filenames are allowed on both ODS-2 and ODS-5
       volumes.

    o  Extended filenames are allowed on ODS-5 but not on ODS-2
       volumes.

    Some OpenVMS commands and utilities have new qualifiers to
    control the interpretation and display of file specifications.

                                   NOTE

       DCL lexical functions use the DEC-Multinational character
       set, which is different from the ISOLatin-1 character set
       used for file names on an ODS-5 disk. This can lead to
       unexpected results if, for example, you use the DCL function
       F$EDIT to upcase a filename.

    Some DCL commands and OpenVMS utilities have been specifically
    modified to take advantage of all the features of extended file
    names. These utilities and commands accept and handle extended
    file specifications without error and without modifying their
    expected case.

    Other DCL commands and OpenVMS utilities have had little or
    no modification to take advantage of extended file names.
    These utilities and commands are expected to handle most of
    the attributes of extended file specifications (such as new
    characters and deep directory structures) correctly.

    Extended File Specifications Support fully defines the different
    levels of support for extended file names provided by DCL
    commands and OpenVMS utilities in OpenVMS Version 7.2 and later.

    The following DCL commands and OpenVMS utilities provide full
    support for extended file names:

       ANALYZE /AUDIT
       ANALYZE /DISK
       ANALYZE /RMS
       BACKUP
       CONVERT
       CONVERT /RECLAIM
       COPY
       CREATE /DIRECTORY
       DELETE
       DIRECTORY
       DUMP
       EDIT /ACL
       EXCHANGE /NETWORK
       FDL
       PURGE
       RECOVER/RMS
       RENAME
       SEARCH
       SET SECURITY
       SYSMAN
       TYPE

 The following table lists the new features in DCL to support
 Extended File Specifications.

    DCL Command            New Features

    COPY                   Added new qualifier, /STYLE, with new
                           keywords, EXPANDED and CONDENSED
    DELETE                 Added new qualifier, /STYLE, with new
                           keywords, EXPANDED and CONDENSED
    DIRECTORY              Added the following items:

                           o  Qualifier, /STYLE, with new keywords,
                              EXPANDED and CONDENSED

                           o  Display item to /FULL to display Client
                              Attributes

    DUMP                   Added the following items:

                           o  Display item to /DIRECTORY to display
                              Name type attribute

                           o  Display item to /HEADER to display new
                              attributes

                           o  Qualifier, /STYLE, with new keywords,
                              EXPANDED and CONDENSED

    EXCHANGE NETWORK       Added new qualifier, /STYLE, with new
                           keywords, EXPANDED and CONDENSED
    F$FILE_ATTRIBUTES      Added new item codes: FILE_LENGTH_HINT,
    Lexical                VERLIMIT, DIRECTORY
    F$GETDVI Lexical       Added new type to the ACPTYPE item code.
    F$GETJPI Lexical       Added new item codes: PARSE_STYLE_PERM and
                           PARSE_STYLE_IMAGE
    INITIALIZE             Added a new qualifier: /STRUCTURE=5
                           device-name[:] volume-label
    PRINT                  Added new qualifier, /STYLE, with new
                           keywords, EXPANDED and CONDENSED
    PURGE                  Added new qualifier, /STYLE, with new
                           keywords, EXPANDED and CONDENSED
    RENAME                 Added new qualifier, /STYLE, with new
                           keywords, EXPANDED and CONDENSED
    SEARCH                 Added new qualifier, /STYLE, with new
                           keywords, EXPANDED and CONDENSED
    SET ACL                Added new qualifier, /STYLE, with new
                           keywords, EXPANDED and CONDENSED
    SET DEFAULT            Updated the following items:

                           o  Modified the directory-spec parameter
                              to accept ODS-5-compliant file
                              specifications.

    SET DIRECTORY          Added new qualifier, /STYLE, with new
                           keywords, EXPANDED and CONDENSED
    SET FILE               Added new qualifier, /STYLE, with new
                           keywords, EXPANDED and CONDENSED
    SET PROCESS            Added a new qualifier: /PARSE_
                           STYLE=(keyword), where keywords are
                           TRADITIONAL and EXTENDED.
    SET SECURITY           Added new qualifier, /STYLE, with new
                           keywords, EXPANDED and CONDENSED
    SET VOLUME             Added a new qualifier: /STRUCTURE_LEVEL=5
    SHOW DEVICE/FULL       Updated the display information to show
                           the disk structure level.
    SUBMIT                 Added new qualifier, /STYLE, with new
                           keywords, EXPANDED and CONDENSED
    TYPE                   Added new qualifier, /STYLE, with new
                           keywords, EXPANDED and CONDENSED

    For detailed information about the enhancements made to the
    OpenVMS operating system and utilities in support of Extended
    File Specifications, see the OpenVMS DCL Dictionary: A-M, the
    OpenVMS DCL Dictionary: N-Z, and the OpenVMS Utility Routines
    Manual.

5  –  DCL Command Parameters

    Command procedures that use file names as parameters can produce
    different results in an ODS-5 environment.

    See DCL Command Parameters for more information about using ODS-5
    style names in DCL command procedures.

6  –  System Services Changes

    The following system services have been modified or added to
    support Extended File Specifications:

    o  New services:

       -  $SET_PROCESS_PROPERTIESW

       -  $CVT_FILENAME

    o  Changed services:

       -  $CREPRC

       -  $GETJPI

       -  $SETDDIR
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