ODS-5 is being introduced primarily to provide enhanced file
    sharing capabilities for users of Advanced Server for OpenVMS 7.2
    (formerly known as PATHWORKS for OpenVMS), as well as DCOM and
    JAVA applications.

    System managers must understand the impact of an ODS-5
    environment before enabling it for general users. It is essential
    that system managers perform the following steps before enabling
    ODS-5:

    o  Review all ODS-5 restrictions.

    o  Understand the support levels for different OpenVMS
       applications.

    o  Segregate applications that do not support ODS-5 or have not
       been tested with ODS-5 names or volumes.

                                   NOTE

       It is recommended that you enable ODS-5 disks in a
       homogeneous OpenVMS Version 7.2 (and later) Alpha cluster
       only.

1 - Mixed-Version Support

    Users on OpenVMS Alpha Version 7.2 (and later) systems can
    take advantage of Extended File Specifications capabilities. In
    contrast, systems running prior versions of OpenVMS cannot mount
    ODS-5 volumes, correctly handle extended file names, or even see
    extended file names.

    The following topics describe support on OpenVMS Version 7.2
    (and later) and on prior versions of OpenVMS in a mixed-version
    cluster.

    Users on OpenVMS Alpha Version 7.2 (and later) Systems

    Users on OpenVMS Alpha Version 7.2 and later systems can continue
    to access pre-Version 7.2 files and directories; for example,
    they can do all of the following:

    o  Create and access deep directory structures on ODS-2 volumes.

    o  Read a BACKUP saveset created on an earlier version of
       OpenVMS.

    o  Use DECnet to copy a file with an ODS-5 name to a file with an
       ODS-2 name on a system running an earlier version of OpenVMS.

    Users on pre-Version 7.2 Systems

    On mixed-version clusters, some restrictions exist. Users on a
    version of OpenVMS prior to Version 7.2:

    o  Cannot access any files on an ODS-5 volume. This is true
       regardless of whether the volume is connected physically on
       a CI or SCSI bus, or by an MSCP or QIO server.

    o  Cannot successfully create or restore an ODS-5 image saveset.
       However, these users can successfully restore ODS-2-compliant
       file names from an ODS-5 saveset.

2 - Mixed-Architecture Support

    All Extended File Specifications capabilities are available on
    OpenVMS Alpha Version 7.2 and later systems. Current ODS-2 volume
    and file management functions remain the same on both VAX and
    Alpha Version 7.2 (and later) systems; however, extended file
    naming and parsing are not available on VAX systems.

    The following topics describe support on OpenVMS VAX and Alpha
    systems in a mixed-architecture cluster.

    Limited Extended File Specifications Capabilities on VAX Systems

    In mixed-architecture OpenVMS Version 7.2 (and later) clusters,
    the following Extended File Specifications capabilities are
    available on OpenVMS Version 7.2 (and later) VAX systems:

    o  Ability to mount an ODS-5 volume

    o  Ability to write and manage ODS-2-compliant files on an ODS-5
       volume

    o  See only \pISO_LATIN\.??? or \pUNICODE\.??? when accessing an
       ODS-5 file specification

    BACKUP Limitations

    In a mixed architecture cluster, users cannot successfully create
    or restore an ODS-5 image saveset. However, these users can
    successfully restore ODS-2-compliant file names from an ODS-5
    saveset.

3 - Network Support

    Although Extended File Specifications is intended to provide
    enhanced file naming capabilities to Advanced Server for OpenVMS
    7.2 Version 7.2 for OpenVMS Version 7.2, network access with
    ODS-5 volumes and extended file names is currently being tested.
    The length of an extended file specification that can be passed
    over the network using DECnet is restricted to a maximum of 255
    bytes.

4 - Application Support

    OpenVMS applications should be evaluated and tested to determine
    whether they function correctly when Extended File Specifications
    is enabled. The OpenVMS System Manager's Manual, Volume 1:
    Essentials contains guidelines for evaluating applications, and
    the Guide to OpenVMS File Applications contains details about the
    technical aspects of Extended File Specifications that can affect
    the behavior of an application.

5 - User Support

    When you enable ODS-5 volumes on an OpenVMS cluster, you should
    make users aware of the following characteristics:

    o  Extended file names caooonot be used on ODS-2 volumes.

    o  Case is determined by the first instance of an extended file
       name.

    o  There are special rules for case preservation and case
       blindness when using extended file names.

    o  Some system utilities and DCL commands have a /STYLE qualifier
       to control the display of file names.

    o  Error messages can vary when different parse style are used.

    o  Extended file names are not visible from a VAX system.

    The OpenVMS System Manager's Manual, Volume 1: Essentials
    contains information for setting user's expectations of Extended
    File Specifications.