VMS Help Ext File Specs, VAX and ODS-5  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    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.

    Limited Capabilities on VAX Systems
    In mixed-architecture OpenVMS Version 7.2 and later clusters,
    OpenVMS Version 7.2 and later VAX systems are limited to the
    following Extended File Specifications functionality:

    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 pseudonames (\pISO_LATIN\.??? or \pUNICODE\.???) when
       accessing ODS-5 file specifications

    BACKUP Limitations
    From a VAX system, 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.