OpenVMS Alpha Version 7.2 and later implements On-Disk Structure
    Level 5 (ODS-5). This structure provides the basis for creating
    and storing files with extended file names. You can choose
    whether or not to enable ODS-5 volumes on your OpenVMS Alpha
    systems.

    The ODS-5 volume structure allows the following features:

    o  Long file names

    o  More characters legal within file names

    o  Preservation of case within file names