To support POSIX-compliant file timestamps on ODS-5 disks, file
    attributes have been extended to include the following three
    access dates:

    o  The last access date (XAB$Q_ACC)

    o  The last attribute modification date (XAB$Q_ATT)

    o  The last data modification date (XAB$Q_MOD)

    The XABITM SENSEMODE interface can be used with the following
    item codes on $OPEN or $DISPLAY operations to sense each of these
    three access dates:

    o  XAB$_ACCDATE

    o  XAB$_ATTDATE

    o  XAB$_MODDATE

    Sensing these dates requires that access date support be
    enabled on the ODS-5 volume. (See the DCL SET VOLUME/VOLUME_
    CHARACTERISTICS command in the OpenVMS DCL Dictionary: N-Z.)

    A SETMODE can be used with a $CLOSE operation with any of these
    item codes to update these dates regardless of the volume
    setting. A user may inhibit the update of the access dates by
    using the XAB$_NORECORD XABITM.

    Each of these item codes requires a quadword buffer.

    If a SENSEMODE using any of these item codes is requested for a
    non-ODS-5 file, a zero is returned. A SETMODE using any of these
    item codes for a non-ODS-5 file will be ignored.

    These items are ignored for DECnet operations. If a SENSEMODE
    is attempted for any of these items, the user buffer is left
    unchanged.