VMS Help BACKUP Command, Qualifiers, /IMAGE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Command Qualifier

    Directs BACKUP to process an entire volume or volume set.
    Using this qualifier produces a functionally equivalent
    copy of the original volume or volume set. To use the /IMAGE
    command qualifier, you need write access to both the index file
    (INDEXF.SYS) and the bit map file (BITMAP.SYS), or the input
    medium must be write-locked.

    In save and copy operations, you cannot use input file-selection
    qualifiers with the /IMAGE command qualifier because BACKUP saves
    or copies all files on the input disk volumes.

    In restore and copy operations, every file is restored or copied.

    The output volume must be mounted using the /FOREIGN qualifier.
    The new volume is a functionally equivalent copy of the input
    volume; however, the file placement will change.

    An image restore or copy operation initializes the output volume
    or volume set. The initialization data comes from the save-
    volume summary record of the input volume, unless the command
    qualifier /NOINITIALIZE directs BACKUP to initialize the output
    volume using volume initialization data that already exists on
    the output volume.

    A BACKUP operation to mixed tape and disk save sets, as shown in
    the following command, is unsupported:

    $ BACKUP SYS$DISK:/IMAGE DKA0:FUN,MKA0:/SAVE/REW

    Specifying the /IMAGE qualifier without also specifying /NOALIAS
    can result in incomplete disk or file restoration operations.
    Therefore, Compaq strongly recommends that you specify /NOALIAS
    with /IMAGE when performing image mode backup operations.

                                   NOTE

       If you do not specify /NOALIAS, the /ALIAS qualifier is
       activated by default.

    Beginning in OpenVMS Version 7.2, when you use the BACKUP/IMAGE
    command to restore or copy a volume, the BACKUP utility preserves
    the cluster factor. Note that copying a volume with a bitmap
    smaller than 255 blocks to a significantly larger disk might
    result in a bitmap larger than 255 blocks on the destination
    disk. (You cannot mount such a disk on an OpenVMS Version 7.1 and
    earlier system.)