Incremental backup operation

    Depending on the type of save operation you are performing, the
    incremental option does the following:

    Save Type   Description
    ---------   -----------
    Volume      The incremental type of backup saves the new or changed
                files on the volume since the last baseline or incremental
                backup operation on the same set of files.

    Selected    The incremental type of backup saves the new or changed
    Files       files that are specified since the last baseline or
                incremental backup operation on the same set of files.