Creates a backup file of the database after-image journal (.aij)
    file or files.

    Oracle Rdb supports two types of after-image journaling
    mechanisms: one that employs a single, extensible .aij file and
    another that employs multiple, fixed-size .aij files. The type of
    journaling mechanism being used at the time the backup operation
    starts can affect how you should specify the backup command.
    Further information on how these two journaling mechanisms affect
    the backup operation appears in the Description help entry under
    this command.

    The backup .aij file is an actual, usable .aij file that can
    be applied to the appropriate Oracle Rdb database in a recovery
    operation.

    The RMU Backup After_Journal command can be used while users are
    attached to the database.