and 2B; [0019]FIG. 4 shows a schematic block diagram of one half of the system of FIG. 2A highlighting that the replication engine is a separate and distinct entity from the application engine; [0020]FIGS. 5A, 5B, 6A, 6B, and 7A, 7B each taken together, are a schematic block diagrams of the system of FIGS. 2A and 2B, further defining additional paths (5A, 5B and 6A, 6B only) and back channels (7A