Controls the Undo/Redo feature of the input module. On some installations, it may be useful to disable the Undo/Redo feature of the input module. With Undo/Redo enabled, CAESAR II can process a job approximately one-half the size of that which can be processed when Undo/Redo is disabled (for similar memory settings). Likewise, with Undo/Redo enabled, the input module speed may be reduced.