If you save maps in postscript format, they can use large amounts of space. DD warns you about this if you select the postscript output option with more than 10 maps, but does not do so otherwise, nor does it attempt to find out whether enough space exists to write them out. If you want to check how much disk space a set of maps will take, simply choose the ``Change Map File Output Style'' option on the Maps ``Save'' menu, and reselect postscript output.