Some preliminary results from building a archive of rpm deltas from the FC3 updates directory which are very encouraging. I've been running it overnight (only a 750MHz P3) and it has built about 700 deltas so far. Mean size of delta comparted to whole RPM: 13.5% About half of the deltas are under 5% of whole RPM. One in four are under 2% of the whole RPM. I will post more detailed stats when I've completed this experiment. Joe.