I am considering ordering one or more Smith Co. censuses from SK Publications (http://www.skcensus.com/census/tn/smith.html). I can get 5 cd's to cover 1820-1910 (except for 1870) for a total cost of $100, or I can get 1 dvd to cover the same time period for $30. Will both types work on a computer that has dvd capability? Is there a benefit to the cd's that I haven't thought of? Why such a cost difference? Thanks for your help! Jenny Calvin