Richard J.”Derf” Diefenderfer, age 73, of Halethorpe, MD passed away on April 18, 2016 following a long battle with COPD. Born on Oct. 25, 1942 in Hazleton, PA, he was the son of the late John B. and Dorothy E. Diefenderfer (nee Dorneman). He graduated from Penn State in 1963. He worked as a Test Director and Program Manager for the National Security Agency for 36 yrs. and as a Test Engineer with Engineering Solutions, Inc. for 8 yrs. Following his retirement from NSA. He was a huge sports fan and followed the Orioles, Ravens & Terps teams. Derf also loved playing pinochle and played both online and at live tournaments around the country.