All governments gather information about their citizens. The Nazi regime, however, used such information to track political opponents, enforce racial policies, and, ultimately, implement mass murder. As early as 1934, various government bureaus began to compile card catalogs identifying political and racial enemies of the regime, such as Freemasons, Jews, Sinti and Roma (Gypsies), and "genetically diseased" persons. The 1939 census became the basis for a national register of Jews. That year, German census forms for the first time included explicitly racial categories. Jews were identified not only by religious affiliation, but by race as well. Within three years, the completed national register of Jews and some Jewish Mischlinge ("mixed breeds") was to become one of the sources for Nazi deportation lists. Most of those deported perished in the Holocaust.
During the 1930s and 1940s, Hollerith machines were the best data processing devices available. The Nazi regime employed thousands of people in 1933 to 1939 to record national census data onto Hollerith punch cards. The SS used the Hollerith machines during the war to monitor the large numbers of prisoners shipped in and out of concentration camps. The machines were manufactured by DEHOMAG-Deutsche Hollerith Maschinen Gesellschaft or German Hollerith Machine Company, a subsidiary of IBM since 1922.United States Holocaust Memorial Museum