Nazi Germany announces the Anschluss of Austria, leading to a brutal crackdown on Jews, liberals, socialists, and others critical of the Nazi movement. In Vienna alone more than 70,000 people would soon be arrested, mostly because the Nazis prepared in advance.
According to Adolf Eichmann:
"For weeks in advance of the Anschluss, every able-bodied man they could find was put to work in three shifts: writing file cards for an enormous circular card file, several yards in diameter, which a man sitting on a piano stool could operate and find any card he wanted thanks to a system of punch holes. All information important for Austria was entered on these cards.
The data as taken from annual reports, handbooks, the newspapers of all the political parties, membership files; in short, everything imaginable. ...Each card carried name, address, party membership, whether Jew, Freemason, or practicing Catholic or Protestant; whether politically active, whether this or that. During that period, our regular work was put on ice."
These "cards" were IBM punch cards; the file system was operated with IBM machines. The importance of IBM's German subsidiary Dehomag and the IBM machines in the Nazi persecution of Jews, as well as their later extermination efforts, probably cannot be underestimated. IBM's Hollerith machines and their punch cards make it possible for the Nazis to determine who was and was not Jewish, to trace people's racial lineage, to calculate how much they own, to track their movements, and much more.
By mid-1944, the Nazis have Hollerith Departments (Hollerith Abteilung) "installed at the main concentration camps at Mauthausen, Ravensbrüch, Flossenbürg and Buchenwald." The SS Hollerith cards include codes for the grounds for confinement (Jehovah's Witness = 01, homosexuals = 02, Jews = 05), birth date, gender, ethnicity (Reich German = 0, Ethnic German = 1, Foreigner = 2), labor capacity, occupation, and reason for departure (i.e. execution = 3, escape = 4, special treatment = 6). This information is sorted and tabulated to make the administration of the massive camp system possible. Dachau alone will be using 24 IBM machines by the end of the war.
These machines are, in many ways, both the origin of the "surveillance society" and an example of everyone's fears about what happens when powerful authoritarians have too much access to too much information about us.