Four decades ago, when the Berkeley Internet Name Domain Server launched, it stored DNS records in "zone files". You could edit these files in vi, but BIND had to be told to reload them before your changes took effect. Later, other DNS servers came along, like Daniel Bernstein's tinydns, which served records directly out of a database on disk — but even there, after editing the human-readable DNS records, it was necessary to recompile the database file.