In November 1983 Paul Mockapetris, at USC's Information Sciences Institute, publishes RFC 882 and 883, defining DNS as the hierarchical, distributed name-resolution system for the Internet. It replaces the single centralized HOSTS.TXT file, which could not scale with TCP/IP's 1983 adoption. DNS's delegated-zone tree architecture — the same mechanism serving thousands of hosts in 1983 now serves over a billion active domains without structural changes. Without DNS, the Web as conceived by Berners-Lee in 1989 would not be viable at consumer scale.