In 1983, the University of California, Berkeley released 4.2BSD UNIX, introducing the sockets networking model that transformed online services. Before sockets, network access relied on slow dial-up connections, acoustic couplers, and programs like UUCP for mail and file transfer over serial lines.

The sockets interface, developed under DARPA contract, reused the UNIX file descriptor abstraction — making network communication as simple as reading and writing files. This allowed rapid development of FTP, Telnet, and SMTP tools that "just worked."

However, the initial 4.2BSD release was buggy; most recipients lacked ARPANET access, and the sockets library couldn't communicate externally. Competing with AT&T's STREAMS model, sockets prevailed due to immediate availability and the absence of legal encumbrances. Bill Joy's new Sun Microsystems soon popularized BSD on Motorola 68000 workstations, cementing sockets as the standard network interface that underpins today's internet.