Nodes are added to the ARPANET at the rate of one per month.Programmers Dennis Ritchie and Kenneth Thompson at Bell Labs complete the UNIX operating system on a spare DEC minicomputer. UNIX combines many of the time-sharing and file-management features offered by Multics and wins a wide following, particularly among scientists.
Bob Metcalfe builds a high-speed (100 Kbps) network interface between the MIT IMP and a PDP-6 to the ARPANET. It runs for 13 years without human intervention. Metcalfe goes on to build another ARPANET interface for Xerox PARC’s PDP-10 clone (MAXC).
DEC announces the Unibus for its PDP-11 minicomputers to allow the addition and integration of myriad computer-cards for instrumentation and communications.
In December, the Network Working Group (NWG) led by Steve Crocker finishes the initial ARPANET Host-to-Host protocol, called the Network Control Protocol (NCP).