Seymour Cray, who was practically “Mister Supercomputer” through the 1960s, 70s and 80s, gives a talk at Los Alamos discussing the pending introduction of the legendary Cray-1 <https://www.youtube.com/watch?v=vtOA1vuoDgQ>. The date given in the title is 1976, but he repeatedly makes remarks in the talk that point to the year actually being 1974. He says the new machine will be installed at LANL the following year (actually it went in in 1976).