dinosaurs mating n. Said to occur when yet another {big iron} merger or
   buyout occurs; reflects a perception by hackers that these signal
   another stage in the long, slow dying of the {mainframe} industry. In
   its glory days of the 1960s, it was `IBM and the Seven Dwarfs':
   Burroughs, Control Data, General Electric, Honeywell, NCR, RCA, and
   Univac. RCA and GE sold out early, and it was `IBM and the Bunch'
   (Burroughs, Univac, NCR, Control Data, and Honeywell) for a while.
   Honeywell was bought out by Bull; Burroughs merged with Univac to form
   Unisys (in 1984 -- this was when the phrase `dinosaurs mating' was
   coined); and in 1991 AT&T absorbed NCR (but spat it back out a few years
   later). Control Data still exists but is no longer in the mainframe
   business. More such earth-shaking unions of doomed giants seem
   inevitable.


Source: The Jargon File