Digital Equipment Corporation's PDP-11 series. This architecture was No.1 in the minicomputer business for many years, since the introduction of the first -11 in 1970, and... it's not dead. Many of these machines are still in use and Mentec still produces modules (processors) and operating systems for this platform. They're sure the PDP-11 is ready for the year 2000, and they know what they're saying...
Anyway, the PDP-11 series is already a legend, many of today's computer specialists cut their teeth on -11's at universities and colleges. The machine was so popular, that it was actually "cloned "in Hungary, The Soviet Union and Bulgaria when the Iron Curtain existed! But that's another story!