Most of IBM's product numbers are annoyingly random, but sometimes marketing gets it right, as in the case of the System/360. Amusingly, the aerospace version o

Most of IBM's product numbers are annoyingly random, but sometimes marketing gets it right, as in the case of the System/360. Amusingly, the aerospace version of System/360 is called System/4 Pi: these computers are operating in three dimensions, and just as a circle has 360 degrees, a sphere has 4π steradians. IBM also had System/370 which was the 1970s version of the 1960s System/360, and similarly System/390 in the 1990s.