Comment by prirun

I worked with Prime minicomputers when I was a late teen. They introduced RingNet, a token ring product, in 1979.

Fun fact: each system had an IN and an OUT coax port, and the coax cable was about as thick as a thumb. If a system died, a small hardware box short circuited, tying the IN and OUT coaxes together. This kept the ring intact, but it would also make that segment of the network longer and there were strict distance limitations between nodes. If the distance got too big, the entire ring broke. Also, if any coax cable got damaged, that also lead to a ring break. Prime had a special diagnostic program they could use on multiple nodes to try to find ring breaks.