It's referring to the "Open Systems" hype of the 80s / early 90s. The term "open source" became popular only much later. https://en.wikipedia.org/wiki/Open_sys

It's referring to the "Open Systems" hype of the 80s / early 90s. The term "open source" became popular only much later. https://en.wikipedia.org/wiki/Open_system_(computing) https://en.wikipedia.org/wiki/Open_system_(computing)