Operating Systems

Below are as many of the myriad operating systems I have used as I can recall.  I started out when we had no idea what would become the dominant player, so we had to learn all of them.  I think it gives me an edge in system "biodiversity" since I know other ways to do things, not just the most common way today.  Like visiting foreign countries, it opens your eyes to other ways of thinking, other foundational concepts.