Don't forget about the Berkeley Timesharing System[1], Compatible Time-Sharing System[2], or Livermore Timesharing System[3], and a shocking number more[4]. The wealth of diversity even in the late 60's was amazing.

[1]https://en.wikipedia.org/wiki/Berkeley_Timesharing_System

[2]https://en.wikipedia.org/wiki/Compatible_Time-Sharing_System

[3]https://en.wikipedia.org/wiki/Livermore_Time_Sharing_System

[4]https://en.wikipedia.org/wiki/Time-sharing#Notable_time-shar...