Incompatible Timesharing System
From Computer History Wiki
The Incompatible Timesharing System (usually ITS) was an early time-sharing operating system; initially for the PDP-6, and later for PDP-10's. It was developed at MIT in the Artifical Intellegence Lab, after Multics was done by Project MAC.
It ran on KA10s which were modified with MIT-designed and built paging hardware (which that generation of PDP-10 did not have); it later ran on the KL10 and KS10 as well.
ITS was one of the first OS's connected to the ARPAnet, and it was on an ITS system that the first versions of Zork were created.
Some information on installing & images can be found here.
