Starting with the Project GENIE system[1], the primary paper on the software is by Butler Lampson[2], although he did it with Peter Deutsch, then an undergraduate at Berkeley. This system was picked up by Tymshare and almost completely rewritten whilst maintaining compatibility. When it was connected to Tymnet[3], the whole character handling section of the monitor (as an OS was sometimes known) had to be rewritten. All of these changes were described in a IEEE Annals on History of Computing paper[4]. For those desiring more specific information on the "subsystems", much of it can be found on bitsavers: https://www.bitsavers.org/pdf/tymshare/ [1] The GENIE system is the correct historical name for this system. [2] "Interactive Machine-language programming", B. Lampson, 1965 AFIPS conf. [3] "TYMNET: a terminal oriented communication network", L. Tymes, 1971 AFIPS conf. [4] "Tymshare's Changes to the Project Genie SDS-940 Operating System: A Historical Review", M. Kahrs and A. Hardy, in *IEEE Annals of the History of Computing* in July–September 2021