Another operating system for Model 16s was RM/COS- a COBOL operating system. This was popular because it was smaller than Xenix on your 8 MB hard drive. There is not much information about it, but check out this cool catalog from 1986 (Model-II was "Tandy-6000" by this point- I see there is a punch card reader available..):

https://www.thecomputerarchive.com/Catalogs%20and%20Price%20...