ITS (Incompatible Timesharing System) was a timesharing system developed at MIT in 1967, initially for the PDP-6 and later primarily on PDP-10 computers, notable for its lack of security features like passwords. The SDF ITS is currently accessible at
https://hactrn.org/ via a KA10 emulator and offers tutorials for basic use and exploration of classic programs. Users are encouraged to log in, create a directory, and explore programs like Zork, Emacs, Maclisp, and C through provided hints and documentation.