That was my first NC machine experience with a GE 550 NC control on a special mill I worked on back in 1979. i even learned to use the Frieden tape writer/punched as shown in the video. You typed out the program, early g-code as we know today. Proofread it, if all good then you punched the paper tape. Once the program was "proofed" on the machine, you went back and punched a mylar tape for the final tape to run on the machine.