Ngnghm was fascinated by our keyboards: because of physiological differences between our races, similar devices had never been imagined by Houyhnhnm computing engineers. Now, as he was watching me closely, Ngnghm noticed that I was punctuating most of my typing with recurring combinations of key chords. I told him I had no idea what he meant; and so he had me record and review how, after every sentence or so, or before changing activities, I was composing the sequence Ctrl-X Ctrl-S, or Command-S, or some other mantra that varied slightly with the application I was using. Interestingly, I wasn’t even aware that I was doing that before he told me! What was this mantra doing, he inquired? How could I possibly repeat it without even noticing — and why would I? I told him that depending on the application, each of these mantra saved the current file, and that typing it had become ingrained in me as a subconscious habit, because I used it so often, out of necessity. What does "saved" mean wondered Ngnghm, and what made it a necessity?