Ngnghm decided that while stranded among us Humans, he would conduct an ethnographical study of Human computer systems, and took to heart to examining my programming habits. In return, I was more and more curious of how Houyhnhnm systems worked, or failed to work. That’s when, trying to imagine what the Houyhnhnm computing systems might keel over, with their making everything persistent, I had this a-ha moment: surely, they must have extreme trouble with live upgrade of their data schema, and their programmers must spend their time in hell trying to reconcile modifications in what amounts to an unrestricted distributed database, that anyone can modify at any time. Ngnghm wasn’t sure what I was talking about that could be a major issue, and so interrogated me as to the Human practices with respect to handling change in persistent data. And he found that many of the issues stemmed from limitations with how Humans approached them; these issues were not intrinsic with the problem of ensuring persistence of data, and all but disappeared if you considered code change transactions as first-class objects.