Interesting. As I recall, we never thought of the paging as a big innovation: just what had to be done in order to do anything in a memory space of 128K bytes. You can bet that it presented an interesting challenge in adding the UNDO feature to the existing system. BTW it seems to me that AutoCAD never got much recognition for its technical innovations. One very early example: It was almost certainly the very first program which could run equally well with or without the 8087 floating-point chip (ahem - except for speed!), needing no special user configuration or anything. Credit where credit is due: Not a Walker idea, but an inspiration of one of the unsung super-hackers among the original crew.
This, along with the rest of his website, was written up in a review in the front matter of Science magazine, several years ago. They do not do such reviews often, if ever.
I first heard of his passing in an email from an guy I knew from the olden days at Autodesk. He was passing on an inquiry from Carl Bass (CEO in the first years of the century). Took a couple of days to find a solid answer, which came from a Swiss site that John had posted to in recent years.
BTW, neither the SF Chronicle nor the local Marin paper, San Rafael Independent-Journal, has run an item on this; nor did either evince any interest when I sent them the news. It hardly needs mentioning that Autodesk is very well known in Marin County.
The lack of public notice on the Autodesk site is rather odd; the company management in this century has had nothing like the contempt for the founders that prevailed in the Bartz regime.