I remember hearing this paper presented at USENIX 1998, in New Orleans.
IIRC, the most interesting part of the presentation was a slide titled "Is UNIX portable?" Miller said, of course it is, I ported it! But then he showed a chart with the number of lines of code in the distribution and the number he had to replace for the Interdata mini, and the proportion was quite large! His punch line was that yes, he had ported UNIX, but it wasn't quite so clear that you could call it portable.
I did something similar, porting first V6 then V7 to the Vax some time starting in '79 ... The process started with writing a tar clone in fortran to get the C source off of the tape, luckily I had a C compiler for VMS ...
The result was a Unix that ran VAX native in a VM, each copy ran in a single VMS process ... Then I did V7, much easier the second time around
Oh, and that famous comment "you're not expected to understand this" .... Completely obvious about 2 months in when you come at it from the right direction (swapping a process in)
As far as I can tell, the paper you link definitely confirms the essence of what Miller Says.
The end of the link says "We here at Bell Laboratories were truly dumfounded when this visitor from an unknown school in Australia reported his elegant procedure and remarkable success. Our own people took considerably longer to move UNIX
to an Interdata machine, not because they were not as
clever but because they had a different objective: a
portable Unix rather than a UNIX port. But I think they'd
. have blinked before undertaking the heroic effort that
Richard Miller did and he did not even have a Unix
computer to port from. "
IIRC, the most interesting part of the presentation was a slide titled "Is UNIX portable?" Miller said, of course it is, I ported it! But then he showed a chart with the number of lines of code in the distribution and the number he had to replace for the Interdata mini, and the proportion was quite large! His punch line was that yes, he had ported UNIX, but it wasn't quite so clear that you could call it portable.