On Jun 19, 2024, at 1:49 AM, Dave Horsfall
<dave(a)horsfall.org> wrote:
Sort of between kernel and user mode, Unix [zillion trademarks etc] never
used it. but did RSX-11?
I don’t know about RSX-11.
Back to UNIX: Supervisor mode probably never ran any code, but its memory management
registers were used in m45.s in functions copyseg and clearseg.
—Milo