On 18 Sep 2020, at 10:35, William ML Leslie <william.leslie.ttg@gmail.commailto:william.leslie.ttg@gmail.com> wrote:
Not to mention that the multics driver rings are a fairly dark corner of the processor these days, since no operating system appears to make use of 1 and 2, so nobody is inspecting them for hardware bugs.
Correct, for the basic reason that there is no benefit from running things in rings 1 or 2, you can just run them at ring 0. Also, you can safely expect poor performance (eg systenter/sysexit aren’t supported).
Gernot