[TUHS] quick question on PDP-11 addressing

[Phil Budne via TUHS]

John Levine wrote:
> ... there was an eight-entry map that
> mapped 8K pages of program addresses to 8K pages of physical memory.

DEC docs (or at least the KT11-C document Clem posted a link for) call
them "variable size pages"; each of them can map anything from 32
words up to 4KW (8KB), but I think it's fairer to think of each (mode
x I/D) virtual address space as broken into eight segments at 8KW
boundaries.  Each segment has the option to grow from up from the
bottom of the segment, or down from the top.

Not all systems make it easy to restart an instruction after a "fault"
like one might expect from hearing the word "paging"

CB (Columbus Bell) Unix, and SVR1 ran on 11's and supported shared
memory segments.