PDP-11 data and function address spaces (was External ptrs and arrays)

[Henry Spencer]

In article <5121 at ncar.ucar.edu> thor at stout.UCAR.EDU (Rich Neitzel) writes:
>>Dept. Of Really Fussy Nit-Picking:  relatively few pdp11s, and relatively
>>few pdp11 operating systems, supported split-space -- Unix on the 44/45/70
>>was just about the sole example 
>
>Alas, you have forgotten the 11/73 and 11/83. Also, RSX-11M+ uses I&D space
>extensively, even for the kernel...

If we're being really picky, the 73 was an lsi11, not a pdp11.  The 8n is
a slightly different story, but I can always hide behind the "just about"...

RSX-11M started using split-space pretty late in the game.  Early on, Unix
was notorious for giving the 11 MMU much more of a workout than any of the
DEC systems did.

>BTW, why do UNIX people seem so unfamiliar with DEC's Q-bus PDP's?

Probably because good ones did not become available until the pdp11's days
as a desirable Unix machine were already visibly ending.
-- 
A bit of tolerance is worth a  |     Henry Spencer at U of Toronto Zoology
megabyte of flaming.           | uunet!attcan!utzoo!henry henry at zoo.toronto.edu