[Simh] RT-11 source

[Rhialto]

On Sat 22 Oct 2016 at 23:03:41 +0200, Johnny Billquist wrote:
> On 2016-10-22 18:55, Al Kossow wrote:
> > 
> > 
> > On 10/22/16 7:44 AM, Ray Jewhurst wrote:
> > > I have an idea for project to teach my self rudimentary OS design and I would like to use RT-11 as an example
> > > 
> > 
> > Did anyone ever port MINIX to the PDP-11?
> 
> I don't think so. I suspect it would be non-trivial, as the memory
> limitations of the PDP-11 require that you sometimes need to design with
> that in mind from the start, or else face serious problems.

But the original 8086 MINIX (which I used in university in the course on
operating system design) used "small memory model". That means it sets
the segment registers for each process to a fixed value and therefore
its processes (including kernel server processes) were limited to 64KB
of text and 64KB of data. That would fit with PDP-11s with sepid just
fine.

At some point during inter-process communication it no doubt uses the
segmentation registers more actively (I don't remember the details) but
that can be done in some other ways on the -11.

> 	Johnny
-Olaf.
-- 
___ Olaf 'Rhialto' Seibert  -- Wayland: Those who don't understand X
\X/ rhialto/at/xs4all.nl    -- are condemned to reinvent it. Poorly.
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