[Info-vax] OT: IA-128 ???

[John Wallace]

On Oct 20, 8:06 am, "Bart.Z... at gmail.com" <bart.z... at gmail.com> wrote:
> On Oct 19, 3:19 pm, koeh... at eisner.nospam.encompasserve.org (Bob
>
> Koehler) wrote:
> > In article <paul.nospam-D6099A.13245618102... at pbook.sture.ch>, "P. Sture" <paul.nos... at sture.ch> writes:
>
> > > RSX-11 could address more than 16 bits to support extra RAM, but I
> > > forget the details.
>
> >    Under RSX-11M, when we moved from a 512MB 11/34 to a larger 11/44,
>
> A PDP 11/34, at least those without third-party add-ons, supported a
> maximum of 256 KB memory. The 11/44 supported up to 4 MB.
>
> >    we moved from disk resident to memory resident overlays.  You
> >    still had to work out the overlay, but the overlay manager just
> >    updated the MMU registers, it didn't have to fetch stuff from
> >    the disk.
>
> >    This, of course, leads to different behaviour for memory resident
> >    variables.
>
> >    I don't recall separate I and D space support under 11M, but that
> >    might be because we didn't use it.  Or maybe you needed 11M+ to
> >    get that.
>
> AFAIK, only RSX-11M+ and RSTS/E supported separate I and D space.
>
> Bart

If I remember rightly, I/D space was also implemented on RSX11M+'s
close (but rarely mentioned) relative, IAS.
http://www.john-a-harper.com/ias.html