[Info-vax] OpenVMS.Org quick pool

[Stephen Hoffman]

On 2012-08-24 13:22:59 +0000, Paul Sture said:
> 
> 
> This didn't mean that any Dibol program could exceed 32K, just that we
> could run more of them concurrently and hence support more users.

>From ancient and failing memory.... Modula? Modula2? implemented the 
memory management "shenanigans" in the language run-time for RSX-11M?, 
IIRC.

This same windowing was also trivial to do as far back as on an Apple 
II box, though that required add-on expansion memory hardware designed 
to permit windowing.  Those add-on boards were fairly common back then, 
too.

With some applications back in that era, folks used multiport memory, 
which required you to deal with windowing, and with another processor 
that could be playing in your memory asynchronously.  The MA780 was the 
VAX multiport part, and the building block of the VAX-11/782.  I don't 
recall the details of the PDP-11 capabilities off-hand (eg: the 
seldom-seen but variously discussed PDP-11/74), but a quick check of 
some /70 does show references to multiport memory.

Or - as many PDP-11 users did over the years - replace the PDP-11 box 
with either a VAX, etc., or with a PC running Windows, Linux, etc., or 
(these days) with an Arduino or PLC or similar, and avoid the need for 
windowing.  The particular choices depending on what the PDP-11 was 
doing, of course.

These days, dealing with a PDP-11 seems more like somebody involved is 
masochistic (or possibly sadistic), or lost their source code and with 
no budget to replace same, or the wonderfully involved and 
red-tape-entangled mess that is an "approved hardware configuration" or 
whatever the euphemism for "we worked hard so that we can claim we 
can't replace this" is these days.  Well, that or this PDP-11 is 
embedded in a Voyager probe or some such.  The PDP-11 was a nice series 
of boxes in the 1970s and into the 1980s, but that was a few years ago, 
and better and more reliable solutions have become available.


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