[Simh] Some beginner questions about RSX11 and/or RSTS on simh...

[Paul Koning]

> On Dec 24, 2019, at 12:06 PM, Dave Shevett <shevett at pobox.com> wrote:
> 
> Hi everyone - happily getting into simh now, reliving my happy
> upbringing on DEC hardware :) . I used to run RSTS on my own 11/34a,
> and did a bunch of other work on RSX-11m on DEC Pro/350's, so very
> much looking forward to reliving some of those times.

You mean real RSX, not POS?

One of these days I should make my RSTS/E for Pro available.

> A couple basic questions....
> 
> 1) I'm assuming RSX-11m is where I should be focusing my work - even
> though my personal systems were RSTS based, (with an occasional boot
> of RT11 to test stuff)  i feel RSX-11m is the more 'complete' and
> modern OS (contextually speaking).  Does this make sense?

Not necessarily.  It depends a bit on what you want to do.  As Johnny points out, if you want TCP/IP, the only RSX will do thanks to his work.  (Or Unix I suppose, but I assume we're talking DEC operating systems.)  If you want to write device drivers, RSX or RT are options, RSTS is not.  (At least not in the sense of something you can do from documentation -- it *can* be done and has been but unless you were part of the RSTS/E engineering team it's quite tough to pull off.)  If you want something really fast and skinny, RT-11 is the obvious answer.  RSTS/E of course is the place for traditional timesharing. 

If you are looking for places to run application programs you might have lying around, RSTS/E is probably a very good answer.  It has both RT11 and RSX emulation that's quite solid.  Some real time features may not be great, though they should be faked adequately.  For example, RSTS doesn't have ASTs or asynchronous I/O (except some disk and tape I/O in V9.0 and later) but the emulation will fake it.  Similarly, you can run user interfaces that feel like RT11 or RSX, at least superficially.  And DCL in V9 or V10 is very good.

	paul