[Info-vax] Some questions on software for VMS 7.3 VAX

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On Wed, 20 Jan 2016 19:42:13 +0100
hb via Info-vax <info-vax at rbnsn.com> wrote:

> On 01/15/2016 03:03 PM, John E. Malmberg wrote:
> > On 1/15/2016 5:00 AM, hb wrote:
> >> Maybe I didn't make it clear, to me this is a simh problem, not an
> >> Emacs problem. The overrun shows in DCL. I didn't try to debug the
> >> hang in Emacs.
> > 
> > It is entirely possible that the SYSTEM-W-DATAOVERUN can be reproduced
> > with a physical VAX of the same speed or slower rating as the SimH
> > system.
> > 
> > The DZ device family does not have buffering and will not work reliably
> > for high speed input.
> > 
> > Using them for high-speed output is self-limiting.  They will chew up so
> > much CPU that it will throttle the output, and anything else you are
> > attempting to do.
> > 
> > It is also possible to bugcheck a physical VAX by sending data to
> > multiple DZ interfaces too fast at the same time.  I have seen it happen
> > multiple times.  The only fix is to change to using a better serial
> > controller.
> > 
> > A DZ interface is basically good enough for human typing speed.  If you
> > are trying anything faster over it, you are rolling the dice.
> > 
> > Which is why trying to use the serial console of a VAX for anything
> > other than system maintenance very bad idea, since that is almost always
> > a DZ port.
> 
> Whoever is interested, for other reasons I upgraded simh from "VAX
> simulator V3.8-1" to "MicroVAX 3900 simulator V4.0-0 Beta git commit id:
> db3531e5" and "the DZ problems" no longer show.

I'm hoping they eventually get the idle working for OpenBSD hosts. I have
one box dedicated to SIMH but it runs 85% whenever SIMH is running.

Did you notice any important upgrades or regressions? I've been pretty
happy with 3.9, not that I stress it very hard. But so far no bugs. Nice
piece of software. I wish everything was written so portably and well.

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