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

[hb]

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.