On Jul 8, 2015, at 5:39 PM, Bob Supnik <b...@supnik.org> wrote:
> First, congratulations to Mark for running the current Ultrix 750 problem to
> earth.
>
> Second, a brief diatribe about the need for fidelity to the hardware in the
> VAX simulators, which is (on the face of it) lacking outside the 3900 and 780
> simulators.
>
> I have preached and documented the need for reasonable fidelity to hardware
> in implementing simulators. The papers on the SImH web site are filled with
> examples of minute details gumming up software behavior if a simulator gets
> them wrong. It looks to me like the 750, 730, 8600 are cut-and-paste jobs on
> the 780, and the MicroVAX I and II on the 3900. I admit there are strong
> family resemblances and, in some cases, reuse of hardware (the 8600 uses some
> of the 780 IO adapters), but as Ultrix proved, running VMS is an insufficient
> proof of correctness. Without reading (and implementing) the gory details of
> all the system-specific hardware, something is going to break. And if the
> goal is just to run VMS, why bother with variant models? The 780 and 3900
> between them cover the complete history of VAX/VMS, Ultrix, and all the BSD
> variants.
>
> While the 750 now runs Ultrix, will it run the next OS it is given? Even with
> the current fix, there are multiple errors remaining in the UBA. The 730
> won't boot Ultrix off the RB80; and so on.
>
> So my challenge to the community is twofold. First, is there more
> documentation on the variants available somewhere? I haven't found microcode
> sources or listings for the 750, 730, MicroVAX I, or 8600, for example.
> Second, are people prepared to "adopt" a model, read its documentation, and
> clean it up?
>
> End of diatribe.
>
> /Bob
Let’s not forget different peripheral usage models between the various OSs. I
have an open issue where Ultrix 2.0/2.2 run fine on a Microvax II, but as soon
as I enable DECnet the system panics with:
panic: qe: Non existent memory interrupt
Mark, were you able to reproduce this problem with the updated image I pointed
you at?
John.
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