[Simh] simh vax750 or vax730?

[Hittner, David T.]

I suspect no has looked at creating (or will ever look at, unless it's
you :-) a VAX-11 725/730/750 simulator.

The main VAX of the SIMH project is the QBUS-based MicroVAX 3x00.

The VAX-11/780 was added much later, for historical interest, since it
was the original VAX. The creation process took a long time, and Bob had
to re-engineer and re-discover many of the original components, as well
as "hack"ing up a limited simulation of the LSI + floppy console
subsystem to enable the system to boot.

The VAX-11/725/730/750 had many different hardware components, which
would require fairly extensive work to simulate. They all had different
consoles; different cpu implementations; different memory controllers;
the 730 had the CPU-assisted R80 (not RA80) disk and T80 (not TA80)
tape; and the 725 had the dual-drive/single-spindle RC25 disk subsystem.
The only thing that would make those simulator(s) easier to write is the
ability to reuse the existing UNIBUS peripherals.

Having worked on all of those critters at the time, I don't see any
advantage in simulating them in addition to the existing VAX-11/780.
Honestly, they were a bit of a pain. The MicroVAXen were much better.
:-)

Dave

> -----Original Message-----
> From: simh-bounces at trailing-edge.com 
> [mailto:simh-bounces at trailing-edge.com] On Behalf Of Brad Parker
> Sent: Friday, December 26, 2008 5:18 PM
> To: simh at trailing-edge.com
> Subject: [Simh] simh vax750 or vax730?
> 
> 
> Has anyone looked at making vax-11/750 and vax-11/730 (or 
> 725) specific versions of simh?
> 
> I've been playing with "vax780" and having flashbacks to real 
> hardware (I once had a 780 to myself - it made a great single 
> user workstation :-)
> 
> But I really want 750 and 730 specific versions to test 
> booting of things like netbsd before I run on real hardware.
> 
> Has anyone done this or looked into it?  just curious.
> 
> vax780 is great, but the hardware can't be turned into a 750 
> or 730 via a config file (because, for example, the unibus 
> moves all around along 20 other things which come and go)
> 
> I suppose the right thing is to generalize it all, but a good 
> start (before remembering how to spell "nexi" :-) would be to 
> just make up 750 & 730 specific sources...
> 
> -brad
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