[Simh] BDV11 or loading roms in SIMH

[Stephen Hoffman]

Circa Wed, 3 Jun 2009 22:46:54 +0200, SPC <spedraja at gmail.com> asks

> Is SIMH capable to load and execute ROMS which could execute later a
> bootstrap and so ?
> Would be possible to create one general device named ROM...


Depending on exactly what you are up to...

The KA630 CPU Technical Manual has a description of what the Q-bus  
PROM footprint looks like.

See page 3-17ff at:  http://bitsavers.org/pdf/dec/vax/630/EK-KA630-UG-001_Feb86.pdf

With OpenVMS VAX (or MicroVMS), it is VMB that looks for this  
signature and not simh, and VMB that calls into it.

The old-time hack was an MRV11, but other gizmos have deliberately  
left that signature in Q-bus memory space, too.

With the PDP11 pieces, I don't know.  But a quick search of the simh  
source pool might show a detail or two.  The PDP-11 boxes I've dealt  
with either executed code off of a device boot ROM (halt, set the  
toggles for the CSR address, load and go), or you ended up toggling  
the whole bootstrap in from the switches. 
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