[Simh] New simulator - VAX-11/782

[Paul Koning]

> On May 19, 2017, at 6:15 PM, Matt Burke <matt at 9track.net> wrote:
> 
> Ok, so now it's time to reveal the new 'device' I've been working on
> that I mentioned a few days ago. It is in fact the MA780 multi-port
> memory as used by the VAX-11/782. Simulator source is now on Github and
> binaries (for Win32) are available on my website along with a guide on
> how to setup VAX/VMS for asymmetric multi-processing:
> 
> http://www.9track.net/simh/vax782/
> 
> This simulator relies on a new module 'sim_ipc' which has O/S specific
> code for inter-process communication. This module should work on at
> least Windows, VMS and POSIX compliant UNIX variants but no doubt some
> more work will be required in this area to make it truly portable. There
> are a few known issues as noted on my website but please try this out
> and let me know how you get on.

Interesting.  So you have the two CPUs as two processes?  I wonder if doing them as threads in a single process might be more straightforward.  I did an implementation of dual CPU CDC 6000 emulation that way (an extension to Tom Hunter's DtCyber).  Posix threads (pthread) work nicely, and semaphores (which aren't strictly part of pthreads but are often found alongside such implementations) often come in handy as well.

	paul