On 17 March 2015 at 12:49, Phil Budne <[email protected]> wrote: > Johnny Billquist wrote: >> There is a problem in that different emulators might use a different >> layout for memory, that you somehow need to overlap when you come here. >> And that layout can become rather weird, and how do you actually figure >> this out. > > If all simulated memory access is wrapped in C macros, you can hide > most of the ugliness, assuming you don't mind a special build of the > simulators for each multi-processor system. You might end up with > four or more builds of the PDP-11 simulator: uniprocessor, 11-only > multiprocessor, PDP-15 + PDP-11, PDP-10 + PDP-11. > > Since we have CPU cycles to throw away, a "memory server" process > could solve the cache coherency problems... > What of putting the "memory server" process into the PDP-11 simulator, and making it generic? That is, you could have the memory sharing service on the '11 simulator; which you could either configure as a the UC15, KL10 FE processor, or part of the 11/74. It's a more piece of software to program, but much more rewarding than compiling four different simulators, or writing four different new devices.
Also, of note, I brought some of this up back in January 2014: <https://github.com/simh/simh/issues/96> Also discussing implementing the card readers on the '15. Also, other multiprocessor systems that haven't been discussed that might be interesting to talk about are the multiprocessor KL10 systems namely the DECsystem-1088 and DECsystem-1099, the "strange" PDP-11/45+PDP-11/45 setup involving "fun" with UNIBUS B (not good at explaining things, E-11 does it as one of its unsupported configurations), and the dual-processor PDP-15 setup (two PDP-15 CPUs and optionally an FPP connected to one MX15-B). And while we're on the topic of interprocessor/interemulator communications, has anyone thought of perhaps implementing the DX11 with the co-operation of the Hercules team? It might be interesting to see what strange things could be done having the SIMH PDP-11 as a "peripheral" to a System/370, or System/390. -- Christian -- Christian M. Gauger-Cosgrove STCKON08DS0 Contact information available upon request. _______________________________________________ Simh mailing list [email protected] http://mailman.trailing-edge.com/mailman/listinfo/simh
