On 31-Dec-15 15:53, Paul Koning wrote: >> On Dec 31, 2015, at 3:42 PM, Mark Pizzolato <[email protected]> wrote: >> >> On Thursday, December 31, 2015 at 12:07 PM, Will Senn wrote: >>> On 12/31/15 1:52 PM, Paul Koning wrote: >>>> KMC/DUP are used for the 2780 emulation feature, which is a rather >>>> obscure layered product -- I don't know anything about it. >>> First, I should say that my knowledge of RSTS/E is limited to a half day of >>> trying it out. I appreciate your telling me that you don't know anything >>> about >>> this particular device either. It may seem insignificant, but it helps me >>> categorize things as I learn to know if I should know it or it is actually >>> obscure. >> The KMC/DUP may have been useful for 2780 emulation with real hardware, >> but it is ONLY there for simulator to simulator DECnet connections now. > I wonder if it would actually work with 2780 emulation -- connecting the SIMH > emulated DUP with whatever a 2780 ports looks like in a simulated IBM/360. No. The KMC emulation has some hooks for non-DECnet, but the DUP doesn't. It knows enough to parse the commands to go into the other modes, but doesn't know what to do with them.
The KMC emulation is a functional emulator; although it requires a sensible microcode file (COMMIOP/DUP) to be loaded, it doesn't execute the microcode. There's no point in emulating the KMC-11 microprocessor. (The check for microcode version is partly so the OS goes thru the load process, and partly so that if someone tries to load, say COMMIOP/DZ ucode, the failure will be obvious.) There are some private hooks between the KMC and DUP emulations to make things work reasonably efficiently. DECnet uses DDCMP, which is a character oriented counted-length protocol. Bisync is a character-stuffing protocol. The bit-stuffing protocols (e.g. SDLC, X.25) are supported by the real KDP, but not by the emulation. The KDP emulation can be told to introduce CRC errors once in a while, so you can watch error recovery work and enjoy the network management tools. Extending the KMC emulation to deal with other ucodes and/or protocols is certainly possible. But non-trivial. Happy coding. I did test the KDP emulation with DECnet on the PDP-11 (rsx) as well as VAX and the KS10. > As for DECnet, yes indeed. Note though that RSTS/E does not support that > combination for DECnet; the only DECnet devices it supports are DMC11 (from > the start), DMV11 and DMP11 (V7.1 and up), Ethernet (V9.3 and up), and > software DDCMP on terminal ports (not clearly supported but present if you > dig enough (V9.6 to some extent, V10.0 in cleaner form). So synchronous > DDCMP is DMC and friends only (unless you count the Pro printer/console USART > work I did as a midnight project in V9.6). > > paul > > > _______________________________________________ > Simh mailing list > [email protected] > http://mailman.trailing-edge.com/mailman/listinfo/simh
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