[Simh] Re: Other simulations

[A.Bucher at alcatel.de]

Hi,

>Has anybody ever considered trying to simulate things that are not
>central processing units?
>
>I'm thinking of things like Cisco routers.  That would be a little off
>the original purpose of SIMH.  Yes, a Cisco 2500  series router is a
>"historically significant computing device", but the impetuous for it
>would be all of us trying to learn Cisco routing to get certified.  I
>think the 2500 uses a 68000 cpu chip.  I suspect the interfaces are not
>published, so that might make it impossible, but I don't know.

Yes, why not, but where's the fun ?
A router is just some blackbox sitting somewhere in a dusty, smelly dark
room,
while the CPU has all the glory in a bright lit data center with glass
windows and AirCo ... :-)

No, to be more specific: Why not ?
It should be possible to "emulate" anything, as long as it is
well understood and/or documented. But
a) people tend to start with the interesting bits, and
b) the more generic a item to emulate is, the more useful the emulation
gets.

I mean, with a CPU (chip) emulator, you can create different computer
emulations,
and on that you can run general-purpose programs, either for historical
reasons,
or even for continued productivity with existing software on new hardware.

With the router emulation, you can only have the router functionality, and
that's it,
mainly because there are no general-purpose applications available.

Okay, maybe you can start porting Linux or the like on the router hardware,
(e.g. I gave some NCD X-terminals to some guys porting linux on it - ON the
X-Term, of course, not on the host),
or the emulation at least is good for the preservation of knowledge.

But, to go back to the VAX emulations, I was thinking about emulating
peripherals like the large RA disks
(they also have at least two CPUs), or tape units, or an HSC. But for
practical use, it makes no real sense,
because the "mass data storage" part of a computer is not really importand
to be emulated in detail.
Again: On all this items, no "general purpose" software is running,
therefore you can treat it as a "black box"
and emulate only the interfaces (like for router) to get the same
functionality. It all depends on the level of "genuity" you want to have.

Andreas

PS: For some "nice" emulations, check out MAME (I think the idea is similar
to SIMH, having a general-purpose basic emulator and lots of different
specific emulations done with it, all using the same interfaces. And to get
to the fun part, where the mechanical items come in, check out PinMAME, the
pinball emulator. There, somebody had the idea to join the "cpu board/IO
emulation" and the "3D simulated mechanical parts simulation" to get a
fully simulated 3D representation of a device (i.e a Pinball game)
originally consisting of mechanics, electronics and program code - truely
ingenious, I think. (they even emulate relay-controlled EM pins using the
same emulator, all with a bit of VB code).

PPS: Why not emulating biological "things" ? they are also no CPUs :-)
anybody interested ?