Which Dec Emulation is the MOST useful and Versatile?
dave.g4ugm at gmail.com
Sun Oct 29 13:51:55 CDT 2017
Well I have now found one of Crispin Rope and Mark Priestly's papers on
"ENIAC's original control method was modified in 1948, after which point its
wires and switches were left mostly untouched while it ran only a single
(but slowly evolving) program: a microcoded interpreter for a virtual von
Neumann architecture machine."
"ENIAC's application programs were written as a series of two digit
instruction codes for this virtual machine and loaded into its read-only
function table memory by turning knobs to set digits."
I would therefore argue that "emulation" is as old as computing itself...
> -----Original Message-----
> From: Dave Wade [mailto:dave.g4ugm at gmail.com]
> Sent: 29 October 2017 15:54
> To: 'Paul Koning' <paulkoning at comcast.net>; 'General Discussion: On-Topic
> and Off-Topic Posts' <cctalk at classiccmp.org>
> Subject: RE: Which Dec Emulation is the MOST useful and Versatile?
> > -----Original Message-----
> > From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Paul
> > Koning via cctalk
> > Sent: 29 October 2017 12:42
> > To: Eric Smith <spacewar at gmail.com>; General Discussion: On-Topic
> > Posts <cctech at classiccmp.org>
> > Subject: Re: Which Dec Emulation is the MOST useful and Versatile?
> > > On Oct 28, 2017, at 10:09 PM, Eric Smith via cctech
> <cctech at classiccmp.org>
> > wrote:
> > >
> > > IBM invented computer emulation and introduced it with System/360 in
> > 1964.
> > > They defined it as using special-purpose hardware and/or microcode
> > > on a computer to simulate a different computer.
> I am not sure they invented computer emulation. I think that the concept
> Emulation/Simulation is as old as, or perhaps even older than computing.
> Whilst it was a pure concept Alan Turing's "Universal Turing Machine" was
> Turing machine that could emulate or simulate the behaviour of any
> Turing machine...
> .. and somewhat later when ENIAC was re-wired to execute programs stored
> in the function switchs, this was a partial simulation/emulation of EDSAC
> well that's what Crispin Rope asserts, but his book is still copyright and
> find any reference to this on the net,,
> > That's certainly a successful early commercial implementation of
> > done using a particular implementation approach. At least for some of
> > the emulator features -- I believe you're talking about the 1401
> > didn't use that all the time; the emulator feature in the 360 model
> > 44, to emlulate the missing instructions, uses standard 360 code.
> > It's not clear if that IBM product amounts to inventing emulation. It
> > likely there are earlier ones, possibly not with that particular
> > choice of implementation techniques.
> > > Anything you run on your x86 (or ARM, MIPS, SPARC, Alpha, etc) does
> > > not meet that definition, and is a simulator, since those processors
> > > have only general-purpose hardware and microcode.
> > >
> > > Lots of people have other definitions of "emulator" which they've
> > > just pulled out of their a**, but since the System/360 architects
> > > invented it, I see no good reason to prefer anyone else's definition.
> > "emulation" is just a standard English word. I don't see a good
> > reason to
> > its application here to a specific intepretation given to it in a
> particular IBM
> > product. It's not as if IBM's terminology is necessarily the
> > predominant
> > in IT (consider "data set"). And in particular, as was pointed out
> > "emulator" has a quite specific (and different) meaning in the 1980s
> > 2000 or so in microprocessor development hardware.
> > paul
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