> -----Original Message----- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Paul > Koning via cctalk > Sent: 29 October 2017 12:42 > To: Eric Smith <space...@gmail.com>; General Discussion: On-Topic Posts > <cct...@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 <cct...@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 a Turing machine that could emulate or simulate the behaviour of any arbitrary Turing machine... https://en.wikipedia.org/wiki/Universal_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 https://en.wikipedia.org/wiki/ENIAC#Improvements well that's what Crispin Rope asserts, but his book is still copyright and I can't find any reference to this on the net,, > That's certainly a successful early commercial implementation of emulation, > done using a particular implementation approach. At least for some of the > emulator features -- I believe you're talking about the 1401 emulator. IBM > 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 seems > 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 limit > 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 one > in IT (consider "data set"). And in particular, as was pointed out before, > "emulator" has a quite specific (and different) meaning in the 1980s through > 2000 or so in microprocessor development hardware. > > paul Dave