> 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.
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
