29 Oct
2017
29 Oct
'17
2:51 p.m.
Folks,
Well I have now found one of Crispin Rope and Mark Priestly's papers on
ENIAC
http://eniacinaction.com/docs/AddressableAccumulators.pdf
It says
"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."
And
"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...
Dave Wade
G4UGM
-----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?
a
-----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:
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
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.
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,,
emulator.
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
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.
limit
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
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