Tony Duell wrote:
That is why
simulators are so important. You can get most of the feel
of the machine from the comfort of your own home.
No you can't. You can't learn how to load a card reader, disk pack or even
line printer paper on any simulator I know of.
There is a word of mine you may have missed. Look between "get" and
"of".
I (and I suspect others) diepute the 'most'. I can think of far too many
things that a simulator does not provide.
Tony (and others), this response is for all ....
Every time I'be both seem an emulator of a chassic
machine [...] and
also run the real hardware myself, I feel the emultor doens't come
close to the experinece of actually running the classic computer.
In some respects, of course, it can't. In other respects, it can't
until VR technology gets a lot better.
Well, I wastn a simualtor that will give me a painful burn on my hand
when i touch the overheting resisotr. I want one that will kick me across
the ROM if I hapoen to touch the heatsink on the chopper transistor. That
will trip the breaker ot half the house and plunge the room into darkness
if I conenct the virtual 'scope to the mains side of the PSU. And so on.
However, they serve useful purposes nevertheless.
In particular, they
I do not dispute that. THey are however a pale initation of the real
thing. Useful, but by no means the whole stroy.
can give more of a taste of the experience than
most people are likely
to get any other way. And to someone who's got the interest potential
but nothing to spark it, it can be that spark.
Sure. But given that most peole can run the simualtors at home if they
want to, there is little reason for museums to show them (in the same
way that sicne anyone can buy a book of reproductions of Old Master
paintings, there is litle point in having an art gallery that just
displays such books ]1]). The museum should show more -- like the real
machine in operation
[1] Note that I have said nothign about such books (or indeed simulators)
being sold in the appropriate museum shop. That is clearly a Good Thing.
And, for a hands-on museum, a replica panel backed
by an emulator will
be close enough for a lot of people, better in that it's a lot easier
to fix and/or replace if it gets heavy and/or careless use (I'm
thinking schoolkids).
Wby not replcia controls (the bit that is going to get the heavy-handed
interaction) backed by the real machine? Having seen an R-pi at the
weekend, I know hwich out of that and a PDP11 (saY) I'd rather have to
keep running.
... three posts to which you replied ...
(I don't
know why I am adding to this thread which looks destined to go
on and on and achieve little except to demonstrate that different people
have different ideas on how things should be preserved and that most are
not going to change their minds.)
I think that most people here regard a computer as something that runs
particualr software, how it runs it is irrelevant. It's the software that
htey care about, how the OS wa used, ans so on.
I take (as you might expect) a different view. A computer is a complex
digital [1] circuit. The fact that it runs softare is aan interesting
property, but not the main reason I am interested in it. The cirucitry is
what fascinates me. For that reason a simulator is not going to 'do it'
for me.
[1] Yes, I know there are analogue computers. They are interesting too.
But lets not have another tangent... However the analogue parts of a
digital computer -- the power supplies, CRT driver circuits, disk drive
servos, etc are also certainly of great interest to me.
... about.
Also, Tony, I suspect that most of the members of the classiccmp list share
your opinion about simulators or emulators - both programs performing
essentially the same function.
As Tony has stated, he is interested MOSTLY in the hardware of a computer
right down to the individual circuits. YES, software must be used to
run any
computer. HOWEVER, for Tony and many other individuals (probably most
of the individuals on this list), the hardware is the key aspect of the
combined
hardware / software partnership.
Since almost all emulators or simulators have as their primary focus
(usually the
only focus) the accurate execution of any given hardware instruction,
aspects
such as noise, blowing circuits, etc. are almost always beyond the
capability
of an emulator or simulator.
Consequently, as a software addict, I can appreciate why Tony and other
hardware addicts find that an emulator or simulator will never be suffice in
a manner that is satisfactory to run the software of any given computer.
And since I have encountered no one else to share RT-11 enhancements
and bug fixes, it is assumed that no one else is an RT-11 software addict.
(If I am incorrect, please let me know!!!)
On the other hand, as a software addict, when I use the Ersatz-11 emulator,
the ONLY result which is important is that the screen displays results which
have the identical information content. The screen may look a bit different
and the keyboard may have a slightly different configuration. However, that
is not at all important to a software addict like myself. INDEED, sometimes
an emulator may even provide resources that the real (in this case a
PDP-11/83)
computer hardware is unable to provide. Executing the code 100 times as
fast is not a minor advantage. Having disk storage with 1,000,000 times the
capacity and 200 times the throughput is also not a minor advantage. Having
access to RAM which is 1000 times the capacity of the 4 MB available on
the real computer hardware is also not a minor advantage. And last in the
list at this time (but certainly not the only other advantage) and
certainly not
least is the support that Ersatz-11 provides to access the screens of up to
TWELVE ANSI (or VT420 compatible) type terminals by the simple use
of the <ALT/Fn> key combination for which Ersatz-11 currently supports
screens of up to 255 columns by 60 lines. (For those interested, one of
the KED variants which I modified called K42.SAV now supports screens
of that size - if anyone had read this far!!)
To make the point in a different manner, a software addict is interested in
the manner in which the combined software of the operating system, device
drives, utility and application programs interact to produce a useful
result.
Just as the combined hardware components produce the result of running
the software, the combinations of how the software runs produce results
which sometimes seem far more intelligent than the individuals who produce
all that hardware / software partnership. On many occasions, the programs
which I produce are far more able (especially with adequate error checks)
to produce results than what I ever planned in the first place.
In short, as a software addict, an emulator such as Ersatz-11 is far better
than sliced bread. I realize that probably most emulators may have a few
things that cause a bit of a problem for which there is usually a very easy
way to work around the problem. And Ersatz-11 is no exception. BUT,
without Ersatz-11, more than half the fun of making enhancements and
fixing bugs in RT-11 would be missing.
So while I wish the hardware addicts well, viva the software addicts!!!!
Jerome Fine
