From: tombaker@world.std.com (Tom A Baker)
Subject: Re: Apple ][ Emulator?
Organization: Me, at The World Public Access UNIX, Brookline, MA
Date: Wed, 7 Oct 1992 12:01:08 GMT

In article
 <1992Oct6.205004.5366@javelin.sim.es.com> mmunson@animal.es.com (Mark Munson)
 writes:
>In article <59@MECHANICAL.watstar.waterloo.edu> Jeff Markus writes:
>
>>I am wondering if there are emulators out there for the MS/DOS computer
>>which I can use to run Apple // DOS 3.3 and/or ProDOS programs?
>
>>If there is such a thing, is it any good?  Where might it be available?
>

There is such a beast ... Can you FTP?  It is on avalanche.berkeley.edu (I
think that's right, it's in the FAQ) in the directory /pub/AppleII or
/pub/nyet (I was looking at it just Monday night.

As for whether it is "good", there are two aspects of it.  ONe is that
it is VERY good... the guy emulates the 65C02 and then dumped all the
ROMs from the motherboard and the I/O slot boards; very in-depth simulation
in that EVERYTHING is simulated.  And apart from a few minor bugs it works
blindingly well.

Two ... the machine simulated is an unenhanced IIe with 64K and two 5-1/5
drives.  No 80-columns, no mousetext.

You need at least a 286 to run it, and you're supposed to have CGA/EGA or
better.  I find that it does run with a Hercules card with a simulator,
but that method has an annoying drawback or two.

On that first hand, ... I ran it on a friend's 386 EGA, and I was breathless.
It really is a tour-de-force.  Reading through the code I found unimaginable
things...nibble encoding and decoding in the disk card code, for instance.

>A software emulator is possible, but it would require a lot of work, since
>the Apple ][ is not device independent.  Nearly all Apple ][ commercial
>software uses routines that directly write to soft-switch and display
>memory.  Since nearly nobody is using the firmware routines, you can't
>just intercept the calls and be done.  An Apple II emulator would have to
>look-up from a big table, all of the soft-witch locations and be able to
>convert those to DOS calls.  This is no small task, and many of the calls
>are timing dependent, making emulation very-very difficult.
>

Everything said there is true ... the guy did it, that is all.  Nearly`all
the Apple memory map is the result of dumping ROMs, and his I/O page is the
spot where he examines addresses and converts the I/O to MSDOS I/O.


MY CONCLUSION: I've been wanting to toss some emulation questions into
this group for a while... this just rushes some of them.  I'm looking for
an alternative to this simulator.  I'd love to run an enhanced IIe simulation
on my 80; I'd like to carry one of my AppleWorks databases around.

2) Please let me know if there *IS* another emulator around, or if someone
has re-assembled the one in question for sub-286 pc's, or enhanced the IIe
being simulated.

3) Whaton earth has happened to that UNIX IIe emulator that I read about in
  the FAQ?  It was supposed to be in the avalanche machine, and now I haven't
  even been able to scare it up with archie?  It was supposed to be in C,
  and porting it wasn't out of the question.

Please stay in touch.

(BTW, that avalanche directory also has a nice utility for porting the Apple
disks over to the PC.)

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