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From: don@brillig.umd.edu (Don Hopkins)
Newsgroups: comp.sys.apple2
Subject: Re: System programming for the Apple II (preferably the IIe)
Message-ID: <23029@mimsy.umd.edu>
Date: 11 Mar 90 07:02:15 GMT
References: <6673@hydra.gatech.EDU> <12316@smoke.BRL.MIL>
Sender: news@mimsy.umd.edu
Reply-To: don@brillig.umd.edu (Don Hopkins)
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 47

In article <12316@smoke.BRL.MIL> gwyn@brl.arpa (Doug Gwyn) writes:
>In article <6673@hydra.gatech.EDU> ccastjr@prism.gatech.EDU (COOOOoooooOOOoooOOOKIE!!!!) writes:
>>how possible is it to write the "assembly only" sections of unix, and then 
>>compile the C sources for unix on a Apple II?
>
>I keep trying to tell you guys that it's not that simple!
>The assembly-language is just the part that is blatantly
>OBVIOUSLY machine-dependent.
>Most of the machine-architecture dependence of the UNIX kernel
>is actually reflected in C source code, not assembly language.
>Porting UNIX to another hardware platform is NOT repeat NOT a
>job for amateurs.

Hi, Doug. Remember me from the days of info-apple? Anybody else
from the old info-apple mailing list still around? I'm still using
my Apple ][+, typing on it right now. 80 column videx card, full
ascii keyboard, CPU in a wooden box I screwed together myself.
Home brew Forth system with a hand written termulator. It does what
I want very nicely -- it's a great terminal. But why would I ever
want to run Unix on it???

Let's face it: Unix sucks. And there isn't a word strong enough to
describe how bad it would be running on a 6502, even if it *were*
possible. The Apple ][ is a neat little computer, but why would you
want to eat it up running Unix? What's the point? A status symbol?
Is there some particular Unix application you want to run? Port the
application, you don't need the damn operating system. Look at all
the Unix programs that have been ported to (eech) MS-DOS. What you
need is a good 6502 C compiler, not a bloated operating system.

I would like to have a good 6502 emulator that runs under Unix.  A
switch statement for all the opcodes would work fine, since any
compiler worth using will compile a dense switch statement into a
jump table. (Torek wrote a Z80 simulator a long time ago that
worked that way.) I don't see why it should be specific to X
though. (X sucks, too.) The hires graphics memory mapping would be
a bitch. [but certainly more tractable than porting Unix to a
6502!] (BTW: Has anybody written an Apple hires <=> pbm image
converter?) You would definitly not want to simulate disk I/O at
the hardware level, with all the timing and nybble mashing
involved, it would be *much* better to write a higher level ProDOS
block driver that hooked into the simulator.

	-Don

PS: Does anybody have a copy of the Apple contributed program
library disk with the Lisp interpreter written in Basic?