INFO-ATARI16 Digest         Wed, 22 Nov 89       Volume 89 : Issue 692
 
Today's Topics:
                  6502 - the ultimate (?) emulation
  Blitter disappointment (was: Time to create comp.sys.atari.flames)
       Experience with Toshiba 3 1/2 inch double sided drives?
          Gadgets by Small - Possible new '030 add-on board!
                        Hard Drive Woes: HELP!
                            Vapourware!!!
----------------------------------------------------------------------
 
Date: 21 Nov 89 10:10:51 GMT
From: mcsun!unido!uklirb!incas!hoenig@uunet.uu.net  (Helmut Hoenig)
Subject: 6502 - the ultimate (?) emulation
 
Is there any use of a VIC20-Emulation on the ATARI ST ?
 
I wrote one to test a new kind of emulation: The 6502-code of the VIC20-
Machine is not interpreted the usual way. It gets *translated* in 68000-Code
at run-time. That means: If a statement is reached for the second time, it is
already translated. This gets very difficult, especially if self-modifying
code is alowed (already the Commodore-Basic uses it).
 
My final results:
 
- It needs a *lot* of memory:
      The memory of the Atari is sliced in 8-byte slots of code for every
      VIC20-Byte (unfortunatly, that's not enough for a lot of 6502-Commands).
      An additional flag-byte is needed for every VIC20-RAM-byte.
 
- It's *not* faster than a normal interpreter:
      Programs usually run about 4 to 5 times longer on the Atari.
      This sounds very bad, but it is not. A lot of time is needed for
      updating the display (about 40% of the time is needed when simulating
      the colors on the Monochrom-Monitor) and for interrupts. Since I didn't
      change a single bit in the kernel, the original routine for decoding
      the key-matrix is running. On the other side, I had to encode the
      key-events of the Atari to let that routine work correct.
 
I found out very early, that this is *not* the ultimate emulation. But I
continued working on it, until my favorite ROM-Modules of the VIC20, the
games 'AVENGERS' and 'STAR BATTLE', where running. As they were made in the
early days of the VIC20, their 'CPU'-usage is not too high and they can be
emulated nearly in real-time. Fortunatly they use the timers to 'sleep' and
not some strange loops.
 
 
Now I've got a problem: The Copyrights.
I wrote my program just for fun (although I though it's a great invention).
Of course, I would allow to copy it freely. But you can't do anything
without the copy of the VIC20-ROMS and some game-modules (you can get them
nearly as gifts, if you still find them in a store).
 
The question is:
        - Am I allowed to distribute these files with my program ?
        - If not:  Am I allowed to copy these files at least to owners
                   of a VIC20, as they also could have transferred them
                   to the Atari on their own ?
 
Is there a 'yes'-answer anywhere ?
 
--
 
Helmut Hoenig, University of Kaiserslautern, Germany.
hoenig@informatik.uni-kl.de
 
------------------------------
 
Date: 22 Nov 89 16:08:37 GMT
From: sdcc6!sdcc13!pa1329@ucsd.edu  (pa1329)
Subject: Blitter disappointment (was: Time to create comp.sys.atari.flames)
 
In article <1261@atha.AthabascaU.CA> rwa@cs.AthabascaU.CA (Ross Alexander)
 writes:
>For what it's worth:  I have a blitter.  It's $75 down the toilet.
>The speedup it provides is _very_ marginal ( < 25% ), and affects
>only a few operations (essentailly, large blits).  QuikST and the
>TOS 1.4 upgrade are much more cost effective.  When I get home
>tonight I'll try to post some benchmark numbers.
>       Ross
 
 
 
 
 
Hmmm,.  I wonder why is the Atari blitter so ineffective.  Its
speed is no where comparable to the Amiga's blitter.   Why is the
difference?
 
------------------------------
 
Date: 23 Nov 89 04:34:23 GMT
From: uhccux!munnari.oz.au!murtoa.cs.mu.oz.au!viccol!timcc@ames.arc.nasa.gov
 (Tim Cook)
Subject: Experience with Toshiba 3 1/2 inch double sided drives?
 
Before I go out and buy one,
 
Has anyone out there got any first-hand horror stories on Toshiba 3 1/2 "
double sided drive mechanisms?  I am told they are "very reliable", but
then it was the person who would be selling me one who said that.
 
This would be a mechanism suitable for replacing an SF354 mechanism (single
sided).
 
I was offered a 6 month warranty if I installed the mechanism (into my own
modified SF354 case) myself, or a 12 month warranty if it was installed by
the dealer.  Are these values reasonable?  I'm looking at A$200 for DIY,
A$250 for dealer installed and 12 month warranty, or A$220 for DIY and 12
month warranty (presumably after the dealer has ratified the installation).
 
The Australian dollar currently buys about 77 US cents.
 
Any info appreciated.
 
--
Tim Cook     Systems Administrator, Victoria College Computer Services
 
parrot - n.  An animal that has the ability to imitate man, but not the
             intelligence to refrain from doing so.
 
------------------------------
 
Date: 22 Nov 89 04:58:00 GMT
From: att!chinet!saj@ucbvax.Berkeley.EDU  (Stephen Jacobs)
Subject: Gadgets by Small - Possible new '030 add-on board!
 
In article <529@kunivv1.sci.kun.nl> ge@kunivv1.sci.kun.nl (Ge' Weijers) writes:
>dnewton@carroll1.UUCP (Dave 'Post No Nicknames' Newton) writes:
>
>>   You mean... my ST isn't an 8-MIPS machine?  Oh no.  Sadness.
>
>It's not even a 1-MIPS (VAX/780-MIPS!) machine. It's on the same level
>as a VAX/750, at 0.7 MIPS or so.
 
On the other hand, the main computing resource at the laboratory where I work
(food R&D, but what the hey) was a VAX 11/750 for several years.  And I got a
LOT of mileage out of casually mentioning to the real computer people that my
ST acted a lot like their monster, except that since it was single user...
                                        Steve J.
 
------------------------------
 
Date: 21 Nov 89 23:43:58 GMT
From: hpda!hpcuhb!hp-ses!hpdml93!rona@ucbvax.Berkeley.EDU  (Ron Abramson)
Subject: Hard Drive Woes: HELP!
 
Dylan Yolles
 
>One of my hard drive partitions is turning into spaghetti. By that I mean
>that when I attempt to write a lot of stuff to it (maybe 2 megs) the new
>files are severely corrupted, the directory looks funny, the computer
>crashes, and so on. I believe that the drive can't write to certain
>sectors (I recently noticed a <write fail> message from the ICD utilities).
>What should I do?
 
Step 1: Back up as much of your data as you can WHILE YOU STILL CAN.
 
Step 2: Relax in the pleasant knowledge that your data is safe.
 
After steps 1 and 2, I would ZERO the partition.  This feature is avail-
able in the ICD utilities.  Zeroing the partition will erase the direc-
tory and may solve your problem.  What caused the problem in the first
place, is anybody's guess at this point.  Maybe it is the 40 folder
limit, but it could be hardware too.
 
Good Luck!
Ron Abramson
 
#include disclamer
 
------------------------------
 
Date: 21 Nov 89 16:35:06 GMT
From: davidli@UMN-CS.CS.UMN.EDU  (Dave Meile)
Subject: Vapourware!!!
 
In article <24310@cup.portal.com> Bob_BobR_Retelle@cup.portal.com writes:
>David Meile says a lot of uninformed stuff about Atari history...
 
Well, actually, none of it was "uninformed".  You might think I don't have
the "whole story", but your use of the term is deragatory in this particular
case.  And the last name is Paschall-Zimbel, although the account name is
still the one before my recent marriage.
 
>If you were involved with any of the online services where Neil Harris
>held court, or followed Atari Corp happenings in the media, you'd have been
>able to follow this discussion intelligently.
 
Yes, I was around on GEnie back in the good old days of 1986.  No, I don't
remember reading anything which was labelled "OFFICAL PROMISE" from Neil
Harris.  I sure hope you kept copies of each and every posting -- and if
you really want to be believed on this point, POST THE COPIES.  Same goes for
"Official Promises" made by any of the Tramiels in response to phone-in
questions -- if it isn't written up in a press release, with specs and
ordering information, it isn't "official" ... off-the-cuff remarks
notwithstanding.
 
>I'd still like to see what would happen if the proper Federal agencies
>became involved in this scam...
 
If you believe that there were criminal actions worth looking into, quit
posting this drivel, take your evidence directly to the Attorney General of
the State of California and sit back fat and happy.  Otherwise, I'd suggest
you drop the term "scam".
 
-- David Paschall-Zimbel
 
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End of INFO-ATARI16 Digest V89 Issue #692
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