Fresh Fish 8/FreshFishVol8-CD1.bin/useful/reviews/hardware/emulation/atonce

Internet Message Format | 1992-05-06 | 21KB

From: [e-mail] (Jason L. Tibbitts III)
Organization: Blob Shop Programmers
Subject: REVIEW: ATonce
Keywords: emulation, IBM, AT, hardware
Distribution: world
Newsgroups: comp.sys.amiga.reviews
Followup-To: comp.sys.amiga.emulations
Reply-To: [e-mail] (Todd Lowe)

The ATonce is a hardware IBM AT emulator similar to the AT bridgeboard,
except it is designed for the Amiga 500 instead of the Amiga 2000. It
performs the emulation quite well, but problems with its setup software
and possible problems with various Amiga configurations detract from its
usefulness except on a bare-bones A500 system.


Lately a lot of people have been wondering about the ATonce 80286
emulator for the Amiga 500.  Last week I had the opportunity to test
one of these and unfortunately did not have much success.  Here I will
explain what the thing is (if you don't know), how it's supposed to work,
and the problems I had.  All testing was done on a Revision 5 Amiga 500
with the new Agnus, 1 meg chip ram, 42ms 48Meg Seagate st157-n hard drive,
Trumpcard controller and 2 meg fast ram. I also have both AmigaDos 1.3 and
2.0, but since 2.0 is loaded to ram it's pointers seem to be reset when
the ATonce is used. For this reason testing was done using Kickstart
and Workbench 1.3. The product was tried both with and without the A500
expansion hardware and on a 2000, but the latter two configurations were
tried only briefly while first was used for about a week.

[Ed. Note:  If you have used the ATonce on other configurations, or have
any other information which you wish to add, please send mail to
[e-mail] with your experiences.]

At the end of this review are benchmarks and test results obtained
with Norton Utilities and CheckIt.

----------------------------------------------------------------------

The ATonce is an 80286 AT emulator from a German company 'Vortex'.

Their address:

 Falterstrasse 51-53, D-7101 Flien bei Heilbronn, Germany.
 phone : [phone]
 e-mail: 100016,[e-mail]

 I tested a unit from:
 Computers Plus,
 Ralph Doncaster,  [e-mail]

It is a very small board containing a Motorola 68000.  This is important
because many Amigas have third party 68000's and Vortex claims they need
the stability of a real one.  (I don't know if this is so, but at least
it is easier to install; you simply remove the existing 68000 and plug in
the card)  The board also contains an Intel 80286 and a large custom gate
array containing the BIOS and other custom circuitry.  Along with this is
a special "double socket" to put under the Gary chip and initialization
and setup software.

Once I had the ATonce I immediately installed it following Vortex's manual.
This caused some problems.  I had the CPU card and the Gary module installed
correctly, and I'd run the setup program and told it to use default settings,
but I could not get the program to work.  When you start the initialization
software it normally sets some pointers to the ATonce code, then reboots
the Amiga.  At this point you get both an Amiga startup screen and a
standard MS-DOS screen complete with memory and BIOS test.  On my
system I was losing the memory required for the ATonce, but was not getting
that MS-DOS screen.  I tried with and without my HD, expanded memory,
even tried an old Agnus, but no luck.  It turned out that on my system
it only works WITHOUT the Gary module.  The manual says that the Gary module
may cause problems finding an A590 HD, but apparently causes problems on
older A500's as well.  I should mention here that the purpose of the Gary
module is to avoid timing differences between internal and external
memory expansion in the 500, and is therefore unnecessary in a 2000.
The manual says that it will not work with the 2000, but someone else here
tried it in his and it seemed to work about the same as on my 500. (As you
will see this should be read FLAKY.)  On the 2000 ATonce would initialize
about half of the time and would run MS-DOS software once it was up.
The extent of our tests was to boot DOS and exit so perhaps someone else
(or maybe myself if I get time) could do more in depth tests on the 2000.

[Ed. Note: If anyone has done this, please sent mail to [e-mail].]

While attempting to get the ATonce working the first time I noticed that
the manual mentioned problems with older revision motherboards.  There
are two files on the program disk that have the extension .dsg.  Only one
of these is used by the ATonce, but apparently they are modifications
for different revision mother boards.  The files are named "atonce.dsg"
and "other.dsg".  The manual says something to the effect of:

    "If your motherboard is an older revision than 6A you
    may need to rename other.dsg to atonce.dsg to obtain full
    performance from your ATonce. Do NOT ever use the file
    other.dsg on a revision older than 6A."

Yes, I know this contradicts itself, but it is in the manual (not
a direct quote as I have returned the product, but close enough).
To confuse things even more their Erratum listed the passage as:

    "If your motherboard is newer than revision 5 you may need
    to rename other.dsg to atonce.dsg to obtain full performance.
    NEVER use the file other.dsg on a revision newer than 5."

Again this is not a direct quote, but it is just as confusing and explains
the problem.  Not knowing which to use I tried with both and found
they both work, but other.dsg was faster according to Norton's SI.

Now at this point I have the ATonce program loading from my HD, but
DOS booting from floppy and have only run MS-DOS and SI.

The biggest problems start when trying to install ATonce so that MS-DOS
can use the Amiga HD.  ATonce allows for HD support as either a file
on an AmigaDos partition or a full MS-DOS partition.  First I tried
to create a file.  The manual and setup program are straight forward.
You select 'Hard Drive' and tell it what you want following prompts AND
the manual.  The format for file is:
    HD:path/filename,first_dos_track,last_dos_track
with 50 tracks being about 5 megs.  For a partition you simply give the
partition name (it must be a mounted device).

After creating a file the right size I ran ATonce.  No luck.  It used
memory when I rebooted, but didn't initialize the card.  The next time
I rebooted, AmigaDos couldn't validate the hard drive containing the
partition file.  I managed to validate the drive with AmigaDos 2.0 (not
sure why 1.3 wouldn't) and the tried again after doing a cold boot.
This time the ATonce found the file and used it as C:.  I was able to
make this a boot partition using Zenith's PART program, format it, and
install Zenith Dos 3.30 plus.  I rebooted and tried again.  This
time the ATonce worked correctly, and even booted from the HD file.

Great, now it was working! WRONG!

Now every time I changed something in the ATonce configuration my HD
wouldn't validate.  Eventually it was beyond even FixDisk and was
reformatted.  Since I had to reformat I tried creating a MS-DOS partition
in addition to a file.  This did not go well either.  I could get the
partition recognized, but when I tried to format or partition it
the system would crash.  Amiga-Amiga-S is a hardware reset for the ATonce,
and even this did not work at this point.  (One thing I did like was
that it never crashed or even affected the Amiga side once it was running.
The setup and initialization programs often did, but MS-DOS didn't.)

OK, enough problems with the hardware.  Now I created a partition file
and formatted it and decided to test the thing's MS-DOS compatibility.
After great pains with disk drive being trashed I got ATonce working.
With my memory configuration (3 megs) I was able to get ONLY 640K base
and 512K extended.  This left over 1.5 megs for the Amiga Side, but
the way the ATonce software operates it couldn't access it.
My configuration is:
        $8c2    -  $7e7ff    : original chip ram
        $80000  -  $fffff    : extra 512K chip ram
        $280000 - $2fffff    : 1st Meg fast ram
        $380000 - $3fffff    : 2nd Meg fast ram

ATonce would let me use $80000-$fffff and either Meg of fast ram,