Gemulator II/emulator/commerical

From: Bruce D. Nelson (aa789@cleveland.Freenet.Edu)
Date: 06/01/93-11:49:08 AM Z

From: aa789@cleveland.Freenet.Edu (Bruce D. Nelson)
Subject: Gemulator II/emulator/commerical
Date: Tue Jun  1 11:49:08 1993

RUN ST Software on your IBM CLONE - fact or fiction
Article By Don Liscombe
(from Z*net 9306)

Gemulator Report - 5 months after release - Software version 2.10.  A
hardware/software combination that allows you to run Atari ST software.
My evaluation is being performed on a 486-50DX EISA machine, with a
Diamond Speedstar 24X, and using a Microsoft serial mouse.

General information:

Gemulator consists of 2 parts, one being an 8 bit card which holds the
TOS roms and is sold by PMC, and the 68000 emulator software comes with
the package (Revision 1.0 - Unregistered). Darek Mihocka, of Branch
Always Software, is selling the commercial Gemulator software for
$59.95.  Software updates beyond this point, are $15, according to an
older readme file.  The software loads in and allows you to select
items, such as INSTALL (a specific TOS version), BOTH (floppies), SWAP
(A: and B: drives), FULLSCREEN or WINDOW mouse control, COLOR or MONO,
QUICK (screen redraws for some applications), SPEED (test), I486 for
speed enhancements with a 486 CPU, STATUS to report current settings,
and QUIT to DOS mode.  Depressing the F11 key, will bring you back to
the Gemulator menu, while the F12 key will reboot your "ST".


The TOS ROM board is easily installed, in any ISA/EISA slot which works
with an 8 bit card.  The circuit board is of a quality design, and all
chips on the board are socketed.  The board as shipped, comes with Atari
TOS 2.06, and sockets exist for up to a total of 4 versions of TOS.  (A
total of 8 sockets are on the board for ROMS, 2 of them used by TOS
2.06) Written documentation is rather limited, and should you wish to
add additional TOS ROMS to the circuit board, the picture they give
displaying the position of the 6 chip rom set, is barely legible.  They
would have been far better off with a hand drawing, than a poor scan of
a photo.  Since my package was an original release, perhaps it has been
upgraded since then.  Detailed instructions are now given on how to
modify the circuit board to accept the TOS 1.4 - 2 chip set in the
current readme file on the Gemulator disk.

Look & Feel:

The display quality is excellent, both from DOS mode, and from a Window.
GEM screen redraws are slow, and need the assist of a screen accelerator
such as Warp 9 or Turbo ST, just the same way a stock ST does.  Running
Gemulator in a Window, makes the screen display crawl (no one said
running a graphics display in a Window would be fast) using Windows 3.1,
but it seemed to run a bit faster in an OS/2 Dos Window (sorry


With version 2.10 of the software, a 4 meg PC can now emulate a 1 meg
Atari ST, quite an improvement over the original version.  The software
will work with either 3.5" or 5.25" floppy drives, and disk I/O speed
seems about normal.  A 486 33Mhz is required for overall ST 100% speed.


Gemulator emulates the ST quite well.  Although Darek has some touchups
to put on some routines, he has done an excellent job so far, in getting
this emulator up and running ST software.  It works well with OS/2, as
long as you remember to adjust your DOS settings to give Gemulator the
5.25 megs of XMS memory it wants to load into.  As PCs get faster and
faster, Gemulator will be able to run your ST software faster as well.


With older versions of Gemulator, when you ran Gemulator in a window,
(in either Windows 3.1 or OS/2) the Atari mouse pointer (which becomes
active when you move the Windows mouse pointer inside the DOS window),
drifted away from the windows mouse pointer.  This becomes very
annoying, having 2 different pointing devices on the screen, both moving
as you move the mouse, apart from each other.  The good news is, that
you can use the Atari mouse alternate keys to align the two pointers
back together (ALT-arrow keys).  Unfortunately, for my system, they were
not long drifting apart.

Version 2.10 has done some adjustments on the to slow down the mouse,
and in DOS mode, it now responds almost exactly like an ST, but I can no
longer get Gemulator to run at all, using the WINDOWS mouse driver, it
just locks up solid, in either Windows 3.1 or OS/2.


A patch program for Gemulator,now allows you run in 640X480 16 color
mode, by taking advantage of the VGA card.  This should allow you to run
software written for TT med rez, 1280X960 moniterm mode, and well
behaved GEM programs.


What is allowed you in version 1.0, is the ability to read only, the
first 32 megabytes of your C partition.  Version 2.10 will allow you to
read and write to the first 32 megs of any PC hard drive, and also allow
you a single 32 meg file which simulates another hard drive, and it is
referred to as a virtual hard drive.  This file can be placed on a
network or stacker(compressed) drive, only 1 file is allowed.  This is a
great improvement from previous versions, but still lacks the ability to
fully implement reading and writing on your PC hard drives.  Here are
some captures from Gemulator doc files:


"Our solution to this problem is to write a custom Atari ST hard disk
driver that understands the large DOS partitions.  A future update of
Gemulator will contain this driver built-in to it, eliminating the need
for even using AHDI.PRG or SUPBOOT.PRG.  The custom driver will also
allow any hard disk partition to be accessed, as well as the PC's RAM
disks, CD-ROM, and network drives."

"Similar drivers will also be written to allow Gemulator to work under
other operating systems, such as OS/2 and Windows NT.  These newer
operating systems also use entirely different hard disk formats that
makes Gemulator incompatible with them at this time."


Hard Disk Support

"We're happy to say that hard disk writes are now enabled.  BUT USE THIS
FEATURE WITH EXTREME CAUTION!!! We are almost finished writing
Gemulator's custom hard disk driver which eliminates the 32 megabyte
partition limit in existing hard disk drivers.  This fixed driver will
be included in the Gemulator 2.1 upgrade, and that disk will be mailed
to you automatically and free of charge."

"Again, our replacement hard disk driver should be finished in December
and we'll ship it out to you either then or after the holidays. The new
driver also gives access to other MS-DOS disk drives that are not hard
disks, i.e. MS-DOS RAM disks, network drives, and CD-ROM drives.  The
existing Atari hard disk drivers simply have no concept of these

Supposedly, this version (2.10) was to have the 32 megabyte partition
limit removed from the hard drives, add support for CDRoms and ramdisk
devices, and remove the need for a hard drive boot program in the auto
folder, but this version would appear to have a single 32 meg file added
with directory hidden inside, with files inaccessible to DOS, with no
apparent support for CDRoms, ramdisks, or extended partitions.  No
mention is made of an update driver, cdrom, etc, in the new doc file,
which is quite a disappointment.  You still require a hard drive boot
program to access any hard drive, whether it be one less than 32 megs in
partition size, or this new 'virtual' hard drive.


Although Flash is listed as a program you can run on your PC in both
pamphlets handed out at product shows, and PMC advertisements, there is
no support for the RS232 port at all.  The current readme file on the
version 2.10 disk, indicates that a revision is planned to include RS232


With the initial version of Gemulator, GFA Basic(V3.5,3.6) had problems
with the screen locking up.  With the new version, all problems appear
to have been corrected, and GFA Basic works quite well.


Gemulator does not read most copy protected disks.  Considering the two
computers use completed different floppy controllers, it is doubtful
that protected disk support will be added.  It was interesting to see
Gemulator load in Dungeon Master to the introduction, but then the mouse
got very confused, and it would not recognize my disk as the original
disk after checking for copy protection.  Flight Simulator loaded up,
and the screen displays looked fine, but the mouse up/down was inverted,
and the keys for the throttle would not respond at all.

It would appear there are still a fair number of problems to resolve on
the keyboard/mouse routines, before Gemulator will handle the larger
portion of games(that it can get by the copy protection on).  Some games
which would load in, and use VBIs to have smooth scrolling, seemed to
flicker excessively.  This was also evident on the load in sequence of
Gunship by Microprose.


Although Gemulator supports read and write access to the IBM high
density 5.25" and 3.5" drives, you are only able to format your floppies
in 360K and 720K from the Atari format disk screen.  TOS 2.06 has
support for high and low density floppies, so perhaps this will be added
in the future.

WHAT IS NOT EMULATED (above the hard drive & RS232 restrictions)

Sound, Midi, joysticks & the blitter chip are not emulated.  According
to the text file on the disk, over the next year, support will be added
for the sound, midi, and the joystick.  As I recollect, Darek was
working on the blitter emulation to speed things up at the Toronto Atari
Computer Exhibition(spring 1992), but I see no mention of it in any of
the information I have.


Gemulator has been shipping since mid-September 92, and Darek has done
some excellent work on getting the initial problems removed, and the
speed of the program increased.  The windows mouse driver should not be
a problem to fix, as it was working previously.  With joystick, MIDI,
and RS232 support coming shortly, the only downfall I can really note
with the product, is the hard drive/CDROM support limitations.  Perhaps
it will take a driver (SYS) file in the config.sys at bootup to resolve
the 'sharing' PC drives problem, but it must be done to make Gemulator
a product that meets its' advertized features, and fully functional.

BIO: Don Liscombe is the SysOp of The Brewery BBS  - AtariNet 51:5/0 -
Fnet node 66 416-683-3089 HST Dual 14.4 - Supporting the Atari ST & IBM

Gemulator is available from
Purple Mountain Computers, Inc.
15600 NE 8th St.  Suite A3-412
Bellevue, WA 98008
voice 206-747-1519

Gemulator information can be obtained either from PMC, or

Branch Always Software(Darek Mihocka)
14150 NE 20th St.  Suite 302
Bellevue, WA  98007
voice/recording 206-885-5893

OS/2 is copyrighted/trademarked by IBM Corp.
Windows is copyrighted/trademarked by Microsoft Corp.

Return to message index