GEMulator
The Atari 8-bit/ST Computer Emulator

GEMulator runs Atari ST software in real time using only a 486/33 computer.  Due to the much faster speed of Pentium based computers, GEMulator typically runs faster than Falcon and Atari TT computers. On a 300 MHz Pentium II based computer GEMulator runs over 25 times faster than the original Atari ST, making it faster than any of the 68030, 68040, or 68060 Atari clones that have been appearing in the US from Germany.

        
Screen Captures of GEMulator running under Windows 95
Click on images to enlarge

Other than minor differences in speed and the operating system you run them on, all versions of GEMulator share a common set of features:

• 512K to 8M of Atari ST memory

• ST Low 320x200 16-color graphics

• ST Medium 640x200 4-color graphics

• ST High 640x400 monochrome graphics

• TT Medium 640x480 16-color graphics

• Modem, printer, and sound support

• 720K and 1.44M floppy disk support

• Hard disk support

• Mouse and keyboard support

• Support for TOS 1.0, TOS 1.2, TOS 1.4, TOS 2.06, and MagiC

• Support for 64K Macintosh ROMs using the Magic Sac emulator
  
  

With all versions of GEMulator, you can run most of the major desktop publishing, graphics, word processing, and finance software written for Atari ST computers.  For example, you can edit and run your GFA Basic programs, run Pagestream and print your documents, run Calamus SL and print your documents, query your Data Manager ST databases, write documents with Word Writer ST, draw graphics with Degas Elite, run some old Macintosh software using Magic Sac, and most other things you do on an Atari ST computer.

GEMulator 98 versions 4.81 and higher add additional capabilities that go beyond those of the MS-DOS version:

• Faster emulation speed, optimized for Pentium MMX and Pentium II processors

• STE emulation, support for STE-only TOS (TOS 1.6, TOS 1.62, and TOS 2.05)

• 800x600, 1024x768, 1280x1024, and 1600x1200 video modes

• Full screen and windowed modes of operation

• up to 14 megabytes of Atari ST memory

• Built-in 68000 debugger and third party debugger support

• Support for very large hard disk partitions, CD-ROMs, and network drives

• Easy-to-use point and click configuration
  
  

GEMulator is written almost entirely in 32-bit assembly langauge.  It is an extremely fast emulator requiring only a 33 Mhz 486 to operate at the full speed of an Atari ST, and a 75 Mhz Pentium to emulate the full speed of a TT030.  GEMulator is a 68000
emulator that also emulates the many custom chips of the Atari ST/STE computers (such as the MFP and video chips).  This allows it to run most Atari software, including programs that bypass the GEM operating system and those that write directly to hardware or to screen memory.

The 68000 emulation is so complete that 68000 debuggers run just fine on GEMulator.   The IPL levels, trace bit, supervisor and user modes are all emulated.

GEMulator's only limitations are that copy protected floppy disks are not supported, MIDI ports are not supported, and timing dependent software is not supported. For example, programs such as Spectrum 512 which run only on 8 MHz Atari ST models, but not on 16MHz STE or 32 MHz TT models will not run on GEMulator either.  This is because GEMulator typically runs much faster than the standard 8 MHz speed of an ST.

GEMulator 98 uses a combination of plug-in hardware card, TOS ROMs, and emulation software.

The hardware is an 8-bit ISA card that includes the Atari ST or STE TOS ROMs.  The card plugs into any empty ISA slot in your PC or docking station.  One or more sets of Atari ST or STE TOS ROM chips must be plugged in to the card to operate, since it is these TOS ROMs that contain the Atari's GEM operating system, which in turn runs your Atari software.

Up to four 2-chip sets of TOS ROMs may be plugged in to one GEMulator card, or a combination of one 2-chip and one 6-chip set of ROMS as shown in the picture on the left.  You may also plug in a 2-chip set of 64K Mac ROMs which can be found in old Magic Sac and Spectre cartridges.

GEMulator has been heavily tested on a variety of microprocessors ranging from a 16 MHz 386SX to a 200 MHz Pentium Pro.  We have found no problems on any of the Intel 386, 486, or Pentium processors.  Our testing and feedback from several users has indicated that GEMulator will have problems on TI 486, AMD 486, and Nexgen 586 processors. These are all "clone" 486 processors, so at this time we recommend running GEMulator only on genuine Intel microprocessors.  The AMD K6 chip appears to run GEMulator just fine.

If you plan to supply your own TOS ROMs instead of purchasing GEMulator already preloaded with TOS ROMs, start looking around for Atari ST, STE, or TT ROMs to use in the GEMulator card. The ROM card can accept all types of Atari ROMs from the 520ST to the Atari TT.

The TOS ROMs come in sets of 2, 4, and 6 chips, in either 28-pin or 32-pin packages.   If you don't have loose ROMs but have an Atari computer, unscrew the cover from your Atari and find the ROMs on the motherboard.  GEMulator takes advantage of the higher graphics resolutions available in your PC's video card.  In addition to emulating the 3 standard Atari ST screen resolutions (320x200 in 16 colors, 640x200 in 4 colors, and 640x400 monochrome)  GEMulator also supports 640x480, 800x600, 1024x768, and 1280x1024 in monochrome and 16-color modes. 

Unlike a real Atari computer that would require up to 4 separate monitors to accomplish this, most PCs can display all these resolutions on a single SuperVGA monitor.

GEMulator can emulate a 520ST, a Mega ST 4, or a MegaSTE with up to 14 megabytes of memory (8 megabytes on GEMulator Classic for MS-DOS). The amount of memory being emulated can be set at 512K, 1 meg, 2 meg, 4 meg, 8 meg, or 14 meg, and can be changed at any time while running GEMulator.

Access your Atari single sided 360K, double sided 720K, and high density 1.44M floppy disks, as well as 800K disks and boot disks. GEMulator can even read those old TOS 1.0 formatted floppy disks that PCs normally can't read.   Note: Copy protected floppy disks are not supported. Windows 3.1 and Windows NT do not support the TOS 1.0 formatted disks.

GEMulator 98 also automatically accesses all the hard disk partitions and CD-ROM drives connected to your PC.  Earlier versions of GEMulator required setting up separate Atari ST hard disk partitions, and while this is still an option it is no longer required.   GEMulator automatically takes care of large hard disk partitions, Stacker and DoubleSpace partitions, and other hard disk formats that TOS did not originally support.

That's right: GEMulator 98 eliminates GEM's 32 megabyte partition size limit!

As mentioned earlier, GEMulator is not only a complete 68000 emulator, but it also emulates all of the special hardware chips used inside Atari ST computers. This includes the video chip, so that programs which write directly to screen memory run just fine. NVDI 4, Warp 9, Quick ST 3, Turbo ST, and other screen accelerators are fully supported.

Atari programs can access any printer or modem that Windows supports. You can switch between them on the fly, by specifying which COM port and which LPT port to use as the Atari modem and printer ports.  On GEMulator 96, modem baud rates beyond 19200 baud are also supported, including 28800, 38400, 57600, and 115200 baud. Note: GEMulator 96 does not support the modem when running on Windows 3.1 or Windows For Workgroups.

GEMulator is a commerial product.
It cannot be downloaded here.
Visit the GEMulator home page for more product
specifications, and ordering information.

Go to the GEMulator homepage