The Free (Atari) TOS (The Operating System) aka EmuTOS

The Atari TOS (The Operating System) was presented with the Atari ST series starting in 1985. Atari TOS was written by Digital Research’s GEM GUI running on top of GEM DOS. Atari’s TOS is usually run from ROM chips contained in the computer and it was an almost instant-running OS. Initially TOS booted off floppy disks in the very first series of Ataris STs, but with a ST series all ST models started shipping with the latest version of TOS in ROM. Picture you see is actually Emu TOS not Atari TOS.

So what is Emu TOS ?

EmuTOS is a Free operating system for computers based on Motorla 680×0 and ColdFire CPU’s with similar features and functionality as Atari TOS.
But it is FREE as there are no code written by Atari in EmuTOS, some parts originate from It is made from Digital Research’s GPLed original sources, while other parts have been developed from scratch.

EmuTOS can run on real hardware as a ROM replacement, as a bootable floppy, or as a program. Of course, it also runs happily on any Atari emulator(s) or REAL Hardware ST(efm), TT or Falcon.

As EmuTOS is Free Software it can be freely used and redistributed with emulators respecting the GPL licence. This allows users to run legacy third-party software on emulators without requiring copyrighted Atari ROMs, thereby avoiding legal issues.

The EmuTOS project started in 2001, and it is still being actively developed. It is distributed under the GNU General Public License, version 2 (GPLv2).

On 2020-09-02 we have release 1.0, download what are you waiting for 🙂

Link:The EmuTOS
Link:Download EmuTOS