Atari TOS runs on a Sega Mega CD — an open-source port brings retro OS to a 16-bit console

A developer known as 1d4r3k has successfully ported the Atari TOS operating system to the Sega Mega CD, a 16-bit console from the early 1990s. Instead of the original TOS, the port uses EmuTOS, an open-source drop-in replacement that is fully compatible with the original system.

The current implementation supports a serial keyboard device, a printer, and sound output. The OS mounts the CD or cartridge from which it booted, a RAM disk, internal backup RAM, and cartridge save RAM. The tip email accompanying the project also mentions that some work has been done porting GEOS to the platform, which could eventually lead to the GEOS software suite being made available on the Sega Mega CD.

No images or videos of the system in operation have been released yet, so there is no visual confirmation of the port working. However, the developer states that trying it is straightforward: users can either burn an ISO image to a CD or flash a cartridge if they have the original hardware. It remains uncertain whether the port will be practical given the Sega Mega CD's limited specifications — the console features a 12.5 MHz Motorola 68000 CPU and 6 MB of RAM in total. But the developer notes that TOS originally ran on Atari ST computers with as little as 512 KB of RAM, suggesting the port might be viable for basic tasks.

This project is part of a broader trend of running alternative operating systems on classic 16-bit consoles. Earlier, Linux was successfully ported to the Sega Mega Drive/Genesis, demonstrating the potential of these aging platforms. The Atari TOS port, while still in early stages, opens up the possibility of using a console as a retro computing environment, potentially running productivity software or games from the Atari ecosystem.