Note that since core options override the emulator's own config file, but Retroarch doesn't cover all the sub-options, you can set different versions of BASIC or different BIOSes for the supported systems via the emulator menuĪtari OS The Atari 400 and 800 were announced in December 1978, though they didn't actually start shipping until late in 1979.

In lr-atari800, Retroarch has these choices within the Core Option System: 400/800 (OS B), 800XL (64K), 130XE (128K) and 5200.

However, I really wanted an emulator that could keep up with all of the features of the Atari800 emulator, including full cartridge and machine support, hard drives, etc

Derek Ledbetter has a good port of Atari800 for OS9 and Carbon on OS X.

At the same time, it is still possible to compile a version of Atari800 without any OS ROMs built in, by means of the -disable-altirra_bio

to run Atari800 without providing OS ROMs now have an option of using the built-in Altirra OS-es, which are compatible with much more Atari software than EmuOS.

Atari 5200 emulator mac os x