¶ Technical data
- Manufacturer: Atari
- Year of release: 1985
- Operating system: TOS with the GEM graphical interface, in ROM
- CPU: Motorola 68000 @ 8 MHz
- RAM: 512 KB (520ST) up to 4 MB depending on the model
- Video: 320×200 in 16 colors, 640×200 in 4 colors, 640×400 monochrome
- Sound chip: Yamaha YM2149, 3 voices
- Media: 3"½ floppy disk
- Distinctive feature: built-in MIDI IN/OUT ports as standard
¶ Presentation
The Atari ST is a 16/32-bit home computer released by Atari in 1985 under Jack Tramiel, the former head of Commodore. The ST initials stand for "Sixteen/Thirty-two", referring to the 16-bit bus and 32-bit registers of the Motorola 68000. Its main selling point was value for money: a complete 68000 machine, monitor and floppy drive included, for a fraction of the price of a Macintosh.
The ST carries TOS, its operating system, and GEM, its windowed graphical interface, in ROM. Its most lasting peculiarity lies elsewhere: Atari fitted MIDI ports as standard, which made it the reference machine of music studios for a decade. Cubase and Notator, the ancestors of modern sequencers, were born on the Atari ST.
On the gaming side, the ST shared the late 1980s with the Amiga in a famous rivalry, most titles being released on both platforms. The range then grew: the Mega ST for office use, the STE in 1989 with its blitter and 8-bit stereo DMA sound, the Mega STE, then the high-end TT and Falcon machines in the early 1990s.
¶ Emulators
Emulator availability per board:
| Emulator | RPI3/RPI02W | RPI4/400 | RPI5/500 | OGA/OGS/RG351 | PC | RG353 |
|---|---|---|---|---|---|---|
| Libretro hatarib | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
| Libretro hatari | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
| Hatari | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
All three emulators derive from the same Hatari project. HatariB (libretro hatarib) is the default emulator on every board: it is the most recent and most complete libretro port. Libretro Hatari is the older core, kept as a fallback. Standalone Hatari is the native version, outside RetroArch, useful for advanced uses (virtual hard disks, full Hatari configuration). Netplay is not available on this system and RetroAchievements are not supported. CRT output is handled by both libretro cores.
A keyboard is mandatory on this system, and a mouse is strongly recommended. The ST boots into the GEM desktop, which is driven with the mouse, and a large share of the games (adventures, management, point & click) are designed for the mouse or expect precise keys. A pad is still recommended for action games, which use the joystick port.
¶ Automatic machine selection by folder
Recalbox infers the machine to emulate — and therefore the TOS to load — from the name of the folder holding the rom. Store your games in sub-folders so you do not have to set the machine game by game:
| Folder name | Emulated machine | BIOS loaded |
|---|---|---|
st, atari-st |
Atari ST | st.img |
megast, mega-st, atari-mega-st |
Atari Mega ST | st.img |
ste, atari-ste |
Atari STE | ste.img |
megaste, mega-ste, atari-mega-ste |
Atari Mega STE | megaste.img |
tt, atari-tt |
Atari TT | tt.img |
falcon, atari-falcon |
Atari Falcon | falcon.img |
With no recognised folder, the Atari ST is emulated. If the game path contains the word emutos, EmuTOS is loaded whatever the machine.
¶ BIOS
TOS is the operating system of the machine: without a TOS image, the emulator has nothing to boot. Put at least st.img in /recalbox/share/bios/atarist/, and add the other images if you play STE, TT or Falcon titles.
| File name | Description | MD5 | Emulators |
|---|---|---|---|
atarist/st.img |
TOS for Atari ST and Mega ST (mandatory) | — (many TOS versions accepted) | HatariB, Libretro Hatari, Hatari |
atarist/ste.img |
TOS for Atari STE (mandatory for STE games) | — (many versions accepted) | HatariB, Libretro Hatari, Hatari |
atarist/megaste.img |
TOS for Atari Mega STE (optional) | — (many versions accepted) | HatariB, Libretro Hatari, Hatari |
atarist/tt.img |
TOS for Atari TT (optional) | — (several versions accepted) | HatariB, Libretro Hatari, Hatari |
atarist/falcon.img |
TOS for Atari Falcon 30/40 (mandatory for Falcon games) | — (several versions accepted) | HatariB, Libretro Hatari, Hatari |
atarist/tos.img |
Generic TOS, used when the machine-specific image is missing | — (many versions accepted) | HatariB, Libretro Hatari, Hatari |
atarist/emutos.img |
EmuTOS, free and redistributable BIOS, compatible with 99 % of Atari machines | e2c861c588fca2d0cf6be3df3aaf05f2 | HatariB, Libretro Hatari, Hatari |
Place your BIOS files like this:
/recalbox/share/bios/atarist/
├── st.img
├── ste.img
├── megaste.img
├── tt.img
├── falcon.img
├── tos.img
└── emutos.img
The emulator looks for files in this order: first the image matching the detected machine (ste.img for an STE game, for instance), then atarist/tos.img, then tos.img at the root of /recalbox/share/bios/, and finally EmuTOS. A single file is therefore enough to boot, but each machine behaves better with its original TOS.
EmuTOS is the only BIOS in this list that is freely redistributable: it is the legal fallback when you own no TOS image. HatariB embeds an internal copy and therefore boots even when no file is present — but compatibility with commercial games is better with a real TOS.
¶ Roms
Put your games in:
/recalbox/share/roms/atarist/
Supported extensions per emulator:
| Emulator | Extensions |
|---|---|
| HatariB | .dim .ipf .m3u .msa .st .stx .zip .7z |
| Libretro Hatari | .dim .ipf .m3u .msa .st .stx .zip .7z |
| Hatari | .ctr .dim .ipf .msa .raw .st .stx |
A few landmarks about those formats:
.stis the most common floppy image,.msaand.dimare two other classic image formats;.stx(Pasti) and.ipfpreserve the physical protection of the original floppies: prefer them for protected commercial games;.zipand.7zarchives start without being extracted with both libretro cores.
For a game spread over several floppy disks, create a
.m3ufile listing the images in order, one per line, and start that.m3uwith a libretro core: disk swapping is then done from the emulator menu.
Also have a look at the Atari ST guide for game preparation, configuration and system-specific tips.