Altirra vs EMU7800

Altirra is a Windows emulator for 8-bit Atari computers, covering the Atari 400/800, 1200XL, 600/800XL, 130XE, XEGS and 5200. It provides cycle-exact handling of documented hardware and models undocumented behavior, including DMA timing and undocumented 6502 instructions. Supported files include ATR, ATX, ATZ, DCM, XFD, PRO, ARC, BAS, ROM, BIN, A52, CAS and SAP. Reimplemented operating-system, BASIC and handler ROMs are included, while real Atari ROM images can be supplied for compatibility. The emulator models memory and cartridge expansions, PBI devices, modems and 65C02/65C816 accelerators. Disk options include accelerated loading, realistic timing, sounds and drive CPU emulation. Its debugger offers source stepping, breakpoints, watchpoints, history and profiling. Recording, a cheat trainer, disk browsing and text copy/paste are also included. Altirra is free under GPL version 2 for Windows 7 or later.

EMU7800 is a free emulator for the Atari 7800 ProSystem and the backward-compatible Atari 2600 Video Computer System. It runs on Windows, Linux, and macOS and supports saved game states. The maker says it runs on Windows 11, and its Windows installer does not need administrator permission. Windows users can connect Stelladaptor, 2600-daptor, 2600-daptor II, and Xbox 360 controllers. Saved game state is kept in the user profile at %USERPROFILE%\.emu7800savedgames. The project lists Linux ARM and ARM64 targets using SDL3; Linux systems may need SDL3, SDL3 image, and SDL3 TTF installed. Its macOS x64 and ARM64 targets are described as experimental and untested. Building from source requires the .NET 10.0 SDK and Git. The project was originally completed in 2003 as a .NET programming exercise, is licensed under GPL-2.0, and is maintained as a non-commercial endeavor. The current release listed is v5.7.0.0, released December 31, 2025.