Altirra vs Javatari

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.

Javatari is a free Atari 2600 emulator designed for the Web. Users can load cartridges in a browser, with ROMs opened from local storage, iCloud, Google Drive, Dropbox or web links. It runs in browsers tested with Chrome, Firefox and Safari, and can be installed as a WebApp on iOS, Android or desktop for offline play. Savestates can be exported and shared. Playback controls include adjustable speed, pause and frame-by-frame advance; display tools include resizing, fullscreen, screen capture and debug modes. Customizable joysticks, joykeys and touch controllers are available, with haptic feedback on mobile. NetPlay lets multiple users connect to and control one virtual console over the internet, although it does not work on Apple iOS because required WebRTC technologies are unavailable there. Performance depends on network quality. A JavaScript API supports ROM loading and console control, and games can be embedded in webpages or launched with a Javatari page link. The project repository identifies the software as licensed under AGPL-3.0.