emulj

Emulj is a modular open-source emulation framework designed to recreate legacy computing environments on contemporary hardware. It provides accurate timing, memory models, and I/O emulation through architecture-specific backends while offering a stable API for front-end tools and automation scripts.

The name combines emulate with a nod to Java-inspired heritage; development began in the early 2010s by a community of digital preservationists and hobbyists. The project is released under a permissive license and has grown through contributions from researchers, educators, and retro-computing enthusiasts.

Emulj's architecture centers on a portable core that coordinates timing, memory mapping, and device I/O. Backend modules implement individual CPUs and hardware subsystems. A plugin system allows adding new architectures without altering the core. Scripting interfaces in Lua or Python enable automation and testing.

Key features include cycle-accurate emulation modes, dynamic translation, optional JIT acceleration, and robust snapshot and disk-image support. It supports a range of architectures, including vintage 8- and 16-bit CPUs and common peripherals. The project emphasizes reproducibility, documentation, and accessible debugging tools.

Typical uses include digital preservation of abandonware, academic demonstrations of computer architecture, and development and testing of software for legacy systems. While Emulj prioritizes fidelity, performance varies with backend maturity, and users should consider licensing and hardware compatibility when selecting backends.

See also QEMU, DOSBox, PCem, and MAME.