Emulators

An emulator is a software program or hardware device that enables a host computer to run software designed for a different system. Emulation reproduces the guest’s hardware behavior in software, translating CPU instructions, memory architecture, and peripheral interfaces so that programs written for the guest can operate on the host. Emulation may also simulate timing to preserve the look and feel of the original hardware. Techniques used include interpretation, which translates instructions on the fly, and dynamic translation (just-in-time compilation), which converts blocks of guest code into host code for faster execution.

System emulators aim to recreate an entire guest computer, including CPU, memory, and I/O devices, while application-level emulators focus on translating a specific program or runtime environment. Examples of well-known emulators include Dolphin for GameCube and Wii, PCSX2 for PlayStation 2, MAME for arcade hardware, and DOSBox for MS-DOS. General-purpose system emulators such as QEMU and Bochs can emulate different architectures, supporting cross-architecture development and software preservation.

Emulation is used for software preservation, retro gaming, hardware testing, and cross-platform development. Key challenges include achieving accurate timing and peripheral compatibility, which can impact emulator speed and fidelity. Legal and ethical considerations accompany the use of copyrighted firmware, game ROMs, and BIOS images; distributing or using certain dumps may require licenses and may be restricted by copyright law. Despite these issues, emulation provides access to legacy software and hardware concepts that would otherwise be unavailable on modern systems.