Emulation is the process of reproducing the behavior of one system on another platform, often by software or programmable hardware. The goal is not to copy the original hardware part for part, but to make the target system behave close enough that programs, protocols, or peripherals work as expected. In retrocomputing, emulation can recreate old CPUs, memory maps, and devices; in a security lab, it can also model routers, phones, malware targets, or industrial controllers without using the real equipment.
In cyber security, emulation matters because it creates a safe, controllable stand-in for testing and analysis. Defenders use it to study malware, inspect suspicious disk images, and validate patches against legacy software. Attackers may abuse emulation to hide payloads, detect sandboxes, or run code only when the environment looks authentic. The main limits are fidelity and trust: if timing, device behavior, or input handling differ from the original, results can be misleading, so provenance and isolation still matter.