Where does a router store its IOS in the long term?

A router stores its iOS (Internetwork Operating System) in non-volatile memory, typically in Flash memory. This allows the iOS to persist even when the router is powered off or restarted. The configuration files, which define how the router operates, can also be stored in NVRAM (Non-Volatile Random Access Memory) or Flash, depending on the setup. This ensures that the router can boot up with the correct operating system and settings.