What is the main function of a CMOS storage?

The main function of CMOS (Complementary Metal-Oxide-Semiconductor) storage is to retain essential system settings and configuration data, such as date, time, and hardware settings, even when the computer is powered off. This storage is powered by a small battery, allowing it to maintain information without needing a constant power supply. It is crucial for the BiOS settings in computers to ensure proper boot and hardware functionality.