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A CMOS battery is a small, coin-shaped battery on a computer's motherboard that provides power to the CMOS chip, which stores crucial system settings like the date, time, hardware configuration, and BIOS settings even when the computer is off. It is also known as the RTC (Real-Time Clock) battery. When this battery dies, the system may lose its settings, leading to incorrect dates, boot problems, or forgotten passwords, and needs replacement to restore proper functionality.

What it Does

Stores System Information:

The CMOS battery powers the CMOS chip, a type of memory that holds essential configurations.

Maintains Real-Time Clock (RTC): It ensures the computer's clock continues to run, keeping track of the correct date and time when the computer is powered off.

Preserves BIOS Settings: The battery also retains the Basic Input/Output System (BIOS) settings, which are low-level instructions for how the computer hardware interacts.

Enables Quick Boot-up: By keeping these settings stored, it allows for faster startup and ensures your operating system loads correctly.