What is the primary function of the BIOS in a computer?

The primary function of the BIOS (Basic Input/Output System) in a computer is to perform a system check at startup, known as the Power-On Self-Test (POST). During this process, the BIOS initializes and tests the system hardware components, such as the processor, memory, and storage devices. This ensures that everything is functioning properly before the operating system is loaded.

The BIOS also provides a basic interface for the computer to communicate with its hardware components, but its main role at startup is significantly focused on checking the system’s readiness. If any issues arise during this test, the BIOS will typically generate error messages or codes that can help diagnose the problem. This critical function sets the stage for the operating system to boot correctly, establishing the foundational operation of the computer's system.