Can you explain what BIOS is and why its role is important when starting a computer?

BIOS (Basic Input/Output System) is the fundamental input/output system embedded in a computer's motherboard. When the computer is turned on, BIOS performs initial hardware initialization (a process called POST — Power-On Self Test), checks connected devices, and loads the operating system loader from the hard drive or other media.

The role of BIOS is important because without it, the computer cannot start: it provides communication between hardware and the operating system, allowing the system to boot and operate correctly.