How does ROM help a computer start its operating system?

Read-only memory (ROM) facilitates the startup of a computer by storing essential firmware, such as the BIOS (Basic Input/Output System) or its modern successor, UEFI.

When a computer is powered on, the CPU accesses this firmware to execute critical start-up procedures. These procedures include:1

• Hardware Initialization: The system identifies and prepares available peripheral devices, such as keyboards, mice, and disk drives.1
• Loading the OS: The firmware locates and loads the operating system into the computer's main RAM, allowing the system to become functional.1

Unlike RAM, which is volatile and used for active processing, ROM stores data that typically cannot be modified during regular operation, ensuring that these vital instructions remain available every time the computer is turned on.2