List the four major components of bios ?

The four major components of BIOS (Basic Input/Output System) are:

1. BIOS firmware: It is a set of instructions or software code that is stored on a ROM (Read-Only Memory) chip on the computer's motherboard. It provides the basic instructions for the computer to start up and initialize hardware components during the boot process.

2. CMOS (Complementary Metal-Oxide-Semiconductor) memory: It is a small amount of volatile memory that stores the BIOS settings and configuration data. It allows the user to modify and save settings such as date and time, boot order, and hardware parameters.

3. BIOS drivers: These are software programs that allow the operating system to communicate with and control various hardware devices connected to the computer. BIOS drivers provide low-level access to hardware components such as the keyboard, mouse, hard drive, and display.

4. Power-on self-test (POST): It is a series of diagnostic tests performed by the BIOS during the boot process to ensure that the computer's hardware is functioning properly. POST checks the integrity of the CPU, memory, storage devices, and other essential components. If any errors are detected, the BIOS may display error codes or error messages to indicate the problem.