What is a BIOS?



You’ve been asked to upgrade the BIOS on a customer’s computer. What is a BIOS?

A) The system memory, or RAM, of the computer system

B) The video adapter’s hardware drivers

C) The firmware that the computer hardware uses to communicate with the operating system

D) The hard drive storage of the computer


Answer: C) The firmware that the computer hardware uses to communicate with the operating system

The BIOS (Basic Input Output System) is the fundamental software built into the motherboard that manages the hardware interactions with the rest of the world. It doesn’t matter what operating system is running on the computer; the system still needs to understand how to interact with the keyboard, mouse, video display, and any other hardware.

The incorrect answers:

A) The system memory, or RAM, of the computer system
The BIOS does store information in flash memory called the CMOS (complementary metal-oxide semiconductor), but the system memory is a completely different set of chips. While the system memory may be gigabytes in size, the CMOS usually stores a few hundred bytes of information.

B) The video adapter’s hardware drivers
Video drivers always seem to need an upgrade, but they’re part of the operating system and unrelated to the system BIOS.

D) The hard drive storage of the computer
The hard drive storage has its own set of interfaces and/or adapters, but the storage subsystem is separate from the system BIOS.

Want to know more? Watch “BIOS and CMOS Overview.”


What really happens when you start your computer? In this video, we’ll show you how the BIOS handles the most basic operations of your personal computer and how the CMOS stores all of your important configuration information. We’ll also show you how to use VMware Player or Microsoft Virtual PC to create a test lab on your computer where you can test BIOS changes without modifying your PC settings.