BIOS is an acronym that stands for Basic Input Output System.Also know as "System Setup", the BIOS is software that is contained on a small memory chip on the PC's Motherboard, typically referred to as the CMOS (Complementary Metal Oxide Semiconductor).If you are a bit skeptical or doubtful when it comes to updating your motherboard’s BIOS, you have all the rights to be so because messing around with BIOS updates could be a very tricky business that renders your computer unusable.
When updating bios using asus update
This is called the ESCD (Extended System Configuration Data) and this is usually stored in additional non-volatile memory also referred to as NVRAM (Non-Volatile Random Access Memory) Over the years as technology has changed people still refer to the BIOS as both CMOS and NVRAM, however they are subtly different.
The CMOS contains the BIOS and its settings, the NVRAM contains the ESCD, updating the BIOS will not clear the NVRAM.
It acts as an interface between the computer's hardware and its operating system, e.g.
Windows, allowing the software to control the PC's hardware.
You can enter the system BIOS or Setup on a Dell PC by pressing F2 at the Dell loading screen.